Issued jointly by the

International Chamber of Shipping

Oil Companies International Marine Forum

Society of International Gas Tanker and Terminal Operators Ltd.

First Published 1980 Reprinted 1993

Second Edition 1995 © International Chamber of Shipping, London

Oil Companies International Marine Forum, Bermuda 1980, 1995

ISBN 1 85609 082 5

British Library Cataloguing in Publication Data International Chamber of Shipping Oil Companies International Marine Forum Society of International Gas Tanker and Terminal Operators Ltd.

Ship to Ship Transfer Guide (Liquefied Gases) I. Title 2nd Ed

ISBN 1 85609 082 5

The International Chamber of Shipping (ICS) is a voluntary organisation of national shipowners' associations. Established in 1921, it represents more than half of world merchant tonnage. The interests of ICS cover all aspects of maritime affairs, but it is particularly active in the field of marine safety, ship design and construction, pollution prevention and maritime law. ICS has consultative status with several inter- governmental organisations, including the International Maritime Organization.

The Oil Companies International Marine Forum (OCIMF) is a voluntary association of oil companies having an interest in the shipment and terminalling of crude oil and oil products. OCIMF is organised to represent its membership before, and consult with, the International Maritime Organization and other government bodies on matters relating to the shipment and terminalling of crude oil and oil products, including marine pollution and safety.

The Society of International Gas Tanker and Terminal Operators (SIGTTO) is a non-profit-making association dedicated to the protection and promotion of the interests of its members in the safe operation of liquefied gas tankers and liquefied gas loading and receiving terminals. The Society was founded in 1979 and was granted consultative status at IMO in November 1983. The Society has over 90 companies in membership who own or operate over 80% of world LNG tankers and terminals and 50% of world LPG tankers and terminals.

Notice of Terms of Use

While the advice given in this guide has been developed using the best information currently available, it is intended purely as guidance and to be used at the user's own risk. No responsibility is accepted by the International Chamber of Shipping, the Oil Companies International Marine Forum, the Society of International Gas Tanker and Terminal Operators Ltd, or by any person, firm, corporation or organisation who or which has been in any way concerned with the furnishing of information or data, the compilation, publication, or authorised translation, supply or sale of this guide, for the accuracy of any information or data, for the accuracy of any advice given herein or for any omission herefrom or for any consequences whatsoever resulting directly or indirectly from compliance with or adoption of guidance contained herein even if caused by a failure to exercise reasonable care.

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Foreword

This guide was first published in 1980. It was based on best industry advice and was well received. Since then it has been used by some governments as the basis for national regulations on Ship-to-Ship (STS) transfer operations covering liquefied gas. STS transfer operations have now become routine in many parts of the world and further experience has been built up. Accordingly, in this new edition the guide has been substantially updated to reflect current good operating practice. The layout has also been improved and greater attention has been given to presenting the advice in a more logical manner.

The guide is aimed at providing advice for masters, marine superintendents and others responsible for planning STS transfer operations. It is primarily directed to the transfer of liquefied gas between ocean-going ships. In general, it is aimed at operations taking place at sea (and therefore often beyond normal port services). However, it will also be of relevance in inshore waters or within harbour limits, although in such cases special regard will have to be taken of local regulations. Similarly, the guide does not refer directly to ship movements where one ship may be brought alongside another that is already at a jetty. Such operations, sometimes known as double-banking, should be subject to local regulation and will normally be conducted with the full benefit of all port services. As before, the guide does not deal specifically with transfers between ships and barges or estuarial craft but can be used as guidance for such operations.

The guide does not cover STS transfer operations at offshore production units. Here it can be expected that local regulations will be enforced by terminal operators. However, the guide may be of benefit to operators of such facilities as they formulate their own regulations.

By and large, the guide is limited in its scope to STS transfer operations involving Liquefied Petroleum Gas (LPG) and similar cargoes. The transfer of Liquefied Natural Gas (LNG) cargoes has not yet become commonplace and, as there are some different procedures to be followed, the transfer of such cargoes should only be considered after the additional risks have been addressed.

The guide is not a book of rules. It contains recommendations on safety, minimum equipment levels and good operating practices, but it must always be remembered that more stringent international, national or local regulations must take precedence.

ICS, OC1MF and SIGTTO always welcome suggestions for improvements which can be considered for inclusion in future editions. Comments may be addressed to these organisations at the following addresses:

International Chamber of Shipping Oil Companies International Marine Forum 12 Carthusian Street 15th Floor, 96 Victoria Street London EC1M6EB London SW1E 5JW England England

Society of International Gas Tanker and Terminal Operators Ltd 17 St. Helen's Place London EC3A 6DE England

Table of Contents

CHAPTER Page

FOREWORD III

GLOSSARY VII

CHAPTER 1 GENERAL PRINCIPLES

.1 Preamble 1

.2 Background 1

.3 Scope 1

.4 Parties Involved 1

.5 Control of Operations 2

.6 Safe Watchkeeping 3

.7 Manning for Salient Operations 3

CHAPTER 2 CONDITIONS AND REQUIREMENTS

2.1 Approval from Authorities 5 2.2 Ship Compatibility 5 2.3 Transfer Area 5 2.4 Weather Conditions 6 2.5 Night Berthing and Unberthing Operations 6

CHAPTER 3 SAFETY - GENERAL

3.1 General 7 3.2 Check Lists 7 3.3 Safety During Cargo Transfer 7

CHAPTER 4 COMMUNICATIONS

4.1 General 11 4.2 Language 11 4.3 Voyage Instructions 11 4.4 Initial Radio Contact Between Ships 11 4.5 Navigational Warnings 11 4.6 Communication During Approach, Mooring and Unmooring 12 4.7 Communication During Cargo Transfer Operations 12 4.8 Procedures for Communication Failure 12

CHAPTER 5 OPERATIONAL PREPARATIONS BEFORE MANOEUVRING

5.1 Final Checks on Ship Compatibility 15 5.2 Preparation of Ships 16 5.3 General Safety Requirements 16 5.4 Mooring at Night 16 5.5 Navigational Signals 16

CHAPTER 6 MANOEUVRING AND MOORING

6.1 Basic Berthing Principles 17 6.2 Positioning and Size of Fenders 17 6.3 Mooring Equipment and Preparations 18 6.4 Manoeuvring Alongside with Two Ships Under Power 19 6.5 Manoeuvring Alongside with One Ship Already at Anchor 20 6.6 Nautical Aspects Applicable to Cargo Transfer 20

CHAPTER 7 PROCEDURES ALONGSIDE

7.1 Pre-Transfer Procedures 23 7.2 Tending of Fenders and Mooring Lines 23 7.3 Planning for Cargo Transfer 23 7.4 Transfer of Personnel Between Ships 24 7.5 Hose Connection 24

CHAPTER 8 CARGO TRANSFER OPERATIONS

8.1 Hose Handling 25 8.2 List and Trim 25 8.3 Pre-Transfer Checks 25 8.4 Cargo Flow Rates 25 8.5 Vapour Return 26 8.6 Cargo Transfer - General Requirements 26 8.7 Accidental Cargo Release 26 8.8 Cargo Documentation and Customs Requirements 26 8.9 Operations After Completion of Cargo Transfer 26

CHAPTER 9 UNMOORING

9.1 Unmooring Procedure 29 9.2 Unmooring Checks 29 9.3 Procedure for Unberthing 29

CHAPTER 10 EQUIPMENT

10.1 Fenders 31 10.2 Hoses 33 10.3 Mooring Equipment 34 10.4 Oil Pollution Control Equipment 35 10.5 Gangway 35 10.6 Lighting 35 10.7 Portable Radios 36 10.8 Representative List of Equipment - Two 65,000 dwt Ships 36

CHAPTER 11 EMERGENCIES

11.1 Emergency Signal 37 11.2 State of Readiness for an Emergency 37 11.3 Contingency Planning 37 11.4 Emergency Situations 38 11.5 Safety Drills 38 11.6 Advice on some Emergencies 39 11.7 Transfer Operations with a Ship Aground 40

REFERENCES 41

APPENDIX 1 Operational Safety Check Lists 43

Check List 1 Pre-Fixture Information 44 Check List 2 Before Operations Commence 45 Check List 3 Before Run-in and Mooring 46 Check List 4 Before Cargo Transfer 47 Check List 5 Before Unmooring 48

APPENDIX 2 Part Reproduction of the International Ship/Shore Safety Check List 49

GLOSSARY

Within this guide, the terms below have the following meanings:

AT SEA

The term "at sea" is used loosely throughout this guide. It is intended to indicate off-shore waters or partially sheltered waters. It may be, however, that an STS transfer operation "at sea" is to be conducted within the jurisdiction of a local (port) authority or national government. In such cases reference has to be made to local regulations and it may also be necessary to obtain local approval.

BALLAST

The term "ballast" covers water ballast carried in ships' tanks designated for this purpose.

DEDICATED SHIP

A dedicated ship is a sea-going ship which is permanently fitted with all equipment necessary to carry out STS transfer operations on a regular and long-term (dedicated) basis. A feature of such ships is their ability to move from location to location; accordingly it is common to find such ships able to secure all equipment safely for ocean passages.

DISCHARGING SHIP

A discharging ship is a ship which transfers liquefied gases to another ship.

ESTABLISHED SHIP

An established ship is a ship which has been contracted for a period, usually in a specific location, to act as a mother ship receiving other ships alongside. An established ship is similar to a dedicated ship in that an experienced crew can be expected to be on board. However she can be without permanent means of raising and lowering fenders and accordingly may be alternatively described as a "station tanker".

NON-DEDICATED SHIP

A non-dedicated ship is a sea-going ship which is temporarily equipped to carry out STS transfer operations on a short term (non-dedicated) basis.

ORGANISERS

Organisers are shore-based operators responsible for arranging an STS transfer operation. As described in Section 1.4, the organiser may be a gas trader or an STS agency.

PRIMARY FENDERS

Primary fenders are large fenders used to absorb the impact energy of berthing and wide enough to prevent metal to metal contact between the ships should they roll while alongside one another.

RECEIVING SHIP

A receiving ship is a ship which receives liquefied gases from a discharging ship.

SECONDARY FENDERS

Secondary fenders are fenders used to prevent contact between the two ships, should they be rolling or not parallel to each other. They are especially effective when rigged towards the ends of a ship and are of most benefit during mooring and unmooring operations.

SHIP

Throughout this guide the word ship refers to a liquefied gas carrier.

SHIP TO SHIP (STS) TRANSFER OPERATION

An STS transfer operation is an operation where liquefied gas is transferred between ocean-going ships moored alongside each other. Such operations may take place when one ship is at anchor or when both are either drifting or under power. In general, the expression includes the approach manoeuvre, berthing, mooring, unmooring, hose connecting, hose disconnecting and safe procedures for cargo transfer.

STS AGENCY

An STS agency is an organisation which can provide services for the safe control of STS operations. It can also provide the essential equipment needed such as hoses, fenders and support craft. Generally, such agencies are most commonly used for operations involving non-dedicated ships.

STS SUPERINTENDENT

An STS superintendent is a person specially employed for his expertise to advise on STS transfer operations. Such an expert can be designated to assist a shipmaster in the berthing, mooring and unmooring of ships and to advise during an entire STS transfer operation. STS superintendents are used most commonly during operations involving non-dedicated ships.

TRANSFER AREA

A transfer area is an area within which an STS transfer operation takes place. Transfer areas should be selected in safe zones (see Section 2.3). In coastal areas they will be agreed with nearby coastal authorities and, as appropriate, in accordance with specific port or national regulations.

TRANSFER AT ANCHOR

The expression "transfer at anchor" describes a situation where a cargo transfer of liquefied gas is carried out between ships when they are moored alongside each other and one of the ships is at anchor. It is used as an alternative to either under power or drifting transfer.

UNDERWAY

By definition under the International Regulations for Preventing Collisions at Sea, a ship when underway is not at anchor. However, she may be either steaming or drifting freely with current and weather.

This guide covers ship to ship (STS) transfer operations of liquefied petroleum gases (LPG). Primarily, it is intended to familiarise masters and ship operators with the general principles involved. As found necessary, the advice contained in this publication may be supplemented by instructions from individual shipowners (or ship managers) in order that particular aspects of their own procedures can be covered. Furthermore, in certain port areas it will be found that local regulations apply. These regulations should be followed and where appropriate the recommendations made in these guidelines can be used as additional advice. Other parties may also benefit from studying these guidelines. Such parties can include ship charterers, gas traders and STS agencies, especially those responsible for organising an STS transfer.

The STS transfer of LPG cargoes has become a common practice. Experience gained from these regular operations has proved that STS transfer operations can be safe, given compliance with satisfactory procedures and suitable weather and sea conditions.

This guide is directly concerned with STS transfer operations undertaken "at sea", and therefore in places which may be beyond the assistance of normal port services. As will be seen, the recommendations apply to ocean-going ships when it is intended that they moor alongside each other. However, the guide may also be useful as background when establishing rules for transfer operations between ocean-going ships and barges or estuarial craft in inshore waters. A further use for the guide can be to provide background advice to companies operating offshore storage or production facilities where direct transfer to ocean-going ships takes place.

In addition, the guide may also be of assistance to ships aground and requiring emergency lightening, but in such unique circumstances the procedures adopted may vary from this guidance on a case by case basis.

The guide is limited to the transfer of LPG (butane and propane), ammonia and propylcnc. It excludes products such as ethylcnc and other chemical gases. It also excludes STS transfer operations involving LNG (liquefied natural gas) because of their rarity and the specialised equipment required.

STS transfer operations arc normally initiated by gas traders. They may also be planned where national gas demand has outstripped shore-based storage and in such cases a dedicated ship or an established ship may be used on permanent station as a floating storage facility.

When a gas trader has identified a need, he will normally approach the shipping community for assistance in setting up a safe operation.

His choice will be limited to an operation involving a dedicated ship, an established ship or a non-dedicated ship. In the case of the former he will probably approach a shipowner to set up either a dedicated ship or an established ship arrangement on a time chartered basis and the ship would be equipped accordingly. Where the gas trader's need is only occasional, he will probably opt for an operation involving a non-dedicated ship. Under these circumstances, he would approach the spot market and seek charterparty approval to carry out STS transfer operations. However, to conduct a transfer successfully, the trader will require access to temporary equipment and the necessary expertise. It is in this area that STS agencies come into play. STS agencies usually have stockpiles of the necessary equipment, methods of moving it to the desired transfer area and STS superintendents available to advise locally on an operation with the aim of ensuring a successful outcome. When it comes to the detail of an individual transfer, gas traders often delegate the issuance of voyage instructions concerning STS operations to the STS agency. They may also wish the STS agency to complete pre-fixture information (see Check List 1) on their behalf. Accordingly, in an operation involving a non-dedicated ship, it will be normal to find an STS agency acting as the shore-based organiser.

1.5.1 General

The overall control of an STS transfer operation should be vested in the hands of one individual. This is likely to be one of the masters concerned. In some special circumstances it may be an STS superintendent.

If masters are unfamiliar with, or inexperienced in, STS transfer operations it is recommended that an STS superintendent be employed to advise them. There are specialised STS agencies providing such services on an international basis. It should be noted that for cargo operations of a non- dedicated type it is recommended that an STS superintendent always be used.

7.5.2 Procedures for Navigation

For ship manoeuvres involving a non-dedicated ship, the master taking overall advisory control must be mutually agreed between the two ships and this should be clearly established by both masters prior to the start of operations.

In an STS transfer operation involving an established ship or a dedicated ship, the master of that ship will normally be expected to have the overall advisory control.

For some inshore areas the port authority may require a pilot to be taken. In such circumstances the pilot will be in charge of the navigation and piloting but each master will remain in command of his own ship and should ensure that the check lists contained at the end of these guidelines are followed.

1.5.3 Responsibility for Cargo Operations

Cargo transfer operations should be carried out in accordance with the requirements of the receiving ship.

It is a general recommendation for all cargo transfer operations involving a non-dedicated ship, even those involving coastal ships, that an STS superintendent be employed to advise. In such cases, the STS superintendent should be specially selected for his experience in cargo transfers involving liquefied gas.

1.5.4 Responsibility for Safety

Throughout an STS transfer operation each master remains responsible for the safety of his own ship, its crew, cargo and equipment, and should not permit safety to be prejudiced by the actions of the other master, regulatory officials or others.

STS transfer operations can put additional demands on ships' crews. It has to be remembered that not only are personnel required for cargo transfer operations but also to keep a safe navigational or anchor watch.

Each master should take into consideration the estimated duration of operations to ensure that safe and fatigue-free watchkeeping can be maintained throughout.

For the reasons described in this section, transfer operations taking place simultaneously from both sides of a ship are generally discouraged.

Masters should ensure that sufficient crew members are available for the intended operations. An adequate number of crew will be required from each ship for mooring operations, for hose handling and for derrick or crane control. Due regard should also be taken of Section 8.6 where additional manning for the deck watch is recommended during cargo transfer operations.

Where an STS transfer operation is to be arranged within national waters, it will be necessary for the organisers to check local regulations and to gain local approval. This may require the organiser and shore authority to agree the transfer area to be used and to take into account other requirements. Matters pertaining to contingency plans should also be addressed at this stage (see Section 11.3).

When an STS transfer operation is about to begin, the organiser should notify the local authorities and the government agencies concerned. This may be done either directly by the organisers or, once local requirements are known, by formally delegating the task to the master of the ship in overall charge.

When organisers are planning an STS transfer operation they should ensure that the ships to be used are compatible in design and equipment and that mooring operations, hose handling and communications can be conducted safely and efficiently. The initial information to be agreed by the organiser, based on feedback from the two shipowners, and usually prior to charter, is given in Check List 1.

Transfer areas may be relatively large or quite small: the space available will dictate the type of manoeuvre. In the case of manoeuvres at sea, where it is intended that both ships are underway, a large transfer area will be needed to accommodate the necessary manoeuvres. A ship approaching another ship at anchor will of course require a much smaller overall area. Sometimes this can be within port limits.

There should be prior agreement between the two masters about the location of the transfer area and the methods of mooring (and anchoring, if to be used).

Points to be considered by organisers when selecting the transfer area are:

(a) The destinations of the ships concerned to avoid unnecessary deviation. (b) The need to notify and obtain agreement of a coastal authority. (c) The shelter provided from the weather, particularly from sea and swell. (d) Present and forecast weather conditions. (e) Tidal current conditions. (f) Safe distances from off-shore installations. (g) The availability of a safe zone free from small craft. (h) The need for sea-room and water-depth to be sufficient for manoeuvring during berthing and

unberthing. (i) Sufficient sea-room should be available to allow for normal drift or steaming distances when

cargo transfer operations are to be conducted underway, (j) Where cargo operations are to be undertaken at anchor, the transfer area should allow a safe

anchorage, and the nature of the sea-bed should be taken into account, (k) The traffic density.

The preceding points should also be borne in mind by masters and STS superintendents if it becomes necessary to change the position of the transfer area due to bad weather.

It is impracticable to lay down limiting weather conditions under which STS transfer operations can be carried out because much will depend on the effect of the sea and swell on the fenders and the relative rolling movement produced in the participating ships, taking into account their relative freeboards.

If cargo transfer is to take place at anchor the combined effect of current and weather conditions on the yawing movements of the anchored ship and the ultimate strain on its anchor cable should be considered.

All available weather forecasts for the area should be obtained before and during operations.

Throughout any berthing operation the visibility should be good enough for safe manoeuvring, taking into account safe navigation and collision avoidance requirements. Manoeuvres should only start when both masters (and the STS superintendent) are satisfied that conditions are suitable for mooring and cargo transfer.

Berthing and unberthing operations should be conducted during daylight unless the masters concerned are experienced in STS manoeuvring operations.

For all STS transfer operations each master remains responsible for the safety of his own ship, its crew, cargo and equipment, and should not permit safety to be prejudiced by the actions of others. Each master should ensure that the procedures recommended by this guide are followed and, in addition, that internationally accepted safety standards are maintained. In this regard, the three most prominent international safety manuals in use for cargo handling advice are (a) the International Safety Guide for Oil Tankers and Terminals, (b) the Tanker Safety Guide (Liquefied Gas) and (c) Liquefied Gas Handling Principles on Ships and in Terminals.

The overall safety of any STS transfer operation depends on the type and condition of the equipment in use and strict adherence to well documented safety procedures.

Check lists (presented in chronological order) for STS transfer operations will be found in the appendices to this guide. These should assist organisers and masters to adhere to relevant safety procedures. The check lists should be used not only at the time of transfer, but also when organisers are planning an operation (refer to Check List 1). Adherence to check list procedures will ensure that the most essential aspects of an operation are covered.

The basic industry related safety requirements for a transfer operation are similar to those for a normal port cargo operation as contained in the International Safety Guide for Oil Tankers and Terminals (ISGOTT), particularly Appendix A (Parts A and C). For convenience, the relevant check list from that guide will be found in Appendix 2. However the following points are emphasised for an STS transfer operation:

3.3.1 Smoking and Naked Lights

Regulations regarding smoking and the use of naked lights should be strictly enforced. Warning notices should be displayed and smoking rooms should be designated and clearly marked.

3.3.2 Earths on Electrical Switchboards

Earth indicator lights showing on the main switchboard indicate a faulty circuit; such faults should be immediately traced and isolated. This is to avoid the risk of arcing - especially in deck areas where hazardous accumulations of gas may be present.

3.3.3 Boilers and Diesel Engines

On steamships, in order to avoid hot ash falling onto a ship's decks during cargo transfer, soot- blowing of boilers should be carried out before commencing the approach manoeuvre.

The combustion characteristics of diesel engines should be closely monitored.

In case of sparking from the funnel, transfer operations must be stopped immediately.

3.3.4 Ship to Ship Electrical Currents

3.3.4.1 The Elimination of Electrical Current and Electrostatic Charge in Cargo Hoses

In order to eliminate the potential for incendive arcing between the two ships when presenting the hose string for connection, either:

(a) A single insulating flange should be fitted within each hose string (or at one ship's manifold), or (b) One length of electrically discontinuous hose should be fitted in each hose string.

The reasons for this precaution are as follows. A ship's hull may obtain a significantly different electrical potential relative to the surrounding sea. This usually depends on the amount of cathodic protection being applied to the external hull, and on ships such cathodic protection can be provided by an impressed current system. These systems are automatically controlled and when functioning correctly, will maintain a hull at an electrical potential of between 0.15 and 0.2 volts relative to built- in reference cells. If both ships' systems are working correctly, within the above range, potential differences between the ships will be insignificant. If, however, there is an imbalance between the two ships' systems, or if one system is inoperative or the other overworking, then the ship to ship potential difference could be as much as 0.4 volts. Such a difference could give rise to incendive arcing if an intermittent low resistance path is made. Electrically continuous cargo hose provides such a path. Therefore, on cargo hose connection or disconnection, unless precautions are taken, arcing could take place between the hose and manifold flanges. This risk is addressed by fitting a single insulating flange, or one length of electrically discontinuous hose, as mentioned above.

To prevent localised accumulation of electrostatic charge in a hose, the hose string should be electrically continuous to both ships on either side of the point of insulation. This means that when an insulating flange is used at a ship's manifold, it is essential that it only be used on one ship. To do otherwise would leave an insulated hose length between the two ships upon which an electrostatic charge could accumulate. (It is also important that, apart from the advice above regarding the need for one length of electrically discontinuous hose, only electrically continuous hose be used throughout each hose string.)

3.3.4.2Other Places where Electrical Arcing may Occur

The probability of each ship having a different electrical potential gives rise to the possibility of electrical currents (and arcing) not only at the cargo manifold but also at other points. This section indicates the other areas at risk.

All ship to ship mooring lines should be insulated either by using the natural properties of soft mooring lines such as nylon, or by attaching a soft rope tail of nylon (or similar material) to the eye of each steel wire mooring line. Soft rope tails should have a similar safe working load (SWL) to the wires on which they are fitted. They should also be of suitable length so that they extend to the outboard side of the ship receiving the mooring.

Care should also be taken to avoid low resistance ship to ship electrical contact in the following areas:

(a) Non-insulated metallic ladders or gangways between the ships - by the fitting of rubber ends. (b) Derrick or crane wire runners and hooks - by careful operation. (c) Unprotected bare wires and chains within fender support nets or cages - by good quality

maintenance.

3.3.5 The use of Radio and Satellite Communication Equipment

Transmissions from a ship's main radio station can cause electrical resonance in insulated parts of some ship fittings such as mast-stays and this can cause arcing across deck fittings. Similar arcing can occur on ship's radio aerials, especially over the surface of insulators when they have a coating of salt, dirt or water.

Therefore, the use of a ship's main radio equipment during cargo operations can be dangerous and transmission should not be permitted during periods when there is the possibility of flammable gas in the region of the aerials or where there is doubt about the effective earthing of stays, derrick equipment and other such fittings.

Accordingly, the main radio transmitting aerials on both ships should be earthed (grounded) and neither ship should use this equipment whilst alongside one another. When available, satellite communications equipment can be used for communications; however, the risks described below should be taken into account.

Satellite communications equipment normally operates at 1.6 GHz and the power levels generated are considered to present few ignition hazards. However, this equipment should not be used when flammable gas is in the vicinity of antennae.

VHP and UHF communications are of low energy and therefore do not produce the same potential dangers as might be expected from a ship's main radio station. Accordingly, such equipment can be used for communication even while ships are together and may also be an alternative to the main radio when within range of a suitable coast station.

The hand-held VHP and UHF radios, as used for mooring and cargo operations, should be of intrinsically safe manufacture.

3.3.6 The Use of Radar

3.3.6.1 General

The use of radar involves the operation of electrical equipment which is not intrinsically safe. Furthermore, and depending on the relative size of the two ships, the radar beam of one ship may at times sweep the cargo deck of the other during cargo transfer operations, and be close enough to create potentially hazardous power densities in areas where flammable gas mixtures could be present. Therefore, consultation between masters is advisable before a radar is used during cargo transfer operations.

3.3.6.2The Use of 3 cm and 10 cm Radars

Radiation from radars operating at frequencies above 9000 MHz (3 cm) may be considered safe at distances of over 10 metres. Accordingly, the radiated power from such radars should not present an ignition hazard provided scanners are correctly sited above the superstructure. Thus, radars operating in the 3 cm waveband will normally be safe but should only be used with discretion.

At the lower frequencies, as used by 10 cm radars, the possibility of induced arcing in parts of a ship's structure is present at ranges up to 50 metres. As a consequence, 10 cm radars should not be used when there is a possibility that a scanner may point directly at or near the cargo deck of the other ship.

3.3.7 Gas Accumulation

An STS transfer operation should be suspended if there is risk from cargo vapours around the decks, manifold or vents of either ship. It should not be resumed until the cargo leak has been identified and stopped, and all gas has dispersed.

The operation of slip-tube apparatus for measuring tank levels on pressurised ships can produce gas evolution on deck but, if operated safely, this practice is normally acceptable.

3.3.8 Electrical Storms

When an electrical storm is present or expected in the transfer area, a cargo transfer operation should be suspended.

3.3.9 Galley Stoves

Oil or gas fired galley stoves must be extinguished during cargo transfer operations.

3.3.10 Readiness of Fire Fighting Equipment

Fire fighting equipment should be ready for immediate use on both ships. Dry powder monitors on each ship should be pointed towards the cargo manifold in use and left in a suitable condition for hands-off operation.

3.3.11 Accommodation Openings

All access doors to the accommodation should remain closed during cargo transfer operations. The master of each ship should designate those access doors that will be used for personnel transit. All doors opened for personnel transit should be closed immediately after use.

The air conditioning system for the accommodation should be switched to the recirculation mode.

3.3.12 Safety Zone Round the Ships

During cargo transfer operations no craft should be allowed alongside either ship or within a pre- agreed exclusion zone set at a safe distance. It would be normal to exclude such craft from within a 500 metre range. In national waters such restrictions should be possible under port authority approval. For operations further off-shore, where jurisdiction is less clear, the subject should be addressed in Navigational Warnings (see Section 4.5) and by proper selection of the transfer area (see Section 2.3).

Good communications between the ships is an essential requirement for successful STS transfer operations. The principal recommendations on this subject are addressed below.

To avoid any misunderstanding, a common language for communication should be agreed before operations commence. In this connection, attention is drawn to the Standard Marine Communication Phrase, using the English language, published by the International Maritime Organization (IMO).

•i^Hi^B^M^H^H^^MHI

4.3.1 Non-Dedicated Ships

For operations involving a non-dedicated ship, it is usual for an STS agency to be contracted by gas traders to supply the necessary additional equipment and expertise. Normally such agencies send advance voyage instructions to the ships concerned. A typical message is appended to this chapter (see Annex 4.1).

4.3.2 Established Ships and Dedicated Ships

For those operations where either an established ship or a dedicated ship is involved it would be normal for the other ship to expect advance advice on the operation, as if arriving at a normal port.

The ships should establish initial contact by satellite communications or radio as early as practicable to plan operations and to agree to the transfer area.

If the transfer area is outside the jurisdiction of a coastal authority, the master having overall advisory control (see Section 1.5.2) should broadcast a navigational warning to all ships advising:

Name and nationality of the ships involved. Geographical position of operations. Time of starting operations. Nature of operations. Expected duration. Request for wide berth.

On completion of the transfer, the master having overall advisory control should cancel the navigational warning.

As the ships come into the transfer area, contact should be established on VHP Channel 16 or 72 at the earliest opportunity, thereafter switching to a mutually agreed working channel. Approach and mooring should not be attempted until good VHP communication has been confirmed between the two ships. At this time, in accordance with the information exchanged, Check Lists 2 and 3 should be satisfactorily completed. The same VHP communication must be confirmed before unmooring, at which time Check List 5 should be satisfactorily completed.

Ships' officers responsible for mooring stations should be provided with hand-held radios.

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At all times during cargo operations, essential personnel of both ships should have reliable means of communication with them, such as hand-held radios.

Additionally, as covered in Section 8.6, visual contact between responsible officers on both ships is recommended during critical periods of the cargo transfer.

If communication breakdown occurs during an approach manoeuvre, the manoeuvre should be aborted and subsequent actions taken by each ship should be indicated by the appropriate sound signals as prescribed in the International Regulations for Preventing Collisions at Sea.

During cargo operations, in the event of a breakdown of communications on either ship, the emergency signal (see Section 11.1) should be sounded and all operations in progress should be suspended immediately.

In general, operations should not be resumed until satisfactory communications have been re-established.

5.1.1 Communications

Satisfactory communications between the ships should be confirmed by checking:

(a) That both ships are fitted with operational VHP. (b) The VHP frequencies (channels) to be used. (c) Whether it is possible to communicate readily in English; if not, the alternative common

language that is to be used (see also Section 4.2).

If the above checks find a serious communication problem or lack of understanding of the operation among either of the crews, then action should be taken to solve this issue by, for example, transferring an experienced person from one ship to the other, before operations begin.

5.1.2 Mooring Checks

The ships should exchange the following information:

(a) The length overall and parallel body length of the ship. (b) The distance from the cargo manifold centre to the stern. (c) Whether the ship's side to be used for mooring the other ship is free of obstructions. (d) The number of enclosed fairleads and mooring bitts and their distance from the bow and the

stern on the side of the ship used for berthing. In this respect the master having overall advisory control should prepare a sketch of the proposed mooring layout with distances marked thereon.

(e) The maximum expected freeboard differential between the two ships.

The information requested in (e) above is important for determining the efficiency of mooring lines. Pxperience suggests that a problem is likely if the freeboard difference exceeds 10 metres. Beyond this distance the vertical orientation of mooring lines is increased such that their efficiency is seriously affected.

5.7.3 Cargo Hose Checks

The ship supplying the cargo hose should determine from the other ship:

(a) The diameter and class (ANSI (ASA), DIN etc.) of cargo manifold flange to be used. (b) The anticipated minimum and maximum height of the cargo manifold from the waterline

during the transfer operation. (This is so that the correct hose length can be determined.) (c) The suitability of the hose for the properties of the cargo, including temperature and pressure. (d) Whether the cargo cranes or derricks are in a satisfactory condition and of suitable safe working

load (SWL) to handle cargo hose. (e) The adequacy of hose supports, at the ship's side, to ensure that hoses do not chafe and that

they are not bent beyond their minimum allowable bending radius.

The following preparations should be made by the masters of both ships before manoeuvres begin:

(a) A study of the procedures given in this guide, supplemented by any instructions issued by shipowners.

(b) Appropriate checks, such as the testing of essential cargo equipment. Procedures of this type are described in the Tanker Safety Guide (Liquefied Gas) - see Reference 2.

(c) Crews fully briefed in procedures and hazards, with particular reference to mooring and unmooring.

(d) Checks made to ensure that each ship will be able to comply with all requirements of the Operational Safety Check Lists (see Appendices).

(e) Engine controls, steering gear and all navigation and communications equipment confirmed to be in working order.

(f) Ship upright (having no list) and at a suitable trim. (g) Cargo manifolds and hose handling gear prepared. (h) Area weather forecasts for the transfer period obtained, (i) Fenders and mooring equipment checked.

5.3./ Check Lists

Check lists are essential reminders of the principal safety factors to be considered. They should be supplemented by continuous vigilance throughout the whole operation. Operational Safety Check Lists to be used during the various stages of the operation are given in the Appendices.

Before mooring operations commence, each ship should confirm with the other that all items on Check Lists 2 and 3 have been checked and found correct.

5.3.2 Action in Case of Infringement of Safety

If either ship fails to observe any of the safety requirements at any time during the STS transfer operation, this should be brought to the attention of the master of the ship concerned and operations suspended until the situation is rectified.

Mooring during the hours of darkness should only be undertaken by experienced masters or with the assistance of an STS superintendent.

It is necessary that adequate lighting is available in the area of the fenders and around the ships' sides (see also Section 6.4.1).

The navigation lights and shapes to be shown, and the sound signals made, during STS transfer operations are those required by the International Regulations for Preventing Collisions at Sea, and local port regulations.

From the start of the approach manoeuvre, each ship should display the appropriate visual signals and should keep them displayed until the operation is completed and the ships have separated.

6.1.1 Manoeuvres with Two Ships Under Power

Experience has shown that a successful manoeuvre to achieve a satisfactory berthing operation can be carried out with both ships making way and, in general, this is the preferred manoeuvre for open waters. One ship (the constant-heading ship), normally the larger, maintains steerage way at slow speed on a constant heading, usually with wind and sea from right ahead (as requested by the manoeuvring ship). The smaller ship (the manoeuvring ship) then manoeuvres alongside.

It is recommended that the manoeuvring ship approaches and berths with her port side to the starboard side of the constant-heading ship.

It is customary to use mooring lines from the manoeuvring ship but it may be necessary to supplement these with lines from the constant-heading ship.

6.1.2 Manoeuvres with One Ship at Anchor

In fine weather conditions, equally successful berthing operations can be undertaken while one ship is already at anchor. This manoeuvre can be preferred for more constrained transfer areas, especially when tug assistance is available. It is not a difficult operation given a positive current and a steady wind from the same direction. Where current and wind are not from the same direction or the wind varies in speed or direction the anchored ship can yaw (or lie cross-current), making it difficult for the manoeuvring ship to berth alongside. In these circumstances tug assistance may be advisable to hold the anchored ship on a steady heading during berthing. (Tug assistance for the manoeuvring ship is also used at some in-port transfer areas.) Berthing should not be attempted when the tidal stream is due to change.

When approaching a ship at anchor some masters recommend a wider angle of approach than that adopted for manoeuvres underway. A wider angle of approach, especially when tugs are not available, helps to avoid early ship to ship contact in cases where the anchored ship might yaw unexpectedly. It is usually recommended that the manoeuvring ship approaches and berths with her port side to the starboard side of the other ship. However, mooring alongside a ship at anchor may be performed on either side with the aid of tugs and a pilot.

It is customary to use mooring lines from the manoeuvring ship but it may be necessary to supplement these with lines from the ship at anchor.

6.2.7 Fender Positioning

For dedicated ships, it is probable that they will be fitted with permanent fenders operated by winches and davits. These fenders will be positioned at pre-assigned locations along the hull.

For established ships, fendering operations will be carried out in accordance with local practice.

For non-dedicated ships, it is probable that fendering operations will be carried out with the assistance of an STS agency. Such companies usually have service craft available and these tugs will normally tow the fenders into position. The fender string may be made up to a pre-arranged length to suit each ship's parallel body. Alternatively, individual fenders will need to be positioned alongside with their towing pennants (see Section 10.1.4).

Fenders can be secured in place on either ship. However, it is normally preferable that fenders be secured to the manoeuvring ship (as it is usually the smaller ship). By this means, the number of fenders can be minimised by positioning them to cover the actual areas of ship to ship impact irrespective of where it may occur. For some operations involving established ships, fendering of the established ship is commonly practised as an alternative. This requires care in design and greater care during manoeuvring.

When fenders are fitted to the manoeuvring ship, primary fenders should be positioned one at each end of her parallel body, with similar additional units fitted in between (see Section 10.1). In some operations, where four fenders are used it has been found beneficial to position them in two groups of two. In this way, and with each group positioned well forward or well aft on the parallel body, better protection can be provided in case one fender bursts on impact. If necessary, secondary fenders may be positioned fore and aft of the parallel body where ship to ship contact may occur particularly during mooring or unmooring when ships may not be lying parallel to each other.

To minimise the possibility of fenders riding onto the deck of either ship, primary fenders should be floating throughout the operation (see Section 10.1). On the other hand, due to the shape of a ship's hull at the ends of the ship, secondary fenders are often hauled up into position close to main-deck level.

6.2.2 Size of Fenders

Apart from other considerations, fender size will also be dictated by the freeboard of the ships. Fenders that are too big may ride up and roll onto the deck due to ship motion. The diameter of each floating fender should be no more than half the minimum freeboard of the smaller ship.

The importance of good quality mooring lines, efficient winches and deck machinery should be recognised. This is especially true on board the manoeuvring ship whose mooring lines will be used most commonly. However, it should also be addressed on the constant-heading ship where rope-messengers have to be made ready between fairleads and deck winches. Mooring operations should be managed to ensure expeditious mooring line handling. Moorings should be arranged and rigged to allow safe and effective line tending when the ships are secured together.

The mooring plan adopted will depend upon the size of each ship and the difference between their sizes. As a general guide the diagram below illustrates a recommended and proven mooring-plan for an STS transfer operation in off shore waters (see also Section 10.3).

It is important when agreeing a mooring plan to ensure the following:

(a) Mooring lines are of sufficient length to avoid overstressing during freeboard changes. (b) Mooring lines are not too long so allowing unacceptable movement between ships. (c) Mooring lines leading in the same direction are of similar material. (d) Mooring lines are not likely to escape from open fairleads.

6.4.1 General Advice for Controlling the Two Ships

Each ship should take the following into account:

(a) Engine controls, steering gear and all navigation and communications equipment should be in working order.

(b) A proficient helmsman should be assigned to steer each ship. (c) Small changes of course, as requested by the manoeuvring ship, should be followed by the

constant-heading ship. (d) Ship's speed should be controlled by adjusting engine revolutions (or propeller pitch) rather

than using the relatively coarse engine room telegraph system. Engine speed adjustments on the constant-heading ship should only be made at the request of the manoeuvring ship. Any adjustment should be limited: for example, to plus or minus 5 rpm.

(e) At night the deck should be adequately lit and, if possible, the ship's side and fenders should be spot lighted.

(f) The side for mooring should be clear of all over-side obstructions, permanent or otherwise. (g) The navigation lights and shapes referred to in Section 5.5 should be displayed. (h) There should be radio (or telephone) contact between the bridge and mooring gangs, (i) There should be effective VHP communications between the masters of each ship.

6.4.2 Detailed Advice for Manoeuvring Alongside

Although individual masters will have their own preference for the method of manoeuvring their ship, the following points are emphasised for STS transfer operations:

(a) The masters of both ships should always be prepared to abort a berthing operation if necessary. The decision should be taken in ample time while the situation is still under control. The masters of both ships should be immediately informed of each other's actions. The sound signals specified in the International Regulations for Preventing Collisions at Sea must be complied with.

(b) At all times each ship is responsible for keeping its own lookout. (c) Throughout manoeuvring the wind and sea should be ahead or nearly ahead. (d) The angle of approach adopted by the manoeuvring ship should not be excessive. (e) Experience has shown that the best method of berthing is for the manoeuvring ship to approach

the constant-heading ship from broad on the quarter on the side of berthing. On closer approach she should parallel the course of the constant-heading ship, about 50 to 100 metres off. The manoeuvring ship should then position her cargo manifold in line with that of the constant-heading ship. Contact is then made by the manoeuvring ship reducing the distance by appropriate rudder movements until fenders touch.

(f) The two ships should make parallel contact at the same speed with no astern engine movements being necessary.

(g) The effects of ship interaction should be anticipated when manoeuvring at close quarters. Hydrodynamic interaction between ships varies, and knowledge of pressure fields around two ships moving through the water is important. For example, the forward motion of the two ships driving the sea between them can push the bows of the ships apart and it is therefore important to secure the forward breastlines and headlines as soon as possible.

(h) It is normal for all mooring lines to be deployed from the manoeuvring ship and for the eyes of these lines to be put on the mooring bitts on the constant-heading ship - but see (i) below.

(i) Consideration should be given to unmooring procedures when the mooring plan is agreed. It is usually recommended that the final mooring lines to be let go (when unmooring) be turned-up in a figure-of-eight on mooring bitts on the constant-heading ship.

(j) If it is intended to use a line throwing gun, the foredeck of the other ship should be cleared of any aerials or similar overhead obstructions. A warning should be given by loud hailer before firing, at which time all personnel on the other ship should be abaft the cargo manifold.

(k) Strong rope messengers should be readied on the constant-heading ship and, in addition, rope stoppers should be shackled in way of each mooring bitt. Weighted heaving lines should be ready for immediate use and, as appropriate, they should be pre-connected to mooring lines.

(1) When mooring at night, all unnecessary lights should be switched off and visual lookouts supplemented by a continuous radar watch on one ship. (Caution: see Section 3.3.6.)

6.4.3 Manoeuvring a Combined Two-Ship System to Anchor

On completion of mooring, the constant-heading ship will power all future manoeuvres and, if a transfer at anchor is planned, proceed to the agreed anchoring position which should be right ahead and at close distance. During this time, the manoeuvring ship will have its engines stopped and rudder amidships or angled towards the constant-heading ship. It should be emphasised that, in order to avoid severe problems for the manoeuvring ship, which can be created by stern wash from the propeller, the constant-heading ship should not use strong astern engine movements. In fact, at the slow speed under which the berthing manoeuvre is carried out, the ships will tend to lose speed rapidly without the need for strong astern movements.

The constant-heading ship should use the anchor on the side opposite that on which the other ship is moored.

A summary of anchoring procedures may therefore be given as follows:

(a) From the time the manoeuvring ship is secured alongside to the time the constant-heading ship is anchored, the latter assumes responsibility for the navigation of the combined "two-ship" system.

(b) The manoeuvring ship should be informed of any engine and rudder movements made by the constant-heading ship as she manoeuvres to anchor.

(c) Once at anchor, each ship is responsible for keeping its own anchor watch.

STS transfer operations involving one ship already positioned at anchor are encountered quite frequently. For such operations, one ship anchors in a predetermined position using the anchor on the side opposite that on which the other ship will moor. A berthing operation should only be carried out after the anchoring ship is brought up to her anchor and is lying on a steady heading with reference to prevailing current and wind conditions. When this is achieved, the master of the anchored ship should advise the other master.

The type of berthing operation then undertaken by the manoeuvring ship is similar to a normal approach to a jetty. However, a careful watch should be kept on the heading of the anchored ship and the manoeuvring ship should be advised immediately by the anchored ship if she has any tendency to yaw. Where there is a tendency to yaw excessively, a tug should be employed to hold the anchored ship on a steady heading or the operation postponed (see also Section 6.1.2).

The two principal methods of berthing and mooring have been described above in Sections 6.4 and 6.5. Each method suggests that, for cargo transfer, a transfer at anchor is the preferred solution. However, when ships are manoeuvred together under power (Section 6.4), suitable alternatives to anchoring are (a) transfer while making way and (b) drifting transfer, described in Sections 6.6.2 and 6.6.3 respectively. For these operations reference should also be made to Section 5.5 regarding navigation lights and shapes.

6.6.1 Transfer at Anchor

The nautical aspects of bringing a combined two-ship system to anchor have been covered in Sections 2.3, 3.3.6, 3.3.12 and 6.4.3. These procedures attend to the principal nautical aspects needing to be covered for transfers at anchor.

However, attention is again drawn to earlier comments on the need for safe watchkeeping, including anchor and deck watches on both ships.

6.6.2 Transfer While Making Way

Local conditions, such as those where water depths are too great for anchoring, sometimes demand that cargo transfer be carried out with the two-ship system under power and making way through the water. As long as adequate sea room is available, traffic conditions are suitable, weather and sea conditions and forecasts are satisfactory, then transfers while making way can be carried out, but suitable large diameter fenders should be used.

Under such circumstances, while the ships are moored together as a unit, safe navigation and collision avoidance is usually the responsibility of the constant-heading ship (see Section 6.4.3). Transfer while making way requires a full navigational watch to be maintained on the bridge of each ship.

When mooring has been completed and the heaving movements of the fenders are acceptable to both masters, hose connecting and cargo operations may commence in the manner indicated in Chapters 7 and 8.

For transfers while making way, after completion of mooring (as described in Sections 6.4.1. and 6.4.2) the constant-heading ship, rather than anchoring, maintains steerage way at slow speed on a steady course and the manoeuvring ship keeps its rudder amidships and remains (with engines stopped) as a towed ship. If it is necessary to minimize towing loads on the moorings, the constant- heading ship should alter her engine revolutions sparingly, adjusting speed very gradually. The chosen course and speed should be agreed by the two masters and should result in minimum relative movement between the two ships and minimum turbulence in the gap between the hulls.

Throughout the cargo transfer, close attention should be paid to mooring lines and fenders to avoid chafing and undue stress, particularly that caused by towing loads. If at any time mooring lines need to be re-positioned or adjusted, bearing in mind that the ships are under power, this should only be done under very strictly controlled conditions.

6.6.3 Drifting Transfer

As an alternative to transfer at anchor and provided conditions are satisfactory and a transfer area of suitable size is available, it can be advantageous to carry out cargo transfer while the two ships are allowed to drift freely under the effects of the weather.

If deteriorating weather conditions are likely to cause the ships to roll unacceptably, by careful use of engine movements, the ships should be brought to a heading which results in minimum movement.

Constant attention should be paid to mooring lines and fenders to avoid chafing and undue stress, particularly that caused by changes in relative freeboard. If at any time mooring lines need to be re- positioned or adjusted, this should only be done under strictly controlled conditions.

Once the two ships are securely moored, the masters of both ships should ensure that Check List 4 has been satisfactorily completed and that a safe condition has been established.

Attention is drawn to Chapter 3 where some basic safety precautions required during cargo transfer have been outlined. Attention is also drawn to Chapter 11 where vital precautions are outlined covering emergencies. In particular, both ships should have their main engines ready for immediate use and be ready to disconnect hoses at short notice.

The planning of a cargo transfer operation should include information on the following:

(a) Quantity of each grade of cargo. (b) Sequence of grades. (c) Cargo density, temperature and pressure. (d) Cargo tank minimum design temperatures. (e) Line cooling. (f) Cargo heating requirements. (g) Initial transfer rate. (h) Maximum transfer rate. (i) Procedures for the use of a booster pump. (j) Agreed procedures if blending or mixing is to be employed. (k) Maximum Allowable Relief Valve Setting (MARVS) including port and sea settings. (1) Procedures agreed for vapour control or vapour return. (m) Signal for slowing down transfer. (n) Signal for stopping transfer. (o) Emergency stop signal. (p) Emergency Shut-Down (ESD) arrangements. (q) Manifold valve closing period. (r) Contingency plans for emergencies such as leakage or spillage. (s) Ballasting and deballasting.

Procedures for heating cargo, if transferring from refrigerated to pressurised storage, should also be taken into account.

Throughout cargo transfer, fenders should be in the agreed positions and mooring lines should be watched for excessive loads. In addition, power for the mooring winches should always be available on both ships.

Experience has shown that it is sometimes necessary for essential personnel to move between ships. If this is strictly necessary, safe means of access should be provided for their use (see also Section 10.5).

7.5.7 Manpower for Hose Connection

Dedicated ships may be fitted with specialised hose handling equipment.

For operations involving either an established ship or a non-dedicated ship, the two ships connecting the hoses will be expected to provide suitable personnel.

7.5.2 The Care of Insulating Flange During Hose Connection

During hose connection and disconnection, an insulating flange fitted in a hose (see Section 3.3.4.1) must not be allowed to touch any part of the ship's decks or other structures. Such contact would short circuit the flange, so defeating its purpose, and allow the possibility of electrical arcing at the cargo manifold.

Hose strings should be of sufficient length to avoid over-stressing and chafing throughout the cargo transfer. To establish the correct hose length, changes in relative freeboard and ship movement must be taken into account. Only hoses in good condition and suitable for the cargo to be transferred should be used and hose strings, when made up, should be tested. Further details of six-monthly test procedures for individual hose lengths are given in BS 4089, see References and Section 10.2.

Throughout cargo transfer, hose strings should be properly suspended by derricks or cranes of both ships. This will avoid chafing and kinking.

For guidance, a rule of thumb for calculating the minimum bending radius (MBR) of a rubber hose is:

MBR = Nominal Bore of Hose x 4

(For example, a hose of 12 inches nominal bore will give a minimum bending radius of approximately 48 inches).

During cargo transfer, ballast operations should be performed in order to avoid excessive changes in freeboard and excessive trim by the stern. Listing of either ship should be avoided, except as required for cargo tank draining on the discharging ship.

Before cargo transfer commences, good communications should be established between essential personnel on each ship and the pre-transfer checks (see Check List 4) should be satisfactorily completed. In addition, attention should be given to the appropriate checks from ISGOTT (see Appendix 2).

Before starting cargo transfer, the discharging ship must be informed by the receiving ship of the flow rates required for the different phases of the cargo operation. If variations in transfer rate become necessary, the receiving ship should advise the discharging ship accordingly.

During cargo transfer, the maximum transfer rate should be kept consistent with the receiving ship's reliquefaction capacity. Alternatively a vapour return hose connection should be made between the ships.

As with other cargo transfer operations there are safety advantages in providing a vapour return connection between ships. It it can limit the need for vapour release to atmosphere. It can act as a safety release or can be used to limit the need for reliquefaction. Furthermore, it may improve the transfer rate. However, while recommended, a vapour return connection is not essential for STS transfer operations

Throughout cargo transfer operations, the discharging ship and the receiving ship should station a responsible person at each cargo manifold to observe the hoses and to check for leaks. In addition, on the discharging ship, throughout the cargo transfer, a responsible person equipped with a portable radio should be stationed at or near the cargo pump controls to take action as required.

Cargo transfer should begin at a slow rate to enable the receiving ship to check that the cargo pipeline system is correctly set. A slow rate may also be required to ensure a gradual cool-down of the receiving ship's tanks. The transfer rate should also be reduced when the receiving ship's tanks are reaching their filling limits.

Towards the end of transfer and at other critical periods, visual contact should be established between responsible officers on both ships. This should be in addition to portable radio communication.

Shipowners should advise their masters of Customs documentation requirements. It is normal for the quantity transferred to be agreed between both masters in accordance with individual shipowners' instructions.

The agreed transfer rate should not exceed the following recommended flow rates for cargo hose:

Any leakage or spillage should be reported immediately to the officer in charge who should stop the cargotransfer.

After completion of cargo transfer the following operations should be carried out:

(a) All hoses purged into one or other ship prior to disconnecting. This entails suitable purge connections to be fitted and one such arrangement is depicted in figure 2.

(b) Hoses disconnected, taking precautions to ensure that no liquid is left in the cargo transfer system. The pressure in the system should be released through a bleed valve or through the drain line into the vapour return line.

(c) Cargo manifolds and cargo hoses securely blanked. (d) Authorities informed of completion of cargo transfer and the anticipated time of unmooring.

FIGURE 2: HOSE PURGING ARRANGEMENTS

The hose purging procedure made possible by the above arrangement is as follows:

1. Drain the hose of liquid 2. The discharging ship to blow hot vapour through the hose 3. The discharging ship to purge the hose with nitrogen 4. Close the two ship's manifold valves and the hose-end valve 5. Purge the hose-end spool piece with nitrogen through the connections provided.

9.1.1 Unmooring While One Ship is at Anchor

Where STS transfer operations have taken place at anchor, under normal conditions of current and weather unmooring may be carried out with the constant-heading ship remaining at anchor.

However if, in the judgement of both masters, weather and current conditions so require, the constant-heading ship should weigh her anchor and unmooring can be carried out underway, following the precautions for manoeuvring under power set out in Section 6.4.

9.7.2 Unmooring After Drifting Transfer or Transfer While Making Way

Where STS transfer operations have taken place while making way or drifting, it is normal to bring the combined two-ship system head to the wind before unmooring.

Sufficient crew should be allocated to unmooring stations and consideration should be given to the following points:

(a) Side of cargo transfer cleared of obstructions, including derricks or cranes. (b) Method of disengagement and of letting go mooring lines agreed. (c) Fenders, including their towing and securing lines, checked to be in good order. (d) Winches and windlass ready for immediate use. (e) Rope messengers and rope stoppers ready at all mooring stations. (f) Fire axes available at each mooring station. (g) Crew at stations. (h) Communications confirmed between ships. (i) Communications established with mooring gangs. (j) Mooring gangs instructed to let go mooring lines only as requested by the manoeuvring ship. (k) Shipping traffic in the vicinity checked.

See Check List 5.

Experience has shown that satisfactory unmooring can be achieved by singling up fore and aft, then letting go the remaining forward mooring and allowing the bow to swing away from the constant-heading ship to a suitable angle (about 5°), at which time the remaining stern mooring line is let go and the manoeuvring ship moves clear. After disengaging, neither ship should attempt to steam ahead or fall astern of the other until both ships are well separated.

After singling-up, some masters prefer to let go the aft mooring line first and then let go the remaining forward mooring line. In either case, the angle of disengagement should be small, about 5°.

10.1.1 Fender Types

Fenders used for STS transfer operations can be divided into two main types: those traditionally used by small ships in harbour and other smooth water locations, and larger, pneumatic or foam-filled fenders, used for offshore cargo transfers involving large ships.

The most common fender used for STS transfer operations is the high pressure pneumatic type. These fenders are generally favoured for their robustness and longevity. They have the additional advantage compared with their foam-filled counterparts that fender distortion occurring at unusual breaks in hull form can be easily overcome.

The low pressure pneumatic type have been found useful for emergency situations where ease of transport is a first priority. However, they can have the disadvantage of much shorter life in service.

Foam filled fenders are not commonly used but owing to lighter construction they can have advantages when used as secondary fenders. This is because secondary fenders often have to be hauled into position well above the water line and in such cases fender weight becomes an issue of importance.

At anchor in smooth waters, traditional types of fenders have been used successfully for mooring operations between small ships. Although often suitable for this purpose, it should be realised that such fenders demand restrictions on berthing methods (and locations) because of their limited impact absorption capabilities and insufficient stand-off distance.

10.1.2 Fenders for STS Transfer Operations

Fenders used in STS transfer operations offshore are divided into two categories:

Primary fenders which are positioned along the parallel body of the ship to afford the maximum possible protection during mooring and unmooring.

Secondary fenders which may be used to protect bow and stern plating from inadvertent contact during mooring and unmooring.

10.1.3 Fender Requirements

Some shipowners and STS agencies may be able to call upon past experience when assessing fender requirements for a particular STS transfer operation. It is advisable, however, to estimate the impact forces which will be generated between berthing ships and then to select appropriate fenders. Information published by fender manufacturers will prove useful in selection. The table provided in this section gives guidance when deciding on fender requirements for a particular transfer.

** Single point contact can occur. It describes a berthing operation where the manoeuvring ship lands at an angle to

the other ship thus involving initial contact on just one fender. It is not a recommended manoeuvre but experience suggests that fender requirements should be geared to accommodate such an eventuality.

This table is intended as a guide in deciding the fendering required for a particular transfer. When an organiser is arranging a particular operation, reference should be made to individual fender manufacturers' specifications and this should be addressed in terms of sea and swell conditions amongst other factors. Guidance on the use of fenders should also be consulted in order to determine if the fenders are suitable in terms of energy absorption and stand-off capability.

This latter point is very important for many of the larger gas carriers which tend to have "finer" hull- forms. Accordingly, as can be seen from the above table, ships over some 20,000 tonnes displacement are recommended to be fitted with fenders of at least 3.3 m diameter.

10.1.4 Fender Positioning

Fenders should be rigged alongside and positioned according to an agreed plan taking into account the length of each ship, their parallel-body distances and the positions of on-board cargo manifolds. Fender positions should be such that the impact force, due to berthing, will be distributed widely over the hull of both ships, having regard to the spacing and suitability of internal strength members. Primary and secondary fenders should be positioned to afford the maximum possible protection during mooring and unmooring.

10.1.5 Fender Handling

On dedicated ships, fenders are often stowed on board in special cradles and handled by special davits.

Established ships can be expected to have local arrangements for fender handling.

As necessary, non-dedicated ships will be able to use the normal shipboard derricks or cranes when handling fenders. However, in many cases this will not be necessary as the STS agency should provide a suitable service craft for manoeuvring this equipment into position.

Floating fenders should be fitted with strong fore and aft securing lines or pennants. When fitted to the manoeuvring ship the pennants should be suitably deployed for towing during berthing operations.

10.2.1 Hose Standards

The hoses used for handling LPG should be specially designed and constructed for the product and for the maximum pressures expected.

Rubber hose is generally considered suitable for temperatures down to -20°C and some modern designs are suitable down to -50°C. Such hoses should be manufactured to BS 4089 Type 3 (-20°C) or Type 5 (-50°C) standard having a maximum recommended working pressure of 27.5 Bar.

When a fully refrigerated cargo transfer is to take place, pressures will be lower but temperatures may reduce to -50°C. Accordingly, under such circumstances, flexible metallic hose assemblies to BS 4089 can be supplied. As rubber based hoses of proven design for such low temperatures become more readily available then they may be used as an alternative.

Within each hose string it can be advantageous to fit a dry-break coupling. Such equipment allows a hose to break at the coupling without either overstressing the hose or allowing a gas escape to atmosphere. Dry-break couplings are particularly useful in emergency situations.

Reference is made to Section 3.3.4 on the care necessary to ensure the electrical continuity of a hose.

10.2.2 Hose Size and Length

The diameter of a chosen cargo transfer hose is governed mainly by the required transfer rate and some detail on this subject is given in Section 8.4. However hoses in excess of 12 inches in diameter will be progressively more difficult to handle and particular care will be needed to avoid damage from kinking.

Hose lengths should be adequate to allow for differences in cargo manifold height, fore and aft alignment and other differential movements throughout cargo transfer.

10.2.3 Handling of Hose

During transportation, hoses should be handled with great care and it is often preferable that they be crated. During hose lifting on board ship, it is vital that they be properly supported in at least two positions to avoid kinking.

See Section 8.1 for guidance on calculating the minimum bending radius of hoses.

Reference is also made to Sections 7.5.2 and 3.3.4 on the fitting and handling of insulating flanges.

10.2.4 Hose Inspection and Testing

Hoses used should be subject to regular inspection for damage or deterioration, and when not in use they should be stowed in a sheltered location. Hoses should be pressure tested at least every six months. A record of inspection and pressure testing should be available on site.

The procedures for testing rubber hose should be in accordance with BS 4089.

10.2.5 Hose Connection

STS transfer operations require hose connections to be well made. The connection to each ship's cargo manifold should be carried out in such a way that quick release is possible. Flanges and quick- release couplings should be in good condition and properly used to ensure leak-tight connections.

The gaskets used at the ships' manifolds and between each hose should be made from compressed asbestos fibre. This applies to cargo transfers involving either pressurised or refrigerated gas. Jointing materials such as cork, rubber or plastic should be avoided.

To simplify hose connection, it is recommended that ships be fitted with cargo manifolds designed in accordance with Recommendations for Manifolds for Refrigerated Liquefied Gas Carriers for Cargoes from 0°C to Minus 104°C (see References). These recommendations also provide information on cargo flange size, manifold strength (to cope with the extra forces) and the detail necessary for constructing hose support arrangements at the ship's side.

10.2.6 Tools

Small tackles, slings, nuts, bolts, gaskets and other items of equipment used for connecting hoses should be kept in a container on the dedicated, established or non-dedicated ship. The container should be suitable for transferring between the ships. This equipment should be readily available throughout cargo transfer.

10.3.1 Mooring Lines

A ship's standard complement of mooring lines is generally suitable for STS transfer operations but ships equipped with steel wire mooring lines should fit soft rope tails to them.

It is customary to use mooring lines from the manoeuvring ship but it may be necessary to supplement these with lines from the other ship.

10.3.2 Soft Rope Tails

All ship to ship mooring lines made of steel wire rope should be insulated to stop the flow of ship to ship electric currents. This is done by attaching a soft rope tail of synthetic material to the eye of each steel mooring wire. Ships fitted with synthetic mooring lines (such as nylon) will use the natural properties of soft moorings to similar effect.

Soft rope tails should be of adequate length to introduce a degree of elasticity into the mooring system. They should also be of equivalent strength to the wire to which they are fitted. To avoid electrical contact at fairleads between a ship and steel wire rope, soft rope tails should not be less than 10 m in length.

Soft rope tails fitted to wire moorings also introduce the benefit of making the cutting of mooring lines easier in an emergency. For this purpose, long-handled firemen's axes should be available at all mooring stations.

10.3.3 Rope-Messengers and Heaving Lines

A rope messenger is a rope of adequate length and size (see Section 10.8) which is used for hauling mooring lines between ships.

Where possible, heaving lines and rope messengers should be made of buoyant materials. An adequate number of each should be provided.

10.3.4 Mooring Fairleads

It is recommended that all fairleads used during STS transfer operations are of an enclosed type which will remain effective for controlling mooring lines as the freeboard difference between the two ships changes. Such fairleads should be strong enough to take the anticipated mooring loads and large enough to allow the mooring line (plus any soft rope tail and shackle) to pass through comfortably.

Effective leads between fairleads, mooring bitts and mooring winches should be available for the handling of all mooring lines.

Appropriate fairleads should be fitted to each ship in order to accommodate a mooring pattern similar to that shown in the Figure 1 (see Section 6.3). Apart from the need for headlines, sternlines and breastlines, some special needs for springlines have to be considered. It has been found that enclosed fairleads for spring lines need to be positioned no more than 35 metres forward and aft of the cargo manifold.

10.3.5 Mooring Bitts

It is recommended that all liquefied gas carriers be fitted with an array of mooring bitts of sufficient strength on each side of the ship. A set of bitts should be positioned between each enclosed fairlead and its attendant winch in order to accommodate an acceptable mooring arrangement such as that illustrated in Section 6.3.

In general it is recommended that the transfer of personnel between ships be kept to an absolute minimum and much can often be accomplished by transferring paperwork by heaving line. Where it is found necessary to transfer personnel the preferred option is usually to use the stand-by launch - but only during periods when cargo transfer has stopped. If no tug or other craft is available to transfer essential personnel from one ship to the other, a lightweight gangway, complete with safety net should be made available by either ship to provide safe access between them (see also the precautions in Section 3.3.4.2). The use of open-rung ladders is not recommended: gangways should be used.

The shipboard oil pollution emergency plan (SOPEP) for both ships should be activated in case of an oil spill.Also, the support craft should be provided, as appropriate, with a locally approved oil dispersant. This isparticularly important in relation to bunker spillage.

During STS transfers at night, normal in-port deck lighting will be adequate. Portable spotlights, whichshould be flameproof, and bridgewing spotlights are useful for night mooring and unmooring operations.

Hand-held radios are invaluable for inter-ship communications during mooring and cargo transfer operations. Inter-ship confirmation should be sought that the portable radios on each ship are capable of working on the same frequencies.

For established ship and dedicated ship operations, it is common practice for that ship to supply all portable radios required for cargo transfer operations and, accordingly, to supply the necessary additional radios to the other ship.

The table below outlines the equipment which might be available for an STS transfer operation. The table takes as an example an intended STS transfer operation between two ships of about 65,000 tonnes deadweight.

An emergency on either ship should be indicated immediately by sounding the emergency signal. All personnel should then proceed as indicated by the contingency plan (see Section 11.3). It is emphasised that both ships should be in an advanced state of readiness at all times in order to be in a position to deal with emergencies.

The emergency signal should be agreed between both ships and this should be a series of short rapid blasts on the ship's whistle or siren. It should be sounded by either ship in an emergency or in case of communication breakdown during cargo operations.

The following arrangements should be made on both ships:-

At all times, ships should have their main engines ready for immediate use. Emergency Shut-Down (ESD) pendant control boxes should be led from one ship to the other. ESD systems should be tested prior to cargo transfer.* Ships should be prepared to disconnect hoses at short notice. Soft rope tails should be fitted to wire moorings so making cutting easier in an emergency. Extra mooring lines should be provided at mooring stations as replacements in case of breakage. Axes should be placed at mooring stations for quick release of mooring lines. Fire fighting equipment should be ready for immediate use.

* Valve closing times should be checked and tested with a view to the prevention of pressure surge when an ESD is activated (see also Sections 7.3 and 11.6.3).

Although STS transfer operations can be carried out safely, the risk of accident and the potential scale of the consequences require that organisers develop contingency plans for dealing with emergencies. Such plans should cover all possible emergencies and should provide for comprehensive response. In addition, contingency plans should have relevance to the location of the operation and should take into account the resources available both at the transfer area and with regard to nearby back up support. Where appropriate, the contingency plan should be integrated with similar plans prepared by the responsible local authority.

A contingency plan is a collation of individual emergency procedures. It is agreed between both ships before STS transfer operations commence. It should outline specific emergency duties for all ships' personnel.

Chapters for inclusion in a contingency plan can include:

Fire on either ship. Gas escape or leakage. Mooring line failure. Communication failure. Hose failure. Hose quick release arrangements. Fender burst. Operational weather limits. Emergency departure procedure. Oil pollution from bunkers. Injuries to personnel (frost burns, suffocation etc.).

Generally, in an STS transfer operation, the dedicated ship, established ship or non-dedicated ship will be playing the leading role. Accordingly, where organisers have delegated the preparation of a contingency plan, it will normally be incumbent on the master of such a ship to establish the overall plan and make a copy available to the other ship. Further guidance on these matters is available from References 5 and 6.

It is difficult to anticipate every emergency which could arise and therefore almost impossible to indicate precise remedial action. However, mooring line failure and fire on either ship are examples of the more likely risk scenarios which organisers should include in the contingency plan.

In an emergency, the masters involved should assess the situation and act accordingly, bearing in mind that unduly hasty decisions could worsen the emergency. The following actions should be taken, or considered, in the event of any emergency arising during an STS transfer operation:

Sound the emergency signal. Alert crews on both ships. Initiate emergency procedures. Stop the transfer (activate BSD Systems). Man emergency stations. Send mooring gangs to stations. Purge cargo hoses with nitrogen. Disconnect cargo hoses. Confirm the ship's main engine is ready for immediate use.

In addition, masters should decide jointly, particularly in cases of fire, whether it is to their mutual advantage for the ships to remain alongside each other.

It may be found appropriate to include the basic actions, as listed above, in individual contingency plans, as prepared for individual operations. However, it is stressed that these are only examples of major items for consideration.

Despite careful attention to safety procedures, emergencies can occur. Often such events can be contained and their effects minimised by preparing ship's crews, through a system of drills, to deal with a variety of emergencies.

For STS transfer operations involving either a dedicated ship or an established ship, the master of this ship should exercise the crew frequently in fire fighting and safety drills. Drills should include demonstrations of fire fighting and safety equipment. Emergency stations and duties should be established, explained to the personnel concerned and displayed prominently. When crew members are changed, the replacements should be integrated into the team. The appointment of a ship's officer responsible for safety helps to maintain continuity, allows better arrangements for drills and provides better coverage for updating emergency procedures.

11.6.1 Emergencies During Manoeuvring

The masters of both ships should always be prepared to abort a berthing operation if necessary. The decision should be taken in ample time while the situation is still under control. The masters of both ships should be immediately informed of each other's actions. The International Regulations for Preventing Collisions at Sea must be complied with.

11.6.2 Procedures for Communication Failure

If communication breakdown occurs during approach manoeuvres, the manoeuvre should be aborted (see Section 4.8) and subsequent actions taken by each ship should be indicated by the appropriate sound signals as prescribed in the International Regulations for Preventing Collisions at Sea.

During cargo operations, in the event of a breakdown of communications on either ship, the emergency signal should be sounded and all operations suspended immediately.

In general, operations should not be resumed until satisfactory communications have been re- established.

11.6.3 Activation of Emergency Shut Down (ESD) Systems

Liquified gas carriers are fitted with ESD systems for the closure of principal cargo valves and the stoppage of cargo pumps. ESD actuators are fitted in appropriate deck areas to provide a quick shut- down in case of emergency.

Where ships have been fitted with pendant controls for emergency shut-down then these should be passed to the other ship. By this means both ships can have executive control of emergency shut- down of all cargo pumping operations. The closing times of manifold valves should be checked as being within 30 seconds, consistent with ensuring that dangerous pressure surges will not occur due to the valve closing too quickly.

The mode of operating the ESD system should be agreed between the ships taking into account the need to avoid damage to the cargo hose. It is always preferable that the discharging ship's ESD system is the first to be activated.

11.6.4 Procedures for Gas Accumulation on Deck

An STS transfer operation should be suspended if there are excessive cargo vapours around the decks, manifold or vents of either ship and should not be resumed until after the cargo vapour leak or release has been stopped and all gas has dispersed (see also Section 3.3.7).

11.6.5 Accidental Cargo Release

Any leakage or spillage should be reported immediately to the officer in charge who should stop the cargo transfer.

An STS transfer operation should be suspended if there is any spillage on either ship and should not be resumed until after the vapour has dispersed.

Throughout all cargo transfers, no unauthorised craft should be allowed alongside either ship or within a pre-set exclusion zone set at a safe distance. It would be normal to exclude such craft from within a 500 metre range. For operations involving either an established ship, dedicated ship, or non- dedicated ship, although service craft may be allowed alongside from time to time under controlled circumstances, it is recommended that they stand by beyond the exclusion zone.

On a non-dedicated ship the crew should be made fully aware of all emergency procedures. In addition, anemergency drill should be held within the 24 hours preceding an STS transfer operation.

11.6.6 Oil Pollution Control

Risk of oil pollution during STS transfer operations is no greater than during in-port cargo transfers. However, as a transfer area may be out of range of port services, a shipboard oil pollution emergency plan (SOPEP) to cover such risk should be available. When appropriate, as in the case of the lighter fuel oils, such plans should include the treatment of oil pollution resulting from damage to bunker tanks by applying locally approved oil dispersants (see Section 10.4).

This guide may be of assistance when considering the provision of emergency STS transfer operations to ships aground. However, in each unique situation, the procedures adopted may vary from this guidance according to circumstances on a case by case basis.

REFERENCES

1. Ship to Ship Transfer Guide (Petroleum) - (ICS/OCIMF)

2. Tanker Safety Guide (Liquefied Gas) - (ICS)

3. International Safety Guide for Oil Tankers and Terminals (ISGOTT) - (ICS/OCIMF/IAPH)

4. International Regulations for Preventing Collisions at Sea - (IMO)

5. Contingency Planning and Crew Response Guide for Gas Carrier Damage at Sea and in Port Approaches, 1989 - (ICS/OCIMF/SIGTTO)

6. Guide to Contingency Planning for the Gas Carrier Alongside and within Port Limits, 1987 - (ICS/OCIMF/SIGTTO)

7. Standard Marine Communication Phrases - (IMO)

8. Hose and Hose Assemblies for Liquefied Petroleum Gas - (BS 4089)

9. Recommendations for Manifolds for Refrigerated Liquefied Gas Carriers for Cargoes from 0°C to Minus 104°C, 1987 - (OCIMF)

10. Liquefied Gas Handling Principles on Ships and in Terminals, 1986 - (SIGTTO)

APPENDIX 1

OPERATIONAL

SAFETY CHECK LISTS

APPEND IX 2

Part-Reproduction of the

INTERNATIONAL

SHIP/SHORE SAFETY CHECK LIST

as it refers to STS Transfer Operations

This Appendix shows check lists as taken from the International Safety Guide for Oil Tankers and Terminals (ISGOTT).

As reproduced, the first check list (Part 'A') has been truncated to exclude questions on crude oil washing and inert gas systems. Part 'C' for bulk liquefied gases has been included in full but Part 'B', covering chemicals, has been omitted as it is not relevant to this guide.

Satisfactory completion of these Check Lists is a necessary precursor to any STS cargo operation involving liquefied gas. The questions should be read as if intended for ship-to-ship operations rather than in the ship- to-terminal context as written.

DECLARATION:

We the undersigned have checked, where appropriate jointly, the items on this check list and have satisfied ourselves that the entries we have made are correct to the best of our knowledge.

We have also made arrangements to carry out repetitive checks as necessary and agreed that those items marked with the letter 'R' in the column 'Code' should be re-checked at intervals not exceeding ____hours.