Single Point Mooring
The OCIMF mission is to
be recognised internationally as the foremost authority
on the safe and
environmentally responsible operation of oil tankers and terminals.
International Marine Forum
Table of Contents
LIST OF ABBREVIATIONS VII
1.0 INTRODUCTION 1
2.0 CLASSIFICATION SOCIETY
RULES AND OTHER PUBLICATIONS 3
2.1 Rules 3
2.2 Publications 3
2.2.1 OCIMF 3
2.2.2 International Chamber of Shipping (ICS) 5
2.2.3 ICS/OCIMF/IAPH 5
2.2.4 International Maritime Organization (IMO) 5
3.0 SINGLE POINT MOORINGS 7
3.1 Types of SPMs 7
3.2 CALM 7
3.3 SALM 8
4.0 OPERATIONAL PROCEDURES 13
for Berthing 13
4.1.1 SPM Pre‑Berthing Inspection 13
4.1.2 Ship Board Measures 14
4.3.1 Hose Connection 17
4.3.2 Hose Disconnection 18
4.6 Unmooring 19
4.6.1 Assisted Unmooring 19
4.6.2 Unassisted Unmooring 20
4.7 Safety 20
4.8 Pollution 21
5.0 INSPECTION SCHEDULES
AND PROCEDURES 29
5.1.1 Pre‑Berthing 29
5.1.2 Weekly 30
5.1.3 Monthly 31
5.1.4 Half Yearly 32
5.1.5 Yearly 32
Procedures for CALM Systems 33
5.2.1 Surface Fluid Swivel 33
5.2.2 Surface Piping and Expansion Joints 33
5.2.3 Main Turntable Bearing 33
5.2.4 Anchor Chains and Anchors or Anchor Piles 34
Procedures for SALM Systems 35
5.3.1 Submarine Main
5.3.2 Anchor Leg 35
6.0 MAINTENAN CE AND
MAJOR OVERHAUL 37
6.1 Planning 37
6.1.1 Factors Influencing Planning 37
6.1.2 Safety Precautions 38
Applicable to all Systems 38
6.2.1 Replacement of SPM Hoses 38
6.2.2 Replacement of Mooring Hawser and
Pick‑Up Rope Assemblies 38
6.2.3 Replacement of
Chafing Chains 39
6.3. Information Particular to CALM Systems 40
6.3.1 Replacement of
Main Turntable Bearing 40
6.3.2 Surface Fluid
6.3.3 Turntable and
Ancillary Equipment 41
6.3.4 Anchor Chains 41
6.3.5 Buoy 42
6.3.6 Buoy Towage 42
6.3.7 PLEM 42
Particular to SALM Systems 43
6.4.1 Buoy Body and
Anchor Leg 43
6.4.2 Submarine Main
Swivel and Hose Arm Assembly 43
6.4.3 Base 44
6.4.4 PLEM 44
7.0 DIVING AND ROV
7.1.1 Minimise the Need
for Underwater Intervention 55
7.1.2 Minimise Exposure
to Hyperbaric Pressure 55
7.1.3 Contract all
Underwater Work as a Service 55
7.1.4 Selection of
7.1.5 Inspection and
7.1.6 Controls 56
State, Swell and Currents 56
7.2.2 Surface Visibility 56
Safety Ckinsiderations 56
7.3.1 Over‑side Loads and Working 56
7.3.2 Surface Vessel Movements 56
7.3.3 Diving on Internally Pressurised Pipelines 57
7.3.4 Fishing from SPMs 57
Diving Safety Considerations 57
7.4.1 Pressure Related
7.4.2 Provisions for
Treatment of Pressure Related Illnesses 57
7.4.3 Diver Entering
and Leaving the Water 57
7.4.4 Head Protection 57
7.4.5 Use of Closed‑Circuit
Television (CCTV) 57
7.4.6 High Pressure
Water Jetting Equipment 57
7.5 Use of
Hyperbaric Diving Services 58
7.5.1 Surface Oriented
7.5.2 Self Contained
Underwater Breathing Apparatus (SCUBA) 58
7.5.3 Surface Supplied
Breathing Apparatus (SSBA) 58
7.5.5 Use of
Nitrogen/Oxygen (Nitrox) Breathing Gas 59
7.5.6 Diving Team Size 59
7.5.7 Diver Competency 59
7.6 Use of
Remotely Operated Vehicles (ROV) 59
7.6.1 ROV Capabilities 59
7.6.2 Types of ROV
126.96.36.199 Low Cost ROV (LCROV) 60
188.8.131.52 Observation Vehicles 60
184.108.40.206 Work Class Vehicles 60
8.0 SUPPORT FACILITIES 63
8.1 Craft for
Marine Operations 63
8.1.1 Mooring Launches 63
8.1.2 Maintenance Vessels 64
8.1.3 Use of Tugs in Operational Support 65
Maintenance Facilities 65
8.2.1 Yard and Storage Facilities 65
8.2.2 Facilities for Major Overhaul 66
8.2.3 Dock Space for Service Vessels_ 66
9.0 SPARE PARTS 67
9.1 Spare Parts ApplJ1cable to all Systems 67
9.2 Spare‑P 'rt Applicable to
CALM Systems only 68
9.3 Spare Parts Applicable to SALM Systems
10.0 RECORDS 69
10.2 Typical Areas
to be C(3vered‑ by the Record System 69
10.2.1 Pre and Post Mooring Checks 69
10.2.2 Operating Mooring Data 70
10.2.3 Equipment Performance 70
10.2.4 Overall SPM Performance 71
List of Abbreviations
API American Petroleum
CALM Catenary Anchor Leg
CCTV Closed Circuit Television
CONCAWE The Oil Companies'
European Organization for Environment, Health and Safety.
DDC Deck Decompression Chamber
HP Horse Power
1APH International Association
of Ports and Harbors
ICS International Chamber of
IM0 International Maritime
MSL Mean Sea
OCIMF Oil Companies
International Marine Forum
PLEM Pipe Line End Manifold
psi Pounds per square inch
Psig Pounds per square inch
SALM Single Anchor Leg Mooring
Underwater Breathing Apparatus
SPM Single Point Mooring
SSBA Surface Supplied Breathing
SWL Safe Working Load
VHF Very High Frequency
efficient, safe and reliable operation of Single Point Mooring (SPM) terminals
is largely achieved by the use of established operating procedures and by
regular inspection and maintenance. Manuals providing detailed instructions to
operation and maintenance personnel enable sound procedures to be established.
objective of this publication is to provide guidelines to operators of SPM
terminals to assist in the preparation of manuals for their particular terminal
facility. This publication provides a framework and a basic outline of
procedures based on extensive experience gained by several companies with
various types of SPM facility. These basic guidelines should be supplemented
and modified to suit the particular requirements of the SPM facility. A list of
applicable rules and publications for reference purposes is provided in Section
of these guidelines is restricted to the two most common types of SPM. These
are the CALM (Catenary Anchor Leg Mooring) and the SALM (Single Anchor Leg
Mooring). A brief description of both types of facility is given in Section 3.
0. SPM facilities specially designed to accept dedicated tankers are beyond the
scope of this publication. Many of the guidelines, however, can be selectively
applied to these and other types of SPM.
should be supplemented by a description of the terminal organisation and by a
detailed description of the particular terminal facility including charts,
diagrams and local environmental conditions.
operational procedures, inspection schedules and procedures, and guidelines for
maintenance procedures are provided in Sections 4.0, 5.0 and 6.0 respectively.
inherent to the operation and maintenance of SPM facilities. Section 7.0
provides guidelines for air‑diving in the vicinity of SPM facilities to a
maximum depth of 50 metres. Techniques for diving deeper than 50 metres are
beyond the scope of this publication.
overview of the types of support craft and shore facilities required is
provided in Section 8.0.
and efficient operation of an SPM facility requires spare parts to be readily
available in the event that replacement of components is required. Section 9.0
provides general guidelines for the quantity of spare parts to be held in
stock. These guidelines are based on experience.
comprehensive record system provides the most reliable basis for the
establishment of rational inspection and maintenance schedules for a particular
SPM facility. Guidelines for the type of records required are provided in
Section 10. 0.
Section 2. 0
It is possible to classify SPMs in accordance with the rules and
regulations of classification societies. Of the several societies that classify
SPMs, the following have published rules:
American Bureau of Shipping
Rules for Building and Classing Single Point Moorjngs.
Det Norske Veritas
Rules for the Design Construction and‑ Inspection of
Offshore Loading Systems.
Guidance Notes for Single
Point Moorings, Buoys and Similar Tethered Floating
The latest editions of the following publications are
applicable to the operation and maintenance of SPM facilities.
Guide to Purchasing, Manufacturing and Testing of Loading and
Discharge Hoses for Offshore Moorings.
This publication gives
the minimum specification of acceptable technical requirements to ensure the
satisfactory performance of rubber, reinforced, smooth bore, oil suction and
discharge hoses for offshore moorings. The specification is divided into two
parts: technical requirements for commercial hoses and technical requirements
for prototype hose approval. Notes to the purchaser are included listing items
which should be specified or agreed with the manufacturer. It includes
reference to double‑carcass hoses, lifting lug requirements, float design
requirements, standardisation of bead float collars and standards for packing.
Guidelines for the Handling, Storage, Inspection and Testing
of Hoses In The Field.
Gives guidance on the handling, storage, inspection and
testing of hoses under service conditions.
SPM Hose Ancillary Equipment Guide.
Gives guidance on common
descriptive terminology and technical requirements for the designer and
operator of SPM systems.
SPM Hose System Design Commentary.
A commentary on the two
most common types of SPM (CALM & SALM) reflecting modern practices,
providing descriptive terminology together with an outline of present practice
in the design of hose systems.
Recommendations for Oil Tanker Manifolds and Associated
aimed at introducing conformity in manifold arrangements for all ocean going
tankers engaged in the transport of crude oil and bulk liquid petroleum
products, including guidance on vapour recovery manifolds.
Recommendations for Equipment Employed in the Mooring of Ships
at Single Point Moorings.
aimed at facilitating correct matching between the SPM and the ship. Recommends
that mooring equipment available at terminals be brought into line with these
standards and that ships be provided with bow stoppers and associated fittings
designed to secure and accept standard chafe chains.
Hawser Test Report.
Gives a complete
description of the first major large rope testing programme. This was
undertaken to determine the actual new and used strengths and rate of strength
reduction of large synthetic ropes similar to those used as SPM hawsers. All
the test data and analyses are included together with conclusi6ins and
recommendations. It will be of interest to designers and operators of SPMs and
to all who manufacture or use large, synthetic ropes for lifting and mooring.
These three booklets are
produced with the intention that rope manufacturers establish complete and
detailed documentation of their synthetic fibre products, particularly those
primarily intended for use at single point moorings.
Volume 1 ‑ Guide to Purchasing Hawsers.
Volume 2 ‑
Procedures for Quality Control and Inspection During the Production of Hawsers.
Volume 3 ‑ Prototype Rope Testing.
Marine Terminal Survey Guidelines.
This guide and the
checklists appended have been published to provide a tool that may be used by
terminal operators/owners to encourage the assessment of standards of safety
and oil spill control at oil terminals on a world‑wide basis.
Oil Spill Contingency Planning ‑ A Brief Guide.
This guide aims to
provide a general overview of the whole subject of clean‑up, in brief and
simple terms, for the guidance of those in the oil industry concerned in
contingency planning, government relations and public affairs.
Response to Marine Oil Spills (ITOPF).
This book is designed to
be of maximum practical benefit to those involved in training programmes,
contingency planning or actually responding to oil spills.
International Chamber of Shipping (ICS).
Ship/Shore Safety Check List Guidelines.
The check list covers the
handling of dangerous liquid substances in bulk, including liquefied gases, and
aims to ensure that there is a proper exchange of information between those
responsible for the operations on board ship and those ashore.
Guide to Helicopter/Ship
This guide has been prepared primarily for the use of masters, officers and
crew, but it also provides guidance for helicopter pilots with a view to
introducing standardised operational procedures for helicopter/ship operations
on a world wide basis.
2.3.3 OCIMF / ICS / IAPH
Guide for Oil Tankers and Terminals (ISGOTT).
This safety guide makes recommendations for practices to be adopted by
tanker and terminal personnel to ensure safety in operations relating to the
carriage by sea and the handling on tankers and at terminals of crude oil and
2.2.4 International Maritime
Recommendations of Safe
Transport, Handling and Storage of Dangerous Substances in Port Areas.
The recommendations provide a standard framework for use in the preparation
of regulations to ensure the safe transport, handling and storage of dangerous
substances in port areas. The recommendations are operational in nature and do
not. deal with such aspects as ship's construction and equipment.
Single Point Moorings
terms, an SPM consists of an integrated mooring and fluid transfer system to
which a tanker is moored by its bow. Fluid is transferred between the tanker
and the SPM through flexible hose strings. A mooring swivel, concentric with a
fluid swivel, allows the tanker to swing freely around the SPM in response to
changes in the environment. This weather‑vaning capability allows the
vessel to remain moored in more severe environments than would be possible at
other types of facility, such as piers, sea islands or multi‑buoy moorings.
manoeuvring area must be available for a tanker to approach the mooring point,
remain moored during loading and discharging and vacate the berth in a safe
manner. The selected area must therefore have sufficient water depth in the
approach route and manoeuvring area to accept the largest class of tankers
expected to use the terminal and to ensure that the ship's underkeel clearance
is sufficient so clear the seabed and other obstacles such as pipelines, the
Pipe Line End Manifold (PLEM) and the submarine hose strings. The required
water depth must also allow for the maximum heave, pitch and roll to be
experienced by the visiting tankers.
In certain circumstances tugs may be used to assist tankers
when manoeuvring, the use of tugs is optional and determined by the terminal location and
3.1 TYPES OF SPMs
These guidelines are restricted to the two most common types of SPM. These
are the CALM (Catenary Anchor Leg Mooring) and the SALM (Single Anchor Leg
Mooring) which are the principal types of
SPM used as tanker terminals. Many of the guidelines in this manual,
however, can selectively be applied to other types of SPMs, such as the
specialised SPM facilities installed for the use of dedicated tankers.
A tvpical CALM system, as shown in Figure 3.1, consists of the mooring
buoy, chain and anchor system, mooring
assemblies and floating and submarine hose strings.
The mooring buoy is normally steel and has typical dimensions of 12 m
diameter and 5 m height. The buoy body provides the necessary buoyancy to keep
the system afloat and this is accomplished by watertight compartments
located in the outer buoy body. A rotating deck or turntable is mounted on of
the buoy body and is designed to transmit mooring forces from the mooring
assemblies through buoy to the anchor chains. The turntable carries the fluid
piping which connects to the fluid swivel by located in the centre of the buoy.
The swivel assembly consists of separate concentric chambers, the number
of which depends on the number of fluids to be pumped through the buoy. The
piping is also connected to the floating hose strings outboard of the
The CALM anchoring system
consists of 4 to 8 anchor chains, extending from the buoy body radially out and
terminating at firmly
embedded anchors or anchor piles. Since the anchor chain system is a spring‑type
system which has to withstand mooring forces, and thereby station the SPM, each
anchor system must
be designed for the specific location.
Vessels are moored to the CALM by one or more hawsers attached
to the turntable. Hawsers are normally made of synthetic fibre with dimensions
depending on tanker size and local operating conditions.
The floating hose strings connect the overboard pipework of
the turntable with the manifold of the moored tanker. Floatation is externally
attached or built into these hoses. The hose string length is determined by
mooring equipment, tanker size and manifold location.
The submarine or under‑buoy hose strings form the
connection between the fluid swivel assembly on the buoy and the submarine PLEM
(Pipeline End Manifold). Due to the lateral and vertical displacement of the
buoy in response to sea conditions and mooring forces, the length and
configuration of the under‑buoy hose strings has to be such that, at the
maximum possible distance between buoy and PLEM the hose strings are not over
stressed and, at the minimum distance between buoy and PLEM. the hose strings
are not damaged due to kinking or bottom contact. Optimum hose string configurations
are, therefore, of the utmost importance and can only be accomplished by proper
engineering. The number of hose strings can vary, depending on the throughput
and the number of fluids handled.
Submarine hoses can be installed in various configurations,
which can include lazy S, steep S, or Chinese lantern arrangements. Refer
figures 3.3, 3.4, 3.5
A typical SALM system, as shown in Figure 3.2, consists of a
mooring buoy attached to a gravity or pile base by a single anchor leg.
The mooring buoy is normally steel and has typical dimensions
of 4 m diameter and 12 m height. Vessels are moored to the SALM by one or more
hawsers connected to the mooring buoy. Hawsers are normally made from synthetic
fibres with dimension depending on tanker size and local operating conditions.
The SALM anchoring system has two main sections, the base and
the anchor leg or riser. The base is the principal structural member which
secures the SALM in position. It is designed to carry the horizontal and
vertical forces which result from the mooring loads. The single anchor leg is
usually a large chain with a swivel incorporated to allow buoy rotation and
prevent chain torquing. Universal joints are at both ends of the chain to
A fluid swivel is
mounted concentrically about the anchor leg either on top of the base or on top
of a riser. The fluid swivel permits the passage of fluid while rotating in
response to the moored vessel's movements.
The hose strings for the SALM extend from the fluid swivel
unit to the moored tanker manifold and are comprised of submarine and floating
hoses which should be designed to withstand the bending forces required to
rotate the swivel unit. This is typically arranged such that under normal
conditions, the hose strings will extend in a gentle configuration from the
fluid swivel unit to the surface. Under extreme conditions the hose strings
should maintain a satisfactory configuration. The mooring base may be connected
to the submarine pipeline either by rigid piping or by jumper hoses from the
SALM base to a PLEM.
procedures are only a general outline and should be amended to suit
particular requirement. , All terminals have
different operating parameters due to location and design criteria and the
following procedures are intended to provide a basis for operating companies
to prepare their own specific operating
part of the operation of an SPM entails working from a launch or handling heavy
equipment . Whilst the work is
usually carried out under the supervision of a berthing master, it is not
without danger and precautions should be taken to ensure the safety of the
4.1 PREPARATIONS FOR
Prior to arrival of
a tanker, it is essential that a proper line of communication is established
between ship and the terminal.
The terminal should provide
the arriving tanker with a message advising mooring arrangements, hose
connection details and port requirements, including details of any prohibited
anchor areas. The message should request
details of the tanker's arrival draft, and expected sailing draft, mooring
arrangements, manifold sizes, bow to manifold distance, SWL (Safe Working Load)
of lifting equipment and ability to comply with international safety and
pollution prevention standards in force.
The exchange of information should be made as early as possible, preferably
at least 72 hours before
After the exchange of information, the terminal should ensure that the
tanker can safely occupy the
4.1.1. SPM Pre‑Berthing
Prior the berthing of the tanker, an
inspection should be made of the SPM, workboats and all an equipment to be used
the tanker and connecting the hoses. The
following describe the inspection checks
required prior to berthing.
A schedule of pre‑berthing inspection
is also provided in section 5.1.1.
The berthing master and his mooring crew should check that the
freeboard and trim of the buoy we correct and if possible board the buoy to
check that the hatches are secure. The mooring hawser connections should then
be inspected for tightness and damage and the correct operation of navigation
For CALM type SPMs the condition of hose connections, valves,
pipework and the fluid swivel should be inspected for tightness and leaks and
the valves checked for correct setting. The turntable should be checked for
free rotation and for any unusual noises from the main bearing or fluid swivel.
If installed, the telemetry and instrumentation required for
monitoring mooring load, fluid pressure and temperature and for the operation
of valve actuators should be switched on.
In certain circumstances it may be preferable to include
inspection of the submarine hoses and PLEM valves during pre‑berthing
inspection. This will depend upon the frequency of the use and operational
circumstances of the SPM.
The floating hoses should
be inspected by launch to ensure that they are not damaged and are streaming
freely. Careful attention should be paid to the hose pick‑up arrangements
to ensure that they are not fouled.
If applicable, hose marker lights should be checked to ensure
that they are operational.
For SALM type SPMs the
distance between the point of submergence of the hose strings and the buoy
should be checked against the optimum design distance to verify that the
submarine hose configuration is correct and that submarine hose 'wrap‑around'
has not occurred.
The hawsers should be
carefully inspected by launch to check for damage. The chain support buoys and
pick‑up ropes should be checked to ensure that they are streaming freely.
A simple way to do this is to pull the pick‑up rope with the mooring
launch so that the pick‑up rope and mooring assembly is stretched.
Careful attention should be paid to the connection between the pick‑up rope
and the chafing chain.
If two separate hawsers
are to be used in the mooring during mooring
activities, the one furthest away from the floating hoses should be tied
back on the SPM so that it is clear until required.
The following ancillary mooring equipment should be inspected
for condition prior to mooring:
The following ancillary hose connection equipment should be
similarly inspected for condition:
‑ Tools for connecting hoses to reducers and
‑ Assorted strops and shackles
‑ Hose snubbing ropes
- Chain blocks
- Pressure gauges
‑ Oil spill clean up material
‑ Hose pick‑up arrangement
4.1.2 Shipboard Measures
Prior to approaching the buoy, the following shipboard measures should be
accommodation ladder should be made ready, in accordance with SOLAS, for access
on the side advised by the berthing master. The location should be away from
that required for hose handling.
If pilot embarkation is by helicopter, safety precautions
should be taken on board the tanker in accordance with ICS recommendations.
Power should be on the winches on the forecastle and to the
derricks or cranes at the ships manifold which should be made ready to lift the
ancillary mooring and hose handling equipment. Hoses will generally be connected on the port side of the tanker, amidships,
and the manifolds should be made ready. Local conditions sometimes require that
hoses should be connected on the starboard side, but this is unusual.
Notification will, in any case, be given from the terminal.
A messenger line should be placed on the forecastle head, this
should be either a 24 mm dia. nylon rope, 90 in long, or alternatively a rope
of equivalent strength. A large hammer and fire axe should also be available
A typical mooring operation is as follows:
When contact is made with the approaching tanker, normally by
VHF (Very High Frequency) radio, the berthing master should confirm the mooring
arrangements and hose connection details, and the ship master should confirm
that trial engine manoeuvres have been successfully completed. The mooring plan
should be made after the first exchange of information as described in Section 4.1. Recommended mooring procedures are shown in Figure
The berthing master and his assistant should board the tanker
prior to the tanker's approach to the SPM and should bring on board the
required ancillary equipment for mooring and hose connection. One of the
mooring launches will be used for boarding and it is preferable that the
ancillary equipment is made ready for a single lift by the tanker's derrick.
The mooring launch should return to the SPM to await the tanker's approach.
Meanwhile, the tanker master, using the advice of the berthing
master, should carefully study the wind, waves and current to determine the
best approach direction. The approach should be made from the direction in
which the tanker can best be handled at very slow speed and can be best held
stopped in the water. The berthing master's assistant should be stationed on
the bow during the approach to the buoy, and for the full duration of the
mooring operation he should remain on the forecastle in radio contact with the bridge, until he is satisfied that the vessels securely moored.
In order to avoid damage to submarine pipelines and SPM anchor
chains, ships anchors should not be dropped within the manoeuvring area except
in extreme emergency. The berthing master, or his assistant, should check and
ensure that the anchors are fully home and secured before making the final
During the approach the mooring equipment should be prepared
on the tanker's bow according to the way in which the tanker is to be moored.
At this time, a mooring launch should tow the floating hose
strings away from the tanker's direction of approach in the form of a bight to
ensure that the hose strings are kept clear of the vessel's propellers during
berthing. A second launch should assist with the actual mooring operation. In
some locations, it may be possible to use one launch to perform both functions.
The final approach should never be made until the launches,
the mooring equipment, and forecastle area arrangements are confirmed as being
ready and suitable by the berthing master's assistant.
In making the final approach, the tanker should take a course
which will avoid contact with the SPM, moorings and hose strings. If the tanker
overshoots and the mooring has to be suspended, the tanker can then pass clear
in safety and will be able to manoeuvre for a second approach.
At a convenient safe distance from the SPM, the berthing
master should advise the ship's crew to lower a messenger line through the
fairlead which is to be used for the mooring. The fairlead should be as close
to the centre line of the tanker as possible. The messenger line should fall
aft from the bow so that the launch can come alongside without having to
manoeuvre under the bow or be affected by a bulbous bow. If a bow thruster is
fitted, it should be stopped during this stage of the operation.
The launch should take the
messenger line and connect it to the mooring pick‑up rope. If two
separate mooring assemblies are to be used, the first one to be connected will
be the one nearest to the floating hose strings. The pick‑up rope is
commonly 80 min dia. and 150 in in length. If pick up buoys are fitted to the
pick‑up rope, they should be disconnected when the messenger is attached
and stowed on the launch.
When the messenger line has been connected, the tanker should
manoeuvre to within 50 in of the SPM. As soon as the launch is clear, the
messenger line should be winched on board the tanker as quickly as possible.
The pick‑up rope should be transferred to the winch and heaved in until
the chafing chain passes through the fairlead and reaches the required
position, it is essential that the lead of the pick‑up rope between the
fairlead, through the bow stopper, and to the winch, should be as direct as
possible. Care should be taken when winching in the pick‑up rope to
ensure that there is always some slack in the mooring assembly. The use of the
pick‑up rope to heave the vessel or maintain the vessel's position is
dangerous for the personnel involved in the operation and should never be
attempted. Care should be taken if drum ends are used to heave the pick‑up
rope and mooring assembly on board.
Consideration should be given, if it is practical, to using a
self‑spooling drum for the pick up arrangement. This will necessitate emptying
the drum of other rope prior to arrival.
Once the chafing chain is in the correct position, it should
then be secured to the tanker in the stopper as expediently as possible and
before the moorings come under tension. If two mooring assemblies are to be
used the second chafing chain should be heaved on board using the same
procedure and secured as close to the other as possible. Both mooring
assemblies should be the same length when secured.
Whilst the mooring assemblies are being connected, the tanker should remain stopped relative to the
buoy with the mooring assemblies slack. It can be very dangerous to the mooring
crew if the mooring assembly is allowed to become tight before the connection
is completed. When the connection is made, the tanker should be allowed to
settle back slowly on the mooring assemblies.
The mooring operation can
be carried out by day or night. During night berthing, the launches should
assist the berthing master by indicating the location and direction of the
floating hose strings and mooring assemblies by illuminating them with their
search lights. During the final approach, the berthing master should use the
searchlights to gauge his distance from the hoses and the SPM. Good
communications between the berthing‑master, his assistant on the bow, and
the launches is of particular importance during night berthing.
Whilst the tanker is secured to the SPM, the berthing master
should ensure that suitable precautions are taken to monitor the vessel's
position relative to the buoy to prevent the vessel from riding up to the buoy
or yawing ‑excessively. It may be necessary to station an experienced
crew member equipped with radio communications in the fore part of the vessel.
The tanker's engines should remain on stand by and ready for immediate use at
all times. If tugs are used in the berthing operation or in accordance with
8.1.3, proper preparation should
have been made for securing the tugs and sufficient manpower should be
4.3 HOSE HANDLING
Hose handling should always be carried out with the hose string de‑pressurised, or under
slight internal pressure. The berthing master's assistant will advise the
tanker crew on hose handling procedures.
4.3.1. Hose Connection
After the vessel is securely moored, the berthing master
should instruct launch to tow the ends of the floating hose string to a
position underneath the tanker crane or derrick. If more than one hose string
is to be connected, one hose string should be handled at a time. It is
essential that the hose string nearest the tanker is connected first and in
manifold order from forward to aft. The hose connection should be made in
accordance with the following procedure.
Preferably the vessel's hose lifting crane or derrick should
be positioned such that the hose can be lifted vertically outboard of the side of the vessel.
The tanker crew should lower the crane or derrick hook and the
launch crew should insert the hook into the hose lifting chain. The hose should
then be lifted out of the water to enable the pick‑up buoy to be
disconnected at the tanker rail as shown in Figure 4.2 –
At this time, the condition and security of the various hose
lifting gear components should be visually inspected for excessive wear,
damage, or poor connections.
The hose should then be lifted to a sufficient height to
enable the hose supporting chain to be attached and to facilitate hose
connection. When the hose is at the correct height, a wire should be connected
to the slip hook and fastened with a minimum of slack to suitably located bitts
as shown in Figure 4.2 ‑Sequence 2. The method indicated is commonly used
but other arrangements, including the use of chain secured directly to the
bitts, have been developed. Terminals should determine the optimum method for
The hose should then be lowered to transfer the full weight to
the hose supporting chain. The derrick can be adjusted inboard. A snubbing rope
positioned around the hose and secured to the tanker rail will assist lining up
the hose to the tanker manifold and preventing lateral movement during
connection. The height of the hose should be sufficient to allow the hose tJ be
bent over to the tanker manifold and for the hose and manifold flanges to be
aligned. It is prudent to allow a little extra height as it is easy to slacken
the wire a little to achieve accurate alignment.
The hose should then be bent down so that the blind ‑flange
on the hose can be removed. Before removal a check should be made to ensure
that the line is de‑pressurised and a spill tank or drip tray should be
positioned to contain any leakage. The hose should then be connected up as
shown in Figure 4.2 ‑ Sequence 3. The hose should be connected to the
manifold using bolts or acceptable quick coupling devices.
All bolted connections should use the full number of bolts and
tightening should be in a diagonal sequence. High quality gaskets should be
If the end of the floating hose string is sealed by a
butterfly valve, the valve should be locked in the open position during cargo
transfer operations. Valves should never be operated when oil is flowing
through the hoses in order to avoid surge pressures.
When the hose connection has been made, a strop should be
connected to each hose string and hooked onto the derrick as shown in Figure
4.2 ‑Sequence 3. The strops should be used to achieve the best radius
configuration. The snubbing ropes should be left in position to minimise
lateral movement of the hoses induced by swell.
During the hose lifting and connection operation, care should
be taken to ensure that the weight of the hose string is not taken off the
support chain by other than the prescribed lifting gear. In particular, the
strop should not be used to take the full weight of the hose string to adjust
the support chain.
4.3.2. Hose Disconnection
The disconnection of
hoses can be dangerous and care should be taken to ensure that the hoses 2‑~ secured to the tanker or derrick at all times, until
they are lowered to the sea. Before disconnection , , the hoses, they must
be flushed or emptied and depressurised. The manifold valves and hose valves,
if fitted, should be closed to the satisfaction of the berthing master or his
It is essential, if more than one hose string is used, that
the hoses are disconnected in sequential order from aft to forward. This will
avoid the hoses fouling each other when they are lowered to the sea.
To disconnect each hose, its weight should be taken on the
derrick at the strop and the manifold bolts disconnected. Care should be taken
to stop the hose moving when the bolts are removed and this is most easily done
by securing a tine around the hose near the flange and fastening it to
convenient bitts. When disconnected, the hose should be blanked off using a
blind flange and a good quality gasket. All bolts and nuts must be properly
tightened to prevent oil leakage when the hose string is later pressurised.
When the blind
flange is secure, the derrick hook should be transferred from the strop to the
hose pick up arrangement. The hose should be slowly lifted to the vertical,
while slacking away on a steadying rope attached near the blind flange. When
the hose hangs vertically and the derrick has the full weight, the snubbing
rope and supporting chain may be disconnected. The hose should be lowered until
the pick up arrangement is level with the tanker rail. The marker buoy may be
reconnected to the pick up arrangement at this time.
A line should be passed through the pick up arrangement and
secured to the tanker so that it can be used as a slip rope. Care should be
taken to ensure that the slip rope is long enough to lower the hose to sea
level. The hose string should then be hung off the slip rope with the blind
flange at deck level and the derrick hook disconnected. If more than one hose
string is used the other hose strings should be disconnected using the same
The hoses should remain in this position until the tanker is
ready to depart. Whilst the tanker is securely moored the hoses should 6e
slowly lowered (aft hoses first) to the launch, so that they can be towed
clear. Alternatively, the hoses may remain hung off in this manner until the
moorings are cast off. The hoses can then be lowered without the need of a
launch and will not foul the ship's propeller. It is an unsafe practice to keep
the hoses connected in whatever form after the mooring ropes have been
4.4 CARGO OPERATIONS
The basic procedures for cargo handling at SPMs are the same as those for a
Since good communications are of the utmost importance for
safe cargo handling, a reliable communications system, including a secondary
stand‑by system, should be established and tested.
Prior to a tanker arriving to load or discharge a proper
exchange of information should be made between the terminal and the tanker.
This should include a check on the ability of the tanker to comply with the
international tanker safety and pollution prevention standards.
Upon arrival of the tanker, it should be inspected as to it's
compliance with industrial standards, both from a technical as well as from an
operational point of view.
The loading or discharging plan, as well as the arrangements
for emergency shut down of cargo operations, should be agreed between the
berthing master and the responsible tanker officer during a pre‑transfer
conference and recorded in writing.
The ISGOTT Ship/Shore Safety Check List should be completed,
and checked and signed at regular intervals throughout operations.
A joint ship‑shore pumping and valve closing regime
should be established and maintained to avoid pressure surges.
Where automatic/remotely controlled valves are used to stop or
divert flows, their closing characteristics, together with the planned
discharge/loading rate, shall be laid down and checked against established
maximum permissible surge pressures in the shore and ship pipeline system.
Cargo transfer operations should not commence until the ship's
officer on duty and the berthing master are satisfied and have agreed that the
hoses are correctly connected and that all necessary ship, buoy and terminal
valves have been set for receiving or discharging cargo, and that the
communication link between ship and shore is established and functioning.
Cargo transfer should begin slowly until it has been verified
that oil is reaching the designated tanks and that the whole system is
operating satisfactorily. The hose strings and the area around the mooring buoy
should be inspected from the mooring launch for evidence of leakage. When it
has been firmly established that the total system is operating correctly, the
pumping rate may be increased to the maximum rate as specified by the shore
station or the ship as the case may be. A member of the tanker crew, equipped
with radio communications, should be continuously on watch on deck. Sufficient
crew should remain on board to deal with the operation and security of the
tanker. During cargo operations periodic inspections should be made of the
manifold connection, the entire hose system, and the areas around the ship and
mooring buoy. At regular intervals the pressure at the manifold and the
quantity of cargo transferred should be recorded by both ship and shore and the
figures compared with each other. Any marked discrepancy between quantities
should be investigated immediately.
Upon completion of cargo transfer, it is essential that the
ship's valves remain open until oil flow has ceased completely. The berthing
master must wait for confirmation from shore before directing that the ship's
valves should be closed.
4.5 BALLAST OPERATIONS
Ballast control at SPMs is important. If tankers are properly
fitted with segregated ballast systems or suitable clean ballast systems they
should always commence ballast operations concurrently with cargo transfer
operations in order to avoid being secured to the SPM in a light‑ship
condition. Tankers secured to SPMs in a light‑ship condition can be
difficult to control. This condition should be avoided.
For tankers which are unable to handle ballast concurrently
with cargo, it may be beneficial to increase the ship's draft in poor weather
conditions by suspending cargo discharge to take on ballast or by suspending
ballast discharge to take on cargo as appropriate. At all times international
tanker safety and pollution prevention
standards should be complied with.
4.6.1. Assisted Unmooring
Before unmooring, the connection between the pick up rope and
the chafe chain should be checked and replaced as necessary. All unnecessary
ancillary equipment should then be loaded onto the mooring launch and non‑essential
personnel should be disembarked. The mooring launch should come alongside in
the vicinity of the manifold and the hoses should be lowered, in turn from aft
to forward, and passed to the launch. The launch should then tow the hoses away
from the tanker and hold them in a bight away from the line of departure. As an
alternative, if conditions permit, the rail hoses can be tied back to the SPM
thus freeing the launch for other duties.
The weight should be taken off the mooring assemblies, if
necessary, by an ahead movement on the tanker's engine. The pick up rope should
then be heaved on the winch and the chafing chain let go from the bow. The pick
up rope should then be slowly paid out through the fairlead. If two mooring
assemblies are used they should be let go together if possible, but if they
have to be disconnected separately, the one nearest the floating hose should be
let go first. The pick up rope should be slow1N slackened until the chafing
chain is in the water. Care should be taken to avoid lowering the mooring
assemblies across each other or over the floating hoses. Whilst the pick up
ropes are being lowered, the tanker should come slowly astern until it is clear
of the SPM. When the tanker is clear, the launch should come alongside to
receive the ancillary equipment and to disembark the berthing master and his
When the tanker has departed, the berthing master should
supervise the disconnection of the mooring assemblies from the SPM, if this is
to be done, or alternatively, check that they are in good condition. A similar
inspection of the floating hose strings and the SPM, should be made.
All monitoring and telemetry equipment on the SPM should be
switched off, as necessary. The navigational equipment should be checked and
the SPM left in good order.
The berthing master, assistant and launches are then free to stand down.
4.6.2. Unassisted Unmooring
Before unmooring, the hoses should be disconnected and hung off at the tanker's rail. Two seamen
should be stationed at the hand off point under the supervision of the berthing
master's assistant in readiness for letting go. The hose slip ropes should be
slowly slackened and the hose string lowered to sea level as described in
The weight should be taken off the mooring assemblies using the tanker's
helm and engines.
On the forecastle, the pick‑up ropes should be heaved on
the winch and the chafe chain let go from the bow. The pick‑up rope
should then be lowered slowly. When the chafing chain reaches sea level and the
weight is off the pick‑up rope it should be cast‑off from the
tanker and the tanker should slow come astern to clear the berth. If two
mooring assemblies are used, they should be let go together if possible, but if
they have to be disconnected separately, the one nearest the floating hose
should be let go first. Care should be taken to avoid lowering the mooring
assemblies across each other, or over the floating hoses.
As the tanker gains sternway and at a time when the floating
hoses cannot foul the ship's propeller, the hose strings should be cast off.
When the tanker is clear, the launch should come alongside to
receive the ancillary equipment and to disembark
the berthing master and his assistant.
When a tanker is secured to an SPM, the recommendations which
are given in the International Safety Guide for Oil Tankers and Terminals
(ISGOTT) should be followed. This guide makes recommendations for practices to
be adopted by tanker and terminal personnel to ensure safety in operations
relating to the carriage by sea and the handling on tankers and at terminals of
crude oil and petroleum products.
Good communications should be maintained at all times between
the ship, shore terminal and mooring launches.
If the berthing master considers it necessary he may require
that an experienced crew member equipped with radio communication is stationed
in the fore part of the vessel.
A member of the tanker crew should be continuously on watch on
deck. Sufficient crew should remain on board to deal with the operation and
security of the tanker.
The agreed ship‑to‑shore communications system should be
maintained in good working order.
A responsible member of the terminal organisation should be on
continuous duty at the shore end of the ship‑to‑shore communication
At the commencement of loading or discharging, and at each
change of watch or shift, the responsible officer and the terminal
representative should confirm with each other that the communication system for
loading and discharging control is understood by them and by personnel on watch
and on duty.
The stand‑by requirements for normal stopping of shore
pumps on completion of loading and the emergency stop system of both tanker and
terminal should be fully understood by all concerned. I I
During cargo transfer, the hose strings and SPM should be
regularly inspected, and monitored for leakage.
The hose strings in the vicinity of the tanker manifold and
tanker rail should be regularly inspected by the berthing master or his
representative for distortion and chafe.
Regular inspections of the mooring assemblies and hose
connections should be carried out and defects such as loose shackles made good
immediately. It is important that such inspections are made immediately prior
to letting go of the hose strings and the mooring assemblies.
Pressure, temperatures and cargo quantity checks should be
made at regular agreed intervals and the, results compared between the tanker
and shore. Any variances should be investigated immediately.
A mooring launch should be available whilst the tanker is in the berth.
Instrumentation is sometimes used on SPMs. The use of
telemetry systems enables remote monitoring of many aspects of SPM operations
to be carried out. Probably the most important monitoring equipment is that
used to measure mooring loads. The mooring loads are normally transmitted by
telemetry to the shore terminal where they can be recorded. Additionally, the
signal can be transmitted directly to a portable receiver in the berthing
master's possession. Such instrumentation can be used to give early warning of
reaching maximum allowable mooring load conditions and to enable tankers to
safely use the SPM to maximum berth occupancy, particularly during changing
weather conditions. It is recommended that terminals have suitable
environmental parameters in place to ensure that operations can be carried out
in a safe manner. Suitable equipment should be available to enable these
parameters to be measured.
The risk of oil spillage and pollution will always be present
as long as oil is being shipped and stored. However, most accidents are not
caused by natural events, but by human error and technical failure. This means
that spills can be prevented by appropriate instruction and training of
personnel, which is far more
effective than fighting pollution after spillage has occurred.
SPM facilities do not present a greater pollution risk than a
conventional alongside berth. The possibility of spillage however clearly
remains and therefore at every location a contingency plan for fighting
pollution should be available. There is world‑wide agreement as to the
rights and duties of national governments to protect their coastal areas
against environment degradation. In case no national government supported
contingency planning exists, industry should take a lead to promote such a plan
for dealing with the first steps of pollution resulting from its activities.
Advance consultation and agreement between government and
industry on action programme is an essential requirement, as any effort to
fight oil pollution without the proper organisation and support will achieve very little, when a national
emergency condition occurs.
Section 5. 0
Inspection Schedules and
To ensure efficient,
reliable and safe operation of an SPM terminal and its components it is
important to perform inspection and
routine maintenance tasks on a regular basis.
This section provides
guidelines for setting up inspection schedules and procedures for CALM and SALM
type SPMs and describes the maintenance tasks which should be performed during
5.1 INSPECTION SCHEDULES
The scope of the Inspection Schedule and the frequency of the
inspection of individual components should be based on the best available
information concerning the SPM equipment and the particular conditions at the
SPM and should be modified on the basis of actual operating experience.
Care should be taken during inspections, including when
diving, to ensure that the SPM is
gas free in all areas, including the well of the buoy.
The following schedules for pre‑berthing inspection and
weekly, monthly half‑yearly and yearly inspection are recommended as a
guideline. The scope and frequency can be altered to suit the requirements of
individual terminals. Reference should be made to the manufacturer's manuals
for specific details.
inspection as described in Section 4.1.1 is presented here in schedule format
for the sake of completeness. Pre‑berthing inspection is performed
primarily to ensure that no damage has occurred to the components of the SPM
system since the last inspection or berthing. Circumstances at the terminals,
such as high berth occupancy, may ~e the cause for performing this inspection
on a daily
Weekly, monthly, half‑yearly and yearly inspection
schedules, and the associated maintenance, are intended to reduce the incidence
of component failure and costs resulting from unscheduled down‑time. As a
result, the life of the SPM facility and its components can be increased and
its reliability improved.
The following inspection schedules list activities common to
both types of SPM except where otherwise stated. Items requiring divers are
(See figure 10.1)
• Check for oil spillage or leaks, whilst at the normal
• Check that trim and freeboard of buoy are correct.
• Board buoy and check:
‑ Mooring connections.
‑ Security of hatches.
‑ For signs of damage to buoy.
- Hose connections. CALM ONLY
- For security of pipework. CALM ONLY
- For signs of leakage from product swivel, rubber expansion
pieces, or other piping
components. CALM ONLY
‑ That valves are operable and in the
appropriate position. CALM ONLY
‑ Pressure gauge readings. CALM ONLY
‑ For unusual noise from bearing or product
swivel, or loss of free movement. CALM ONLY
‑ Telemetry systems
‑ Lights are functioning correctly.
Inspect hawsers and pick‑up lines for damage and
Inspect floating hoses along their
length for damage,‑leakage and fouling whilst at the normal working
pressure (see 6.2.1).
Inspection of double‑carcass hose should be in
accordance with the manufacturer's guidelines.
In addition, the condition of the connections between the pick‑up
ropes and the chafing chains, the chafing chains, chain support buoys and
connecting links, hose pick‑up arrangements and tanker rail hoses should
be checked. These checks should be performed by inspection from a launch prior
to berthing, and subsequent visual checks made from the tanker by the berthing
master or his assistant after the tanker is moored.
Perform all checks in the
pre‑berthing inspection schedule.
Board buoy and perform routine lubrication of:
Main bearing assembly.
Surface fluid swivel
Note: Power greasing is recommended. CALM ONLY.
Sound buoy compartments for leakage.
Check operation of bilge pumps if fitted.
Check buoy fendering for
Check centrewell for contamination. CAUTION: Refer to Section
6.1.2 Safety Precautions. CALM ONLY.
Open bearing cavity drain plugs, rod out and monitor quantity
of water. CALM ONLY.
Check condition and lubrication of bogey wheels system. (For CALM's with bogey wheels only.)
Perform all checks in the weekly inspection schedule.
Lift mooring equipment onto deck of maintenance boat and
Mooring hawsers and hawser‑floats (see 6.2.2).
Chafing chain and check
for wear (see 6.2.3).
Chain support buoy.
Connecting chains and
Pick‑up ropes and
Lift tanker rail hose onto deck of maintenance boat, or
alternatively, inspect by divers, and check:
Tanker rail hose.
Butterfly valves if
Board buoy and perform the following tasks:
‑ Check operation of all valve actuators and
‑ Check all electrical systems.
‑ Check battery boxes are dry and that seals
are in good condition. check electrolyte level and
charge or replace batteries as required.
Perform diver visual inspection of submarine hose strings
including floats, buoyancy tanks, etc. Measure hose configuration and correct
as required. (DJ
Clean marine growth from all anodes. Anodes should be replaced
if more than 75% consumed. (D)
Attach strop between turntable and launch, tend hoses and
slowly rotate turntable assembly through 360' and listen for bearing noise.
Check for hard spots or sluggishness. CALM ONLY.
Check that bearing protection system is intact on both sides
of the bearing. CALM ONLY.
Open bearing inspection plates and check for water. CALM ONLY.
Inspect surface fluid swivel assembly and adjust bolts for tightness and record adjustments.
Measure chain angles and chain weardown under buoy and adjust
as required. CALM ONLY. (D)
Inspect perimeter of mooring base for signs of scouring of
seabed, and anchor piles for signs of motion. Remove debris. SALM ONLY. (D)
Inspect submarine fluid
swivel assembly for signs of leakage. SALM ONLY. (D)
Inspect base universal
joint for signs of wear and security. SALM ONLY. (D)
5.1.4 Half Yearly
Perform all checks in the monthly inspection schedule.
Perform an in‑situ pressure test in accordance with
OCIMF Guidelines for the Handling, Storage, Inspection and Testing of Hoses in
Inspect inside of buoy compartments for corrosion and damage.
Examine rubber manhole seals and replace as required. CAUTION: Refer to Section 6.1.2 Safety Precautions.
Repair minor damage to paintwork according to paint
Measure chain weardown at
seabed. CALM ONLY. (D)
Check anchor piles, or
anchors, and anchor chain connections including joining shackles where accessible.
Check PLEM. (D)
Check surface fluid swivel. For procedure see Section 5.2.1. CALM ONLY.
Check surface piping and expansion joints. For procedure see
Section 5.2.2 CALM ONLY.
Check submarine main
swivel. For procedure see Section 5.3.1 SALM
Check anchor leg. For procedure see Section 5.3.2 SALM ONLY. (D)
Inspect condition of submerged portion of fenders. SALM ONLY. (D)
Inspect condition of flooding valve. SALM ONLY.
Perform all checks in the half‑yearly inspection
Perform complete inspection of cathodic protection system. The
anodes should be cleaned to ensure that they provide maximum protection and
anodes should be replaced if 75% or more has been sacrificed. (D)
Remove sand and silt from
mooring base and/or PLEM. (D)
Inspect selected areas of the
hull for wall thickness.
Check surface fluid swivel oil seals and replace as required. CALM ONLY.
Check surface fluid swivel drive plate for wear and distortion.
Inspect selected areas of the pipework for wall thickness. CALM ONLY.
Check main turntable bearing. For procedure see Section 5.2.3 CALM ONLY.
Check anchor chains and anchor
or anchors piles. For procedure see Section 5.2.4 CALM ONLY. (D)
5.2 INSPECTION PROCEDURES
FOR CALM SYSTEMS
Surface Fluid Swivel
Pressurise system, check swivel for leakage
of crude oil, product or lubricants.
Remove test plugs and check for leakage.
Rotate unit and listen for bearing noises from structure close
to bearings using an engineer's stethoscope or similar instrument.
Check freedom of rotation of swivel.
Check swivel drive assembly.
The oil seals of the central swivel should be examined and
renewed if damaged or as per manufacturer's instructions. It may be desirable to renew the seals even
if the swivel has given trouble‑free service. The correct procedure for
replacing seals should be in accordance with the manufacturer's instruction
book. All bolting of the central swivel should be checked for tightness.
Surface Piping and Expansion Joints
Pressurise the total pipework system
and check all flanges and valve actuators for leakage.
Check for excessive movement of
pipework in pipe clamps.
Check pipe clamp structures for signs
of cracks and distortion.
Check condition and alignment of
expansion joints while pressurised.
The rubber expansion joints should be
examined internally and replaced if the lining is found to be damaged.
5.2.3 Main Turntable Bearing
Check for noise and free rotation:‑
‑ Attach strop to
turntable and mooring launch and slowly rotate turntable through 360'.
‑ Repeat rotation
check in reverse direction.
‑ Record position
of turntable if any sign of jamming or any noise occurs.
‑ Annually three
grease samples of 250gms each shall be taken at the bottom part of
the bearing. These
samples, as well as a sample of fresh grease, should be analysed for:
‑ Iron content mg/kg
‑ Chromium content mg/kg
‑ Magnesium content mg/kg
‑ Water content mg/kg
long as the iron content remains below 25,000 mg/kg, there is no need to
replace the bearing. According to bearing manufacturers, an iron content above
25,000 mg/kg will accelerate deterioration of bearing and consequently
preparations should be made to change out the bearing. In case results from
grease analysis should raise concern regarding the condition of the bearing,
axial and radial weardown measurements are recommended. Wear in the bearing
track system will result in increased internal clearance and in settling of the
upper companion bearing structure. Internal bearing clearance can be measured
Measure axial weardown:
- Remove the lower casing
from the bearing ring.
- Rig four jacks spaced
equidistant on bulk head location, this to avoid deformation in bearing
In case of a six
anchor leg buoy, 3 jacks should be used.
- The total capacity of
jacks should be sufficient to safely raise the turntable.
- Four dial gauges
should be placed in between each jack underside of the exposed ring.
- Each dial gauge
should be preset to zero reading.
- The dial gauge
measurements should be plotted against the hydraulic pressure of the 4 coupled
to be taken
at approx. 5 tonnes,
10 tonnes, 15 tonnes, etc., up to 50 tonnes, depending on weight of turntable.
- Measurements should
be recorded whilst jacking up and lowering the turntable. The maximum
permissible axial bearing
play depending on size and type of bearing is
approx. I mm. Manufacturer's recommendations should be consulted for
more precise value.
- Remove inner protection
- 12 x 30' sections to be
marked for positioning jacking procedures around periphery of turntable structure.
- Position No.1 to be set
at the centre of the outboard pipework.
- Special tool for
jacking to be positioned between turntable centre wall and central pipe, below
central pipe bearing
in horizontal position. Horizontal force should
be max. 20 tons.
- 2 dial gauges to be
fixed on turntable and set against the buoy body.
- No.1 dial gauge to be
set opposite and adjacent to jacking position readings in the minus direction.
- No.2 dial gauge to be
set on turntable against buoy body at 1800 to dial No.1 for readings in the
positive direction, in order
to record relative horizontal movement between
buoy body and turntable.
- Procedure for reading
set at No.1 position is statutory for all 12 x 30' readings.
- The maximum permissible
radial bearing play depending on size and type of bearing is approx. 0.5 mm.
Manufacturer's recommendation should be consulted for more
- Compare results with
any previous reports. Annual test should show a gradual increase as wear
occurs. The bearing
should be replaced when the clearances exceed tolerance limits
given by the bearing manufacturer.
- Measure clearance
between wheels and rails at eight different points.
- Check the condition of
the top and bottom rails and the wheels for signs of wear and flattening.
- Check the security of
ties between the rotating arms and arm connector pins.
- If clearances exceed
the maximum allowable stated in the manufacturer's manual, it will be necessary
to replace worn parts
or take other
corrective measures. (For CALM's with bogey wheels only.)
5.2.4 Anchor Chains and
Anchors or Anchor Piles
Check anchor chains. (D):‑
- Disconnect anchor
chain pendants one by one from buoy.
- Lift the top section of each chain out of the water and
inspect chain, chainstoppers and ancillary equipment
From the rate of
wear, he probable life of the chains can be estimated and a chain maintenance
- Anchor chain links should be replaced when any chain link
diameter is reduced due to wear to 80% of it's original diameter.
Check anchors or anchor
‑ Measure the distance from the crown of the
anchors to the marker pegs to detect drag. Re‑adjust anchor positions as
required. Record anchor positions.
‑ Check areas of the seabed immediately around
anchors or anchor piles for signs of scouring.
‑ Anchor flukes and at least half of the crown
should be embedded. Jet anchors to sink deeper as required.
INSPECTION PROCEDURES SALM SYSTEMS
5.3.1 Submarine Main Swivel
Attach strop to end of floating hose string and secure to
Tow hose string around buoy to rotate swivel through 360'.
Check that the swivel rotates freely. (D)
Repeat rotation check in reverse direction. (D)
Pressurise system. Check all valves and flanges for signs of
leakage. De‑pressurise system. (D)
Measure and record
clearance between bumper rails and bumpers if applicable. (D)
Inspect hose arm
structure for signs of damage and distortion. (D)
5.3.2 Anchor Leg
Measure chain and shackle
components for weardown. (D)
Check chain swivel for
free rotation. (D)
Inspect buoy and base
universal joints. (D)
Measure and record
progress of wear on buoy and base universal joints. (D)
between bar universal joint and main swivel. (D)
Check and record
siltation level or scour around base. (D)
Inspect bolted connection
of main swivel assembly to base structure. (D)
Section 6. 0
Maintenance and Major
Routine or preventative
maintenance is essential if sudden failure of SPM components and the resulting unscheduled downtime is to be avoided.
This section provides
guidelines for the planning and performance of maintenance tasks.
Maintenance of an SPM facility may involve downtime and is
therefore an expensive operation in terms of lost production. Lost time can
effectively be reduced by initiating a planned schedule of work, which takes
into account long lead items and the availability of facilities and equipment,
well in advance of the actual overhaul period. All work should be carried out
utilising a permit to work system.
The frequency of maintenance will vary depending on particular
conditions at the SPM facility. Maintenance schedules should be based on
manufacturers recommendations and the deficiencies and trends observed during
regular inspections. The inspection schedules suggested in Section 5 and the
records as outlined in Section 10 should give a good indication of the
condition of the SPM and its components.
6.1.1 Factors Influencing Planning
Consideration should be given to the following factors when planning
Age and condition of the SPM and its components.
Scheduled shut‑downs of other facilities, e.g. platforms
or shore facilities.
Replacement parts required and delivery lead times.
Special tools required and availability.
Estimated total time required for completion of work.
Cost penalties in the event of overrun.
Towing requirements and availability.
Heavy lift requirements
offshore and onshore.
requirements and support facilities. 6.1.2 Safety Precautions
Safety is of paramount importance during maintenance work. The following
precautions are recommended:
Buoy compartments, including the centre well, must be
ventilated. Before entering check that compartments are gas free and that sufficient oxygen is available. Persons
entering should wear a hard hat and a safety harness and should be attached to
a 'lifeline'. An assistant should standby tending the other end of
the line. Oil spillage in work areas should be properly cleaned up. When
compartments are being inspected the turntable should be locked to ensure that
access hatches are clear at all times.
Hot work should be in accordance with a hot work permit
system. This system should be operated by a responsible person who will ensure
that the appropriate areas are gas free and who will impose the particular restrictions required to ensure
Due attention should be paid to earthing points when electric
arc welding is carried out. IT IS
ESSENTIAL THAT WELDING EQUIPMENT IS NOT EARTHED ACROSS THE BEARING. Stray
electric currents can cause severe damage to turntable bearing elements or
Lines are usually purged with sea water prior to commencing
any work on the product transfer system.
APPLICABLE TO ALL SYSTEMS
6.2.1 Replacement of SPM Hoses
In general SPM hoses should be brought ashore and tested as
part of a preventive maintenance plan. The frequency of onshore testing will
vary depending on operating and environmental conditions at the terminal.
Testing of hoses periodically and maintaining detailed records will assist in
determining change out frequency. Certain types of ‑hoses such as First
Off the Buoy and Tanker Rail hose tend to have a lower service life than other
Recommended procedures for the replacement of CALM type SPM
floating and submarine hose strings are shown in Figure 6.1 and 6.2
respectively. Procedures for the replacement of SALM type SPM hose strings are shown in Figure 6.3.
6.2.2 Replacement of Mooring Hawser and Pick‑
Up Rope Assemblies
At the present time no universal method exists for determining
the remaining useful life, or residual strength, of a used mooring hawser. It
has been established that cyclic loads, physical damage, and ageing can
contribute to loss of strength.
At most SPM terminals one or more of the following methods are
used to determine when mooring hawsers should be replaced:
Evidence of severe external abrasion especially near splice
locations and eyes.
Evidence of severe abrasion between strands.
- A significant
number of strands cut or pulled out.
- Evidence of
damage to the inside core of the hawser such as necking.
Number of Ships/Length of Service
‑ Limits for maximum service life expressed as a number
of ships or months unless visual inspection results in earlier retirement.
A combination of visual inspection and number of ships/length of service is
probably the best method to use until more precise methods are developed. Break
testing of used hawsers with recorded service histories may provide a rational
basis for adjusting replacement criteria.
6.2.3 Replacement of Chafing Chains
Chafing chains should be replaced when any chain link diameter is reduced,
due to wear, to 90% of its original diameter.
6.3 INFORMATION PARTICULAR
TO CALM SYSTEMS
6.3.1 Replacement of Main
during rotation, signs of jamming or other signs of wear indicate a faulty
bearing. Bearing failures may be due to any of the following reasons:
Overloading in excess of the design limits caused, for
example, by vessel collision or excessive hawser loading.
electrical current caused by incorrect earthing during welding operations.
protection against water ingress.
failed bearing is dismantled, it is important to inspect all surfaces and
identify the root cause of failure. If possible, improvements should be made to
general, a turntable roller bearing requires the exchange of the entire
bearing. In cases where the bearing is mounted by a metal‑to‑metal
facing and only machining of the horizontal faces is required. the repair may
be undertaken offshore. Overhaul of bearing resin surfaces must be undertaken
on a barge or onshore where controlled conditions and facilities are available.
the removal of the turntable and the old bearing the first stage in replacing a
conventional bearing is to place the new bearing onto the support ring of the
The bearing should be levelled
and centred by the adjusting screws and guiding pins, checking that:
Its centre is
concentric to the axis of the
central swivel unit.
plane is perpendicular to the axis of the central swivel unit.
The bearing is within flatness tolerances as
specified by the manufacturer.
applicable, the foundation resin should be applied after alignment. The bearing
fastening bolts can be installed and pre‑tensioned after a 24‑hour
resin curing time. Pre‑tensioning of the fastening bolts to values
specified by the manufacturer is preferably done by hydraulic tensioning jacks
although a torque wrench may be used where access. is a problem. It should be
noted that the torque wrench method is far less reliable.
installation, the attendance of a bearing specialist is recommended. In the
second stage the turntable should be placed on top of the buoy onto adjusting
screws. The bearing grease holes must correspond with the connections in the
support structure. The same procedure for the alignment, grouting and
fastening of the bearing to the buoy body should be followed. Grease pipes
should bc checked and grease lines connected. The bearing should be greased
whilst rotating the turntable until a grease collar appears at the seals.
6.3.2. Surface Fluid Swivel
Dismantling of the surface fluid
swivel and the replacement of seals should only be attempted in‑situ in
good weather and calm seas.
Dismantling may be required if product or contaminated grease
is seen to be leaking from the swivel. From the source of the leak it will be
possible to decide whether partial or total dismantling is required. Leakage of
uncontaminated grease may be due to excessive lubrication. In this case
dismantling is not required.
Renewal of seals should be performed with reference to
manufacturer's manuals. Before any component is removed, reference marks should
be made on convenient non‑critical surfaces. Upon removal, all components
should be cleaned and inspected and all defects noted. All machined surfaces
should be coated with grease and critical surfaces protected.
6.3.3 Turntable and Ancillary Equipment
During periods of routine maintenance, a thorough inspection
of all the components on the turntable assembly should be made. Particular
attention should he paid to the condition of:
All flexible joints in the turntable piping.
Piping, pipe supports and valves.
Navigation aids and electrical system.
Turntable brake if applicable.
Chain tensioning and lifting equipment if applicable.
Overboard pipe swivels, if applicable.
Depending on the results of the inspection, repairs and
renovation, including any cleaning and repainting of steel surfaces, should be
6.3.4 Anchor Chains
The progress of wear on anchor chain pendants and joining
shackles can be judged from previous results of inspection checks for weardown.
An assessment of the need for the replacement of chain shots and other fittings
such as shackles can then be made (see 6.2.3).
It is of paramount importance for the proper working of the
SPM facility that the buoy is correctly positioned with respect to the end of
the submarine pipeline and that the anchor chains are correctly pre‑tensioned.
The position of the buoy, should then be checked with a plumb
line against a fixed reference point on the seabed or by using other suitable
instrumentation such as electronic position fixing systems at slack tide. The
pretension in the chains should be monitored by measuring the inclination of
the chains to the horizontal using an angle indicator as shown in Figure 6.4.
The buoy position and the measured angles should be recorded for comparison
with design values and subsequent measurements. Any substantial deviations
beyond design tolerances should be corrected as soon as possible.
If the angle is too great then the chain
pendant is too slack. This may be due to the following causes:
Straightening of pendants under loads greater than those
applied during laying.
Dragging of anchors.
If the angle is too small there is too much tension in the
chain pendant. This may be caused by settling of the pendant in the mud. This
situation needs prompt attention, because the available lifting capacity may be
insufficient to lift the chain from its housing if it is left too long. Marine
growth or corrosion may prevent the chain from being lifted from its housing
and therefore chains should be lifted regularly.
The following tolerances in the angle of pretension are
normally permissible for six or eight pendant systems:
Between two chains at a watertight bulkhead the difference not
to be more than two degrees.
Between any two chains not more than four degrees.
The average inclination
of all chains should lie between the design angle and the design angle minus two
degrees and the inclination of no chain should exceed the design angle plus two degrees.
Minor overhauls may be possible with the buoy in‑situ,
but major overhauls will require the buoy to be dry‑docked The interval
for major overhaul will depend on terminal usage but can be assumed to be in
the region of 10 years.
In preparing a suitable work site, such as a drydock or other
area with crane lift capacity, the manufacturer's layout drawings should be
carefully studied. The blocks on which the hull will rest must be positioned so
that the hull is supported on the watertight bulkheads, and the blocks must be
of sufficient height to allow clearance for the cargo piping extending below
the bottom and to allow painting of underside platework. Care should be
exercised to ensure that the anodes on the bottom of the hull are kept clear of
the docking blocks.
Removal of the buoy from the terminal site can be achieved by
either lifting the buoy onto a barge or by towing to a dry dock facility.
6.3.6 Buoy Towage
During towing, a minimum unobstructed water depth of 4.5 m is
normally required but this should be checked against the manufacturer's
drawings. Towing cables should never
be attached to any part of the turntable assembly. Towing cables should
incorporate a stud link chain to fit chain stoppers on the buoy. A typical
towing configuration is shown in Figure 6.5.
Unless damage has occurred or leaks or excessive corrosion are
observed, it should not be necessary to remove the PLEM or any of its
components from the sea bottom. Other maintenance is limited to regular checks for bolt tightness.
6.4 INFORMATION PARTICULAR TO SALM SYSTEMS
Minor leg maintenance may be possible while the SPM is in‑situ.
Major maintenance of the buoy, anchor leg and main swivel will require the
components to be brought ashore for overhaul. Procedures for the removal of the
buoy and anchor leg and for the removal of the main swivel are described in
detail in Sections 6.4.1 and 6.4.2. Procedures for replacement are essentially
the reverse of those for removal.
6.4.1 Buoy Body and Anchor
Wear in excess of manufacturer's tolerances in the anchor
chain, chain swivels or universal joints, will require the anchor leg and buoy
body to be removed. Damage to the buoy body or the need for a major overhaul of
the buoy, will also require the removal of both the buoy and the anchor leg in
one operation. The following procedure is a guideline:
Remove the mooring assemblies.
Tie up the buoy to the
anchored crane barge or boat. Block up the base universal joint so that it will
remain in a vertical position when the chain is slack as shown in Figure 6.6 ‑Sequence
Check that all hatches
are closed in the upper deck and the lower deck inside the buoy. Remove plugs
from the lower flooding valves and connect air hoses to the vent pipes in the
top deck. Connect the hook to the mooring bracket on the buoy. Open the buoy
flooding valves slowly to flood the lower compartments and control the flooding
of the buoy by checking water levels through the sounding pipes in the deck to
ensure even ballasting. Continue until the chain becomes slack and close all
valves and re‑insert plugs in all sounding pipes and vents.
Connect an auxiliary hook
to the chain near the base universal joint. Mark the position of the universal
joint for reassembly. Remove the locking pin from the shackle at the base
universal joint. Attach a safety sling to the shackle pin from a point near the
top of the chain and drive the pin out using a hydraulic jack.
Remove the shackle from the base universal joint and support
the weight of the chain on the auxiliary hook as shown in Figure 6.6 ‑
Sequence 2. Move the buoy clear of the base and open the lower flooding valves,
connect air hoses to a compressed air supply of maximum 25 psi and start to
blow water out of the lower buoy compartments. Assistance in controlling the
buoy during de‑watering is obtained by partially supporting the buoy
using the crane and lashing the buoy to the barge as shown in Figure 6.6 ‑Sequence
The buoy and anchor leg may be lifted onto a barge, towed by
the anchor leg to shore or tied in a safe mooring place in ballast as shown in
Figure 6.6 ‑ Sequence 4.
The anchor leg including the base and buoy universal joints
and the chain swivel should be thoroughly checked for wear and freedom of
movement. The anchor leg should not be disassembled unless wear or lack of free
movement is evident. If necessary, servicing should be performed under the
supervision of qualified specialists.
The anchor leg connection to the buoy and the buoy hull should
be inspected for signs of damage internally and externally. Fenders should also
be checked for damage and security of fastening.
6.4.2 Submarine Main Swivel
and Hose Arm Assembly
Lack of free rotation or jamming of the swivel or leaks which
cannot be corrected by the tightening of bolts will require the swivel to be
taken onshore for overhaul. Removal of the main swivel will require the prior
removal of mooring assemblies, the buoy and anchor leg, all connecting
hoses and possibly the hose arm assembly. Reference to
manufacturer's manuals should be made to establish the extent of dismantling
required prior to removal. The following procedure is a guideline:
Remove mooring assemblies and submarine hoses.
Remove buoy body and anchor leg.
remove the hose arm assembly by shoring up from the base and flooding the
buoyancy tanks. Mark flanges so they can be re‑assembled in identical
positions. Attach the crane hook slings before removing any flange bolts or
components. Lift the hose arm assemblies to the surface, provide blanks to
protect bare flanges. If the hose arm assembly is left in position it should be
stabilised by adjusting the water level in the buoyancy tanks. During lifting
from the base to the surface it may be necessary to slowly open the vent valves
on the buoyancy tanks to reduce the air pressure.
Remove all sand,
silt and debris from the mooring base in the vicinity of the connections
between the base pipework and the main swivel. Disconnect all pipe connections
from the main swivel until it is free to be lifted. Mark all flanges for re‑assembly
and provide blanks to protect bare flanges.
Attach the crane
hook to the base universal joint and disconnect the main swivel from the base
as shown in Figure 6.6 ‑ Sequence 5. Lift the main swivel slowly to avoid
damage to the base piping. When the swivel breaks the surface, an auxiliary
hook should be connected to the hose arm to provide stability before lifting
onto the barge as shown in Figure 6.6 ‑ Sequence 6.
Renovation of the main swivel is a specialised task and should
only be conducted under the control of qualified specialists.
Maintenance of the base structure itself is normally limited
to inspection and the necessary remedial work for:
Silting or scouring.
Corrosion and the condition of the cathodic protection
Maintenance of the PLEM structure will be the same as for the
base. If jumper hoses are used, periodic removal, testing and replacement of
the hoses will be required.
Section 7. 0
Diving and ROV Services
It is the
responsibility of the owner or operator of an SPM to ensure that all underwater
intervention operations carried out by divers or remotely operated vehicles
(ROV) are undertaken in accordance with relevant legislation, standards and
guidelines and in such a way as to ensure that persons involved are not exposed
to risks to their health and safety.
times the integrity of the facilities should be maintained and proper regard
paid to conservation of the environment.
of this chapter is to give guidance on the fundamental principles of the
management of underwater intervention operations, an outline of the methods of
intervention which may be employed, and the issues to be considered in
selecting the most appropriate method for the particular requirement and conditions.
7.1.1 Minimise the Need for Underwater Intervention
Carrying out work underwater is in all respects the most
disadvantageous option, and every effort should be made to design out the need
for it. This may be achieved in a variety of simple ways, e.g., by placing,
wherever possible, a component which may need periodic maintenance or repair
clear of the water on the SPM, or installing surface‑controlled
hydraulically‑operated valves in place of manually operated valves
7.1.2 Minimise Exposure to Hyperbaric Pressure
Manned diving in a hyperbaric environment involves a unique
combination of occupational health and safety issues that requires effective
management and control at all levels. the use of remot6 intervention technology
will negate those issues. As a matter of principle manned diving should only be
used where no other method is practicable and cost‑effective.
7.1.3 Contract all Underwater Work as a Service
It is the responsibility of the diving or ROV services
contractor to undertake the work as specified in the contract safely and
effectively, in accordance with Local and National Regulations. Where Local
Regulations are either not in place, or are considered to be insufficiently
stringent, the SPM owner or operator should specify regulations and standards
with which the contractor is required to comply. The contract should specify,
The scope of the work to
The operational and environmental conditions
in which the work will be undertaken, including the presence in the vicinity
ofthe SPM of any substances hazardous to health;
Particular requirements for equipment and tooling, e.g. surface supplied
diving equipment, ROVs, underwater
cleaning and inspection equipment etc.
Particular regulations and standards which are required to be complied
Local safety requirements, e.g., no fishing in the vicinity of the SPM.
7.1.4 Selection of
Contractors should be selected on the basis of their technical capability,
record of safety in underwater operations and having in place appropriate rules
and procedures, including emergency procedures and safety management systems.
7.1.5 Inspection and Audit
Personnel, equipment, certification procedures and controls should be
inspected and audited against the requirements of the contract prior to
commencement of the work. Additionally the proper functioning of critical
systems should be demonstrated and emergency procedures exercised.
In order to ensure that all systems and local conditions are safe for the
method of underwater intervention being employed, permit to work‑
procedures should be enforced.
7.2 ENVIRONMENTAL SAFETY CONSIDERATIONS
State, Swell and Currents
motions and underwater currents and tidal streams imparted to the SPM can make
it difficult for either a diver or ROV to carry out work on, any part of an SPM
and it's associated mooring and riser systems.
When manned diving is employed the effect of SPM or diving
support vessel motion should be taken into account when determining whether
conditions are suitable for diving operations to be carried out.
7.2.2 Surface Visibility
In conditions of poor surface visibility, in addition to
recognised navigational hazards, account must also be taken of the ability of a
surface rescue vessel to locate and recover a diver who may surface in an
emergency and be swept away from the SPM. Diving operations should be suspended
if environmental conditions make this a possibility.
7.3 OPERATIONAL SAFETY
7.3.1 Over‑side Loads and Working
Materials and equipment must never be handled over the side
while divers are in the water. Where this is unavoidable, e.g., it is required
in support of the diving operation, all materials and equipment should be
handled clear of the diver's position and secured against being dropped before
being passed over the side.
Objects dropped into the water close to a diving operation create a serious
risk to divers.
7.3.2 Surface Vessel Movements
Whenever diving operations are in progress surface vessel movements in the
vicinity of the SPM are to
be strictly controlled, and no vessel is to go alongside either the SPM or
the diving support vessel, without prior approval or permission of the person
controlling the diving operation.
7.3.3 Diving on Internally Pressurised Pipelines
Divers should not be permitted to dive on pipe‑lines which are
undergoing an internal pneumatic test. When a pipeline is suspected of being
damaged or defective, divers should not approach to within 100 metres of the
line until it's internal pressure has been reduced to less than 80% of the
highest pressure to which it has been subjected
since the defect was first suspected or discovered.
Fishing should not be permitted from or in
the vicinity of an SPA
7 4 MANNED DIVING SAFETY
7.4.1 Pressure Related Illnesses
Decompression sickness is the most widely‑known form of
pressure‑related illness. Other pressurerelated illnesses can occur at
shallow depths as the gas in ihe body undergoes a significant change in volume
over a lesser variation in depth. In such cases it is imperative that treatment
should be given with the minimum of delay. In order to do this the diving
contractor should have in place arrangements whereby divers can be transferred
safely to a recompression chamber for therapeutic treatment.
7.4.2 Provisions for Treatment of Pressure Related
When diving for whole or part of the work is at depths greater
than 10 metres it is recommended that a two‑compartment recompression
chamber should be available 6n site. When all diving is shallower than 10
metres a recompression chamber should be available within a maximum of 2 hours
travelling time from the work site. In the latter case, if the recompression
chamber is not owned by the diving contractor he must have in place a firm
arrangement with the owner for it's use in an emergency.
7.4.3 Diver Entering and Leaving the Water
A safe method of entering and leaving the water is to be
available to the diver, including a method of recovering an incapacitated or
unconscious diver. In some circumstances this may require the provision of a
diver‑deployment basket, in which case separate provision is to be made
for the stand‑by diver and there is to be both a primary and secondary
method of recovering each basket.
7.4.4 Head Protection
In order to protect the divers' head from impact with any part
of the SPM system due to relative motion, some form of head protection is
required. This is best provided by using hard helmets.
7.4.5 Use of Closed‑Circuit.Television
A head‑mounted CCTV camera with surface monitor, where
available, can provide useful information to both the diving supervisor and the
7.4.6 High Pressure Water. Jetting Equipment
This equipment can emit high levels of noise, and when divers
are required to use it then ear‑protection is required.
7.5 USE OF HYPERBARIC
7.5.1 Surface Oriented Diving
The nature of their service usually implies that SPMs will be
located in water depths shallower than 50 metres. At these depths and for the
routine type of work required on SPMs surface‑oriented diving may be
used. Therefore this method of manned diving only is addressed. In deeper
water, or when there is an intensive programme of heavy construction, repair or
abandonment work , to be undertaken, saturation diving may be required, and
specialist assistance should be sought.
7.5.2 Self Contained Underwater Breathing Apparatus
This equipment generally lacks three elements which are
considered to be essential to the safe conduct of commercial diving:
Renewable supply of breathing gas. The amount of gas used by a
diver depends on the depth at which he is working and his work‑rate.
Divers frequently fail to monitor their own gas usage, and any one of them may
find, himself with only his emergency supply left and unable to s4ff#pe safely
in ‑a controlled manner.
Depth monitoring. It is imperative that thi diving supervisor
knows the maximum depth at which a dive has taken place, and to be able to
control the depth of a diver during decompression in the water. It can also be
a working guide in demonstrating that the diver is at the correct depth for a
mid‑water work site.
Voice communications. This is an indispensable tool for the
diving supervisor. It enables him to monitor the safety of the diver by
listening to his breathing pattern and hearing any sounds of distress or calls
for help. It also enables him to give precise work instructions to the diver, and, to answer any queries the diver may have regarding the work.
SCUBA may be used for commercial diving operations:
When the diving services contractor can demonstrate in writing
that, it's use ‑under specific circumstances would be safer than using surface‑supplied equipment.
In water depths shallower than 10
For light work, e.g. observation
and visual survey.
7.5.3 Surface Supplied Breathing Apparatus (SSBA)
This is considered to be the safest method for commercial
diving because it permits all aspects of the dive to be monitored and
controlled at the surface by the diving supervisor, including renewal of the
divers' supply of breathing gas.
It comprises a surface control panel for supplying breathing
gas, a hard‑line communications link and depth measuring system, all
linked to the diver via an umbilical. The divers' personal equipment includes
an emergency supply of breathing gas.
7.5.4 Light‑Weight SSBA
SSBA is often considered to be too cumbersome for use on an
SPM, particularly for jobs of a short duration. However it is possible for the
diving services contractor to assemble a compact version b% making‑up a
small portable control panel, and utilising approved breathing gas storage
cylinders to supply the required amount of breathing gas for the job. The
breathing gas supply system should be arranged so that a reserve gas supply is
always available on‑line to the diver except, when the main supply is
exhausted and the reserve put in use, the empty cylinder may be temporarily
removed to be
replaced by a full one. The size and number of cylinders
required would depend upon the water depth, duration of the dive and whether
the work is heavy or light.
Such systems should continue to meet the basic requirements of
surface monitoring of the gas supply and divers' depth, and a voice
7.5.5 Use of NitrogenlOxygen (Nitrox) Breathing Gas
Air is the most commonly‑used breathing gas for divers
at depths down to 50 metres. However in the 30‑50 metre depth range it
requires a significant amount of time to decompress a diver such that the time
required to decompress can be much greater than the time spent working. It can
also cause nitrogen narcosis in some divers, impairing their ability to work
safely and effectively. A way of mitigating these effects is to use a nitrox
mix where the level of oxygen is greater than in air. The concomitant reduction
in the level of nitrogen reduces the time required for decompression, and reduces the possibility of
nitrogen narcosis occurring.
There are, however, attendant risks associated with the use of
nitrox. The partial pressure of the oxygen must never be permitted to exceed
1.5 bar, otherwise the diver may suffer oxygen toxicity. At the best this may
lead to temporary lung impairment, it may result in the diver suffering
convulsions, and at worst it can be fatal.
The diving services contractor must be experienced in the use
of nitrox as a breathing gas, as must all of the diving supervisors and the
divers. The contractor will advise the SPM owner or operator on the
implications of using this technique, and will determine the safe level of
oxygen for a nitrox mix according to the maximum working depth of a dive.
7.5.6 Diving Team Size
The absolute minimum number of people required in a diving team
is three: a diver, stand‑by diver and supervisor. However this will only
permit two consecutive no‑decompression dives in shallow water and only
one dive, limited in duration by the decompression requirements, at deeper
depths. Additional team members will be required to operate plant and
equipment, and dive for more extensive operations.
7.5.7 Diver Competency
All divers should have undergone theoretical and practical
training in commercial diving, including the operation and maintenance of all
types of plant and equipment to be used and the application of routine and
therapeutic decompression procedures. They should also be certified as being
medically fit to undertake commercial diving. Diving supervisors should be
qualified commercial divers experienced and knowledgeable in all aspects of
diving and the work which is to be undertaken. Preferably they should have attended a formal training course for
commercial diving supervisors.
7.6 USE OF REMOTELY
OPERATED VEHICLES (ROV)
7.6.1 R 0 V Capabilities
ROVs come in a range of types and capabilities, and are
capable of carrying out all inspection work associated with SPMs and, given the
appropriate level of pre‑engineering, a significant range of maintenance
and repair tasks. The effectiveness of ROVs in respect of both their operation
and cost is dependent upon proper planning of the work and provision of the
appropriate tooling to ensure their access to and interfacing with the various
components of the SPM.
Would‑be users of ROV services should be aware that no
ROV can match the dexterity, flexibility and tactile senses of a human‑being
doing the work directly, and consequently an ROV will usually take longer than
a diver to complete many underwater tasks. However a survey of their
availability at the
required location and analysis of the cost benefits to be
realised should be carried out before committing to this method.
7.6.2 Types of ROV
The following sections provide a brief description of the
three main groupings of ROV in order to roughly quantify the equipment
inventory and space requirements of each. With over three hundred different
models available world‑wide it will be appreciate that this can only be a
very broad‑brush guide.
220.127.116.11 Low Cost ROV(LCROV)
These are generally compact systems which may be hand‑carried,
although when deployed in deep waters a simple handling system such as a
powered block will be required. The vehicle fits within an envelope of about
0.5m x 0.5m x 0.5m, typically
weighs <60kg and
requires two people to deploy and operate. Being light‑weight and low‑powered
they are not capable of use
in >Sea State 4 or tidal streams A.5 knots.
They are fitted with a single camera and are mainly used for
general visual surveys and monitoring divers.
18.104.22.168 Observation Vehicles
These vehicles can be used safely in wave conditions up to
about sea‑state 6, and can operate effectively in tidal streams up to
about 0.75 knots. Their power, video quality, and ability to mount additional
stills cameras or light‑weight sensors enable them to be used for light
inspection tasks as well as for diver monitoring and support. Excluding any
tooling packages which may be mounted on an ROV, the basic components of a
total ROV system which need to be taken into account when planning the mobilisation
of a system are:
Typical system component dimensions and weight (in air):
ROV ‑ 1.0metre x
0.6metre x 0.6metre < 90kg
Tether Management System
(TMS) ‑ 1.0metre x 1.0metre, 0.5tons
Deployment skid ‑
3.5metres x 2.Ometres, 6.Otons
Control cabin ‑
5.Ometres x 2.4metres, 10.Otons
Workshop ‑ 3.Ometres x 2.4metres, 7.Otons
22.214.171.124 Work Class Vehicles
These are the larger types of vehicle which, with good
planning and engineering, are capable of undertaking the majority of tasks
performed by divers using either sophisticated manipulators or purpose‑built
tooling packages. However for work on facilities which were not specifically
designed to facilitate ROV intervention it may be necessary either to develop
special engineering procedures for specific tasks, or replace those components
which are required to be maintained or changed‑out b% ROV. These vehicles
can be used safely in wave conditions up to about sea‑state 7, subject to
suitable launch platform, and can operate comfortably in tidal streams of up to
about 1.0 knots. Specifications for system components for the different types
of vehicle in this class can vary significantly at either end of the scale, but
Typical system component
dimensions and weight (In Air):
ROV ‑ 2.0‑2.5metres x 1.0metre x 1.5 metre, 0.5 tons ‑ 2.0 tons
TMS ‑ 2.0 metres x 2.0 metres 2.0 tons
Deployment Skid ‑ 8.0 metres x 3.0 metres, 30.0
Control Cabin ‑ 6.1 metres x 2.4 metres, 12.0
Workshop ‑ 6.1 metres x 2.4 metres, 15.0 tons
Charge Cart ‑ 2.4 metres x 2.4 metres, 2.0 tons
Section 8. 0
This section provides a
general overview of the supporting craft and shore facilities required for operation, maintenance and repair of
SPMs. The design of support craft and shore facilities largely depends on the
phYsical needs of each individual terminal coupled with weather, environmental
and regulatory considerations.
8.1 CRAFT FOR MARINE
8.1.1 Mooring Launches
There is no standard specification for a mooring launch since
the specific conditions at the offshore location will dictate operational and
technical requirements. Sea conditions, weather and distance from shore are
prime determining factors.
The design and location of the superstructure should be such
that it is placed well forward to provide good visibility, a large clear deck
area and should be set inboard to prevent contact with the tanker's side while
The deck configuration should make allowances for bitt spacing
for pick‑up hoses, freeboard to permit safe pick‑up of hoses and
ropes, towing bitt or hook, capstans to assist with hose pick‑up,
openings to safely embark and disembark personnel, and a stowed or recessed
In addition, the following factors should be considered when
selecting a mooring launch for a particular site:
Weather and sea state for normal operations.
Port facilities available.
Distance from shore facilities.
Time on station.
Mooring and hose connection equipment to be carried.
Fendering to permit hawser and hose pick‑up without
Back‑up hydraulic units for valve actuation.
Fuel and water capacity.
Facilities for pumping bilge water to shore.
Exhaust system to
ensure there is no ignition hazard.
Local conditions will dictate hull dimensions. Mooring
launches are typically between 13 and 26 metres in length and 3.5 and 8.0
metres in beam. The horsepower required also depends on the overall duties of
the launch. Most launches, however, fall in the 2 x 200 HP to 2 x 400 HP range.
Other factors such as towing capability and maintenance requirements will also
play a part in final horsepower determination. Consideration should be given to
the water cooling system if problems from fouling by ropes, dirt~ water and
marine growth, etc., are to be avoided.
The total quantity of items carried on board the launch for
mooring and hose handling purposes should be sufficient to cover the equipment
listed in section 4.1.1.
8.1.2 Maintenance Vessels
Terminals with only one SPM can usually perform the required
maintenance with a modified supply or tug boat. Terminals with more than SPM
normally need a specially‑built vessel to cope with the maintenance
workload. A maintenance vessel should be capable of performing the following
Mooring hawser change out.
Floating/submarine hose change‑out.
Maintenance of navigational aids.
Pressure testing of
Repair of SPM system
Removal of marine
Oil spill clean‑up.
The following facilities should be considered for the maintenance vessel:
‑ Service air compressors.
‑ Tugger winches.
‑ Four‑point mooring capability.
‑ Crane with 40 tons lifting capacity over the
working deck and a minimum jib height equal
to a standard single hose length plus approx. 3 metres.
‑ Drain trough for oily water from hose
‑ Slop tank with capacity equal to hose string
volume plus 50%.
‑ Oil water separator.
‑ Beam equal to standard single hose length
plus approximately 3m.
‑ Adequate hose securing points on deck.
‑ Hydraulic and air impact wrenches.
‑ Water jetting equipment if marine growth is
‑ Welding and burning equipment.
‑ Oil spill clean‑up equipment.
Adequate water‑purging pumps, capable of flushing the
Small workshop for
repairing system hardware.
Stern steering station
enclosed in wheelhouse with upward vision.
accommodation to meet all maintenance personnel needs.
Heavy maintenance work, such as lifting the SPM buoy out of the water,
usually requires the use of ~pecial vessels or barge with heavy lift capability.
A maintenance vessel designed specifically for SPM work will normally include
facilities for the complete disconnection of CALM or SALM buoys for towing
ashore if the location allows. Heavy lift equipment is usually required to
replace chain anchor legs, to remove SALM swivels and PLEM assemblies.
Major repair an& maintenance is normally carried out within a weather
window and it is therefore, essential that the maintenance vessel has the
facilities to support personnel engaged in shift work.
8.1.3 Use of Tugs in Operational Support
Tug assistance may be'required at a SPM to maintain a taut mooring, for
example when yawing is a problem or at a tide change. In such cases, a tug or
mooring launch of sufficient size and horsepower should be used.
8.2 SHORE MAINTENANCE
The extent to which dedicated onshore maintenance facilities are required
will be determined by necessity. Determining factors include:
Availability of other
facilities within the area with necessary equipment and skilled personnel.
Number of SPMs.
Frequency of hose string change‑outs.
8.2.1 Yard and Storage
The following onshore facilities are
required to support an SPM operation. The degree of sophistication largely
depends on the number of SPMs operated and the time available to perform
Storage of SPM Spares
Warehouse storage of spare parts is recommended. Warehouse
storage of some spares is necessary since open stowing in severe weather
conditions can cause rapid degradation of some components such as mooring
hawsers, seats, rubber expansion joints, rubber hoses, synthetic chain support
buoys and pick‑up buoys. A sufficient number of spares should be stored
at the shore yard to ensure uninterrupted operation of the SPMs. The quantity
of spare parts required will depend on the service life and delivery lead time
of each replacement part.
Hose Testing, Repair and
Hoses should be tested,
inspected and stored in accordance with the OCIMF publication entitled
'Guidelines for the Handling, Storage and Inspection of Hoses in the
8.2.2 Facilities for Major Overhaul
The SPM operator should own or have access to a crane capable
of lifting the SPM buoy out of the water for a major overhaul, or have access
to dry‑dock facilities. In addition, a barge or sufficient dock space is
required on which to place the SPM buoy while it is being overhauled. A covered
work area is desirable when repairing a product swivel or turntable.
8.2.3 Dock Space for Service
When mooring launches and maintenance vessels are owned or
long‑term leased, consideration should be given to providing permanent
dock space for use when the craft are off‑station. Dock services to be
considered should include water, fuel, electrical power and a slop tank for
A sufficient quantity of spare parts should be available to ensure reliable
uninterrupted operation of the SPNI.
The following recommendations for the quantities of spare parts to be kept
in stock are based on A facility consisting of a single SPM. If the facility
consists of more than one SPM a full spares back‑up will not be required
for each SPM.
Many of the items listed have been generalised due to the different types
and manufacturers of SPMs.
Except where limited shelf life dictates otherwise, more than 100% back up
may be required when both lead times and usage are taken into account.
9.1 SPARE PARTS
APPLICABLE TO ALL SYSTEMS
Submarine and Floating
spreaders, spool pieces and gaskets 100%
Hoses, both submarine and
Buoyancy tanks or floats 100%
Tanker rail hoses and
first off the buoy hoses 200%
Valves and flanges 20%
Lifting chains, shackles,
Hose lights, battery
packs, etc. 100%
Associated bolts 200%
Pick‑up buoys 200%
Mooring hawsers 200%
Chain support, buoy
shackles, pins, thimbles and lifiks 100%
Triangular plate 100%
Chafing chain 200%
Hawser floats 100%
Messenger lines 200%
Marker buoys 100%
Associated bolts and
Purge fittings 100%
Control system As
Spool pieces 50%
9.2 SPARE PARTS
APPLICABLE TO CALM SYSTEMS ONLY
Buoy Body and Turntable
Chain stoppers 50%
Manhole cover seals 100%
Bogey wheels (for CALMs with bogey wheels only) 50%
Expansion joints 100%
Main bearing seals 100%
Fluid swivel bearing seals 100%
Bearing bolts 100%
Navigational lights complete 100%
Batteries for navigation lights 100%
Associated bolts 200%
Valves and flanges 50%
Anchor Chain System
Shackles and chain links 20%
9.3 SPARE PARTS
APPLICABLE TO SALM SYSTEMS ONLY
Manhole cover seals 100%
Flooding valves 50%
Fender equipment 50%
Navigational lights complete 100%
Batteries for navigation lights 100%
Associated bolts 200%
Chain Swivel 100%
Swivel and Hose Arm Assembly
Main Swivel Seals 100%
Associated bolts 200%
Spool pieces 50%
Section 10. 0
The schedules necessary
for regular maintenance, servicing and replacement of the components of a SPM
can only be established with experience. The condition of individual components
will depend upon specific design parameters, operating history and
environmental factors and will differ for each SPM. A major requirement
therefore is that detailed records are kept of each item of equipment in
service or in spare stock.
10.1 RECORD CONTENT
Records should include:
Basic data of dimensions and
Dates received, dates in
service and reason for retirement.
The exact location of the item of equipment within the system.
Details of wear
observed during inspections.
Details of subsequent
tests, maintenance or repairs.
Such records will be of invaluable assistance and are essential for
ensuring efficient maintenance.
Observations made, and records kept, during the early months
of operating a new SPM are of particular importance as these will give the
first and earliest indication of the deterioration to be expected, particularly
for components which require more frequent replacement. Moreover, these early
observations will enable the terminal operator to revise, if necessary, the
inspection and maintenance schedules outlined in Sections 5 and 6.
Individual components of the SPM should be covered by records
to a degree that will ensure they receive sufficient attention as required by
their function if the system and the degree of wear observed. In this way, the
risk of breakdown and unscheduled repair work will be substantially reduced.
The amount of records kept will depend on the service requirements and design
of the SPM and its operating procedures. Some typical areas which should be
covered are described in Section 10.2 Specimen record sheets are given at the
end of this section and these may prove to be useful for reference purposes.
10.2 TYPICAL AREAS TO BE
COVERED BY THE RECORD SYSTEM
10.2.1 Pre and Post Mooring Checks
Each time a vessel berths at a SPM a general inspection should be made of
all equipment and materials which are within easy reach at that time. Any small
defects should be made good at the earliest opportunity so as to prevent
further deterioration. A check list should be completed by the berthing master
both before and after berthing. A sample of 'Pre and Post Berthing Check
List' is given in Figure 10.1.
10.2.2 Operating Mooring Data
The relevant sections of the 'Operating Mooring
Data' sheet should be filled in every hour a ship is on the mooring, and
if possible every four hours at other times. In weather conditions that are
changing rapidly, the frequency of observations should be increased so that a
re‑construction of the broad pattern can be carried‑ out from the recorded data.
In cases where instruments are not available for recording
certain weather criteria, best estimates should be made and the letter
'E' inserted after the observation to draw attention to the fact that
it was estimated.
The information contained in the data sheets is useful for
relating failures back to specific exceptional conditions. It also enables
operating staff to prepare for similar circumstances in the future. A sample of
an 'Operating Mooring Data Sheet' is given
in Figure 10.2.
10.2.3 Equipment Performance
As stated previously, each item of equipment should be covered
by the record system so that its condition can be monitored and any rapid
deterioration quickly identified. Moreover, inspection and maintenance
schedules can be modified, as necessary, in the light of the experience gained.
Major items for which specimen record or performance sheets
are given are as follows, and samples of record sheets are given in Figures
10.3 to 10.6.
To record the operating
history and performance of mooring ropes based on the number and duration of berthing.
Other mooring assembly components such
as chafing chains, triangular plates, chains and shackles:
Similar to those for mooring hawsers.
To record periodically
the position of the chain stoppers and the angle of pretension on the chain
pendants. These recordings should be made at regular intervals and during any
chain adjustment operation. It is recommended that the measurement of the angle
of pretension should be repeated to reduce errors. The average observation
should be compared with the prescribed angle of pretension. It is recommended
that these measurements be only made during slack tide. (CALM only)
To record the position of
the anchors, the distance between the anchor crown and marker peg is measured.
The records will show whether any drag of the anchors has occurred over a
period of time. Any embedding, scouring, etc., should be noted for each anchor
Submarine and floating hoses:
Specimen sheets for the
Hose Performance Card are given in the OCIMF publication. 'Guidelines for
the Handling, Storage, Inspection and Testing of Hoses in the Field' ‑
10.2.4 Overall SPM Performance
In addition to the records for individual components, records
of berth occupancy, throughput and downtime will, if maintained
over a period of time, give a valuable indication of overall terminal
performance. The required data should be entered every day. Monthly and yearly
cumulative figures expressed as total times and percentages will indicate
performance and utilisation trends. A sample of an 'Overall SPM
Performance Data Sheet' is given in Figure 10.7
SPM RECORD SHEET
BERTH INSPECTION DATA
PRE BERTH CHECK SPM CHECK: POST DEPARTURE CHECX-
TRIM & FREEBOARD
RUBBER EXPANSION PIECES
PRE BERTH CHECK: SPM CHECK: POST DEPARTURE CHECK:
FIGURE 10.1: PRE AND POST BERTHING CHECK