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.