Joint agreement on readiness to load or discharge

Before starting to load or discharge cargo or ballast, the responsible ship's officer and the terminal representative must formally agree that both the ship and the terminal are ready to do so safely.

Supervision

The following safeguards must be maintained throughout loading and discharging:—

A responsible officer must be on duty and sufficient crew on board to deal with the operation and security of the ship. A continuous watch of the tank deck must be maintained. If a ship's cargo control room, from which all operations can be controlled, does not have an overall view of the tank deck, then a competent member of the ship's crew must be continuously on watch on the tank deck.

A senior terminal representative must be on duty and communications between him and the responsible ship's officer continuously available.

A competent member of the terminal organisation should be on continuous duty in the vicinity of the cargo connections. Supervision should be aimed at preventing the development of hazardous situations. If, however, such a situation arises, the controlling personnel should have adequate means available to take corrective action. Supervision by systems incorporating television should only be used where they give effective control over the cargo operations and these systems cannot be regarded as satisfactory when cargo operations are at a critical phase or during adverse weather conditions.

The agreed ship-to-shore communications system must be maintained in good working order.

At the commencement of loading or discharging, and at each change of watch or shift, the responsible ship's officer and the terminal representative must each confirm that the communications system for the control of loading and discharging is understood by them and by other personnel on duty.

The stand-by requirements for the normal stopping of shore pumps on completion of loading and the emergency stop system for both the ship and terminal must be fully understood by all personnel concerned.

Checks during cargo handling

At the start of and during cargo handling, frequent checks should be made by the responsible officer to confirm that cargo is only entering or leaving the designated cargo tanks and that there is no escape of cargo.

6.2 DESIGN CONSIDERATIONS

6.2.1 The terminal

During the design of a new marine terminal, minimum and maximum ship size is established. Furthermore, the jetty and its equipment are designed accordingly. Farther off-shore, the port approaches and river channel are surveyed. Once a terminal is ready for service, the relevant information needed by visiting ships should be advised to the port authority, ships' agents, pilots and shipowners' associations. (Reference 2.41).

In the case of a change to an existing facility it may be necessary to either amend the original design parameters or accept a new class of ship having different char­acteristics from those originally envisaged. If, as a consequence, modifications are made to the jetty facilities, the appropriate details should be advised to the same group of organisations.

It is good practice for terminals to audit their marine facilities from time to time and in this respect, Marine Terminal Survey Guidelines (References 2.15) can be of benefit. Reference 2.18 may also be consulted with advantage.

6.2.2 The ship

Gas carriers are normally built in such a way that there is maximum compatibility with a range of terminals. Compatibility of any particular ship and terminal should always

be confirmed from a technical viewpoint by terminal personnel prior to acceptance of any nomination. Confirmation should include items such as mooring studies, manifold configurations and ESD link compatability (see 6.3.1).

6.3 COMMUNICATIONS

Communications should start before the intended voyage and continue until the arrival of the ship alongside: they must also include the period of cargo operations and continue until the ship departs. All communications should be carried out in a common language so that misunderstanding cannot develop. Usually, apart from some coastal trades, this will be English. (Reference 2.31).

6.3.1 Prior to charter

Prior to chartering a ship, in order to ensure a suitable match of ship and jetty, it is necessary for the parties concerned to exchange information. From a terminal's viewpoint, it is important for operations personnel to have a clear understanding of the restrictions within the port and at the jetty which influence the maximum or minimum size of ship they are able to receive. This information should be documented and made available to their commercial departments so that only ships having suitable dimensions are received. Apart from the more obvious criteria, such as ship's length and height of manifold above the water line, other issues such as the suitability of the ship's mooring equipment and its deck layout, are often relevant. Furthermore, in the gas trades, the provision of a compatible ship/shore link can be vital.

To assist in determining the suitable matching of ship and jetty mooring equipment, on receipt of appropriate information such as the ship's mooring plan, it is often advantageous to prepare a ship/shore mooring plan showing the direction of all moor­ing line leads and to ensure that these provide maximum restraint for all weather conditions. Guidance on this matter is to be found in Mooring Equipment Guidelines (see Reference 2.17).

Such information exchange can be simplified where data has been completed in accordance with the Ship Information Questionnaire for Gas Carriers (see Reference 2.16). This referenced data is often required by a ship's time charterer and repro­ductions of the publication are sometimes referred to as Gas Form 'C'.

The use of Reference 2.16 as a pro-forma also expedites information exchange on other matters such as cargo manifold arrangements, reliquefaction capabilities, cargo pumping characteristics, cargo tank capacities and cargo segregation possibilities.

6.3.2 Prior to arrival

As a ship approaches a port, direct contact should be established between ship and shore as soon as possible. Modern communications will readily allow the terminal to update the ship on its requirements for the envisaged transfer operation. Additionally, port requirements, berthing arrangements and the facilities available can also be advised. Similarly, the shipmaster may inform the terminal of the cargo arrival temperatures and pressures, stores and bunker requirements and personnel joining or leaving.

For the planning of ship cargo operations, the shipmaster should be advised by the terminal of all port and terminal requirements relevant to gas carriers. (Reference 2.42).

6.3.3 Alongside the jetty

As for the earlier parts of a ship's voyage described in the foregoing paragraphs, reliable and effective communications are a necessity once the ship is alongside.

While alongside and transfering cargo, various means of communication need to be agreed. Decisions must be made on the use of portable radios or telephones. These tools usually form the basis of good communications under normal operating conditions. However, emergency means of communication must also be developed and this will normally take the form of an established terminal operating procedure (see Reference 2.31).

In many terminals, the actuation of emergency shut-down (ESD) valves is interlinked between ship and shore. This communication channel requires a suitable system having plugs and sockets fitted on ship and jetty. Both ship and shore need to be properly outfitted. Such methods of communication are recommended so that a con­trolled emergency shut-down can always be accomplished. This will always ensure that either the ship or shore emergency shut-down valve, whichever is nearest to the operational cargo pump, is closed first. (Reference 2.34).

6.4 DISCUSSIONS PRIOR TO CARGO TRANSFER

Before the start of any cargo transfer operation, the intended cargo handling pro­cedures must be thoroughly discussed at a meeting held between the responsible personnel from the ship and the terminal.

The purpose of the meeting is primarily to draw up a suitable cargo plan and to check on safety issues. Furthermore, the meeting has the benefit of making both sides familiar with the essential characteristics of ship and shore cargo handling systems. At the meeting, the envisaged operational and safety procedures and requirements should be covered. Finally, any limitations to be observed during the transfer should be noted in writing. Written agreements should include a cargo handling plan (including transfer rates), communication procedures, emergency signals, emergency shut-down procedure and the tank venting system to be used.

The content of the meeting will depend on a wide variety of circumstances but the following broad outline forms the normal basis for such meetings.

(i) The names and roles of terminal and ship personnel who will be responsible for cargo transfer operations should be noted.

(ii) The terminal representative should check that pre-arrival instructions to the ship on cargo, cargo disposition and cargo arrival temperature have been carried out. They also check that all necessary ship equipment inspections and tests have been performed.

(iii) Similarly, the ship's officers should satisfy themselves that the relevant terminal equipment is satisfactory and that appropriate inspection checks have been carried out.

(iv) The terminal representatives and, where necessary, customs and independent surveyors should be informed of the cargo tank data, such as:—

• Temperatures          • Liquid heel or arrival dip

• Pressures                • Composition of tank vapour, and

• Cargo tank quantities • Total quantity of cargo on board

(v) The ship and terminal should then discuss and agree in writing the quantity and types of cargo to be loaded or discharged and in what order. The anticipated transfer rates and, for discharge, the receiving tank allocations should also be agreed.

The cargo transfer operation should be planned and confirmed in writing in order to assure full mutual understanding. The items to be addressed should include:—

· The order of loading or discharging

· The total quantities of cargo to be transferred

· The sequence of discharging and receiving tanks

· The intended transfer rates

· The transfer temperatures and pressures to be expected, and

· The use of vapour return line

Simultaneous cargo and ballast handling, for stress and ship stability purposes, should also be noted on the cargo plan.

(vi) To reconfirm earlier pre-charter advice, the previous three cargoes carried by the ship and the relevant dates should be noted in order to identify and assess any possible cargo contamination problems, particularly after ammonia.

(vii) The appropriate Cargo Information Data Sheets should be provided (see Reference 2.1) and should be posted in prominent places on board the ship and within the terminal.

Similar detail for cargo inhibitors should be provided by the terminal.

(viii) A review of port and jetty regulations should be made with particular attention being paid to berth operating limits, fire-fighting capabilities and other emergency procedures. Similarly, ship regulations and emergency procedures should be communicated to terminal personnel. Particular importance should be paid to emergency shut-down valve closure times and to the agreed emergency shut-down procedures (see 6.6.4).

Equipment and procedures for normal and emergency communications between ship and terminal should be defined and understood. Where portable radios are provided, adequate spare battery capacity should be made available. A common language should be established.

(ix) Any further information or procedures relevant to the operation should be discussed.

6.5 SHIP/SHORE SAFETY CHECK LIST

When a ship is alongside, no cargo operations or inerting should commence until the international Ship/Shore Safety Check List has been completed by the ship and the terminal and it has been confirmed that such operations can be safely carried out. It is normal practice that this check list be presented to the ship by the terminal.

Recommendations on the Safe Transport of Dangerous Cargoes and Related Activities in Port Areas were revised by IMO in 1995. They refer to a comprehensive Ship/Shore Safety Check List covering the handling of bulk liquid dangerous substances with a special section for liquefied gases. It also includes guidelines for its completion. This has since been updated (see Reference 2.4) and the current version is reproduced in Appendix 3.

The Ship/Shore Safety Check List consists of Part A (Bulk Liquids — General), Part B (Additional Checks — Bulk Liquid Chemicals) — not included in this volume — and Part C (Additional Checks — Bulk Liquefied Gases). For gas carriers, Parts A and C should be fully completed.

A ship presenting itself to a loading or receiving terminal needs to check its own preparations and fitness for the safety of the intended operations. Additionally, the shipmaster has a responsibility to assure himself that the terminal operator has also made proper preparations for the safe operation of the terminal. Similarly, the terminal needs to check its own preparations and to be assured that the ship has carried out its checks and has made appropriate arrangements. The Ship/Shore Safety Check List, by its questions and its requirements for the exchange of various written agreements, is a minimum basis for performing such a mutual examination.

Some of the questions in the Ship/Shore Safety Check List are directed to considera­tions for which the gas carrier has prime responsibility. Others apply to both ship and terminal and the remainder to the terminal alone.

All items lying within the responsibility of the gas carrier should be personally checked by the ship's representative and, similarly, all items under the terminal's responsibility personally checked by the terminal representative. In carrying out their full responsi­bilities, however, both representatives, by questioning the other, by sighting of records and, by joint visual inspection, should assure themselves that the safety standards on both sides of the operation are fully acceptable. The joint declaration at the end of the Ship/Shore Safety Check List should not be signed until such mutual assurance is achieved.

The conditions under which the operation takes place may change during the process and the changes may be such that safety can no longer be guaranteed. A party noticing or causing any unsafe condition is required to take all necessary actions, which may include stopping the operation, to re-establish safe conditions. The presence of the unsafe condition should be reported to the other party and, where necessary, cooperation with the other party should be sought.

During cargo transfer operations, it is essential that the items shown on Ship/Shore Safety Check List be revisited by joint inspection at suitable intervals to ensure continued compliance. In this regard, re-inspection should be considered at intervals not exceeding six hours. Whenever such inspections take place, the check list should be endorsed by ship and shore personnel.

Guidelines for the completion of the Ship/Shore Safety Check List have been produced jointly by the oil, chemical and gas industries. As appropriate, these guidelines are annexed to Appendix 3 and contain detailed advice on each item of the check list. They are made widely available to ships and terminals through industry publications.

6.6 OPERATIONAL CONSIDERATIONS

6.6.1 Berthing and mooring

Berthing

Port and terminal authorities should establish berthing and unberthing criteria for safe operations, including limiting wind, wave, current and tide conditions. Requirements for the number and size of tugs must also be set.

Mooring

Mooring line configurations should be agreed as suitable. The initial mooring of the ship to the terminal and the subsequent tending of moorings is most important if the ship is to be safely held alongside and damage to transfer facilities and jetty prevented.

Comprehensive guidance on jetty and ship mooring design and on operational moor­ing management is given in Prediction of Wind Loads on Large Liquefied Gas Carriers (see Reference 2.13), and Mooring Equipment Guidelines (see Reference 2.17). For design and operational reasons, both terminal and ship staff should be familiar with the content of these books.

6.6.2 Connection and disconnection of cargo hoses and hard arms

Terminal equipment, such as hoses and hard arms, designed to connect with the ship's manifold are described elsewhere in this book (see 5.1) but, irrespective of the type of equipment being used, there are certain operational procedures to be considered (Reference 2.40).

• No flanges should be disconnected or blanks removed until it is confirmed that line connections are liquid-free and de-pressurised and, where possible, inerted with nitrogen or other suitable inert gas.

• Care must be taken to avoid air or contaminants entering cargo pipelines.

• The manifold area of a gas carrier is a zone where flammable vapours may be present. Therefore, care must be taken to ensure that ignition sources are eliminated from this area.

At some terminals, problems can be encountered with gas carriers due to mis-matching (in positioning or layout) of hard arms in relation to the ship's cargo manifold. As a result it may be necessary to restrict the number of connections used and, thereby, the overall cargo transfer rates. An alternative solution involving the use of short lengths of hard piping to bridge the mismatch, unless properly engineered, should be disallowed as these systems can induce unacceptable loads onto the ship's manifold piping and supports. The use of flexible cargo hoses for this purpose should also be disallowed as this procedure degrades the design parameters and security of the hard arm concept. Hose bridging should be restricted to vapour service connections only where permanent systems have been purpose designed. This is sometimes seen on hard arms where vapour return connections are provided by means of piggy-back systems. International standards for cargo connections for liquefied gases have been published in two booklets, one for LNG and the other for liquefied gas cargoes (see Referencess 2.10 and 2.11). The recognition of these standards in the design of new ships and terminals will greatly increase ship and shore compatibility.

6.6.3 Cargo tank atmospheres

Prior to any cargo transfer, the oxygen content in the ship's cargo tank vapours should be carefully checked. As stated elsewhere in this book, at these times the oxygen content should never exceed five per cent and is commonly required to be not more than two per cent by volume in tanks containing vapour only. Lower oxygen contents may be required for cargo quality purposes and some guidance on this subject is given in Table 2.3(b).

For example, products such as butadiene and vinyl chloride, which can react with oxygen to form unstable compounds, require maximum oxygen concentrations of 0.2 per cent by volume and 0.1 per cent by volume, respectively.

6.6.4 Cargo handling procedures

Cargo handling is described in Chapter Seven but procedural aspects of these operations, directly relevant to the ship/shore interface, are considered here.

All operations carried out alongside should be under the continuous supervision of experienced ship and shore personnel. These personnel should be familiar with the details, hazards and characteristics of the cargoes being handled and capable of ensuring that such operations can be safely and efficiently completed. Facilities for instant and reliable communications (such as separate telephone, portable radio or VHF) between the ship and the shore control should be provided at all times during cargo operations.

Before commencing operations, maximum cargo transfer rates have to be agreed. This should be done in accordance with vapour return specification, ship or shore reliquefaction capacity and emergency shut-down requirements. Inevitably, some of these considerations may be based on best practical estimates. Accordingly, during operations, a strict watch should be maintained on flow rates, tank pressures and temperatures. By means of ship/shore communications, adjustments to initial agree­ments can be made as appropriate.

If cargo transfer operations need to be stopped, this should be carried out under previously agreed controlled conditions with proper communication. If the situation demands an emergency shut-down, the agreed procedure should be followed, bear­ing in mind the dangers of excessive surge pressures. It is particularly important to maintain appropriate communication in emergency conditions and, if the responsible person becomes over-occupied in controlling operations, the communication task should be delegated to another officer.

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