SHIP ТО SHIP TRANSFER GUIDE (PETROLEUM)

(Third Edition 1997)

For Use with Crude Oil and Petroleum Products


Chapter 7

Procedures Alongside

7.1 PRE-TRANSFER PROCEDURES

When the two ships are securely moored and before cargo transfer commences, good communications should be established between the personnel responsible for cargo operations on each ship and the pre-transfer checks should be satisfactorily completed (see Check List 4). In addition, attention should be given to the appropriate safety check list from ISGOTT (see Appendix 2).

 

7.2   RESPONSIBILITY FOR CARGO OPERATIONS

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

 

7.3   PLANNING FOR CARGO TRANSFER

When preparing cargo loading and discharging plans, due regard should be given to ensuring that adequate stability is maintained, hull stresses remain within seagoing limits and free surface effects are kept to a minimum throughout.

 

The cargo transfer operation should be planned and agreed in writing between the two vessels and should include information on the following where applicable.

quantity of each grade of cargo;

sequence of grades;

cargo density and temperature;

details of cargo transfer system, number of pumps, maximum pressure;

crude oil washing procedures;

cargo heating requirements;

initial, maximum and topping off rates;

notice of rate change and transfer shutdown procedures;

emergency and spill containment procedures;

watch or shift arrangements;

critical stages of the operation; and

local or government rules that apply to the transfer.

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.

 

The agreed transfer rate should not exceed the manufacturers recommended flow rates for the cargo hoses (see Section 9.2.6).

 

7.4   CARGO TRANSFER - GENERAL REQUIREMENTS

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

 

Cargo transfer should begin at the agreed slow rate to enable the receiving ship to check that the cargo pipeline system is correctly set. The transfer rate should also be reduced to an agreed topping off rate when the receiving ship's tanks are reaching their filling limits. Throughout the transfer, regular hourly transfer rate checks and comparisons should be made between the two vessels, and the results logged. Any differences or anomalies should be carefully checked and if necessary cargo operations should be suspended until the differences are resolved.

 

Unless the ship's design dictates otherwise, cargo operations should be conducted with the ullage, sounding, and sighting ports securely closed. In some parts of the world vapour balancing procedures are enforced and due regard should therefore be given to local regulations.

 

It should be noted that the incorrect operation of pumps and valves can produce pressure surges in a pipeline system. These surges can be sufficiently severe to damage the pipeline or the hoses. Consideration should be given to the prevention of pressure surges by careful planning and control of pump speeds and the operation of valves.

 

Static accumulator cargoes will require extra precautions and ISGOTT should be referred to when handling this type of cargo.

 

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

 

Many modern vessels engaged in S TS operations are fitted with segregated ballast tanks. However cases may arise where older vessels are employed which may require the transfer of ballast to the discharging ship. During deballasting from cargo tanks the inert gas system, where fitted, should be operated.

 

Regardless of the type of vessel, any ballast which is discharged overboard should be clean. All other ballast should be retained on board or, as in the circumstances mentioned above, may be transferred to the discharging ship. On completion ofdeballasting, lines and pumps should be drained, and all sea valves tightly shut, checked and sealed.

 

7.5   OPERATIONS AFTER COMPLETION OF CSRGO TRANSFER

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

all hoses drained into one ship prior to disconnecting;

hoses disconnected, taking precautions to ensure that no liquid is left in the cargo transfer system;

cargo manifolds and cargo hos^s securely blanked; and

authorities informed of completion of cargo transfer and the anticipated time of unmooring.

7.6   CARGO DOCUMENTATION REQUIREMENTS

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


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