OTM-7.16	Oil Tanker Manual OTM Tank Cleaning Docking and Repairs	Doc No.: OTM 7.16 Revision: 01 Date: 15 Oct 2024 Issued by: DPA Approved by: MD

TANK PREPARATION PLAN FOR REPAIRS AND DRY DOCK

Cargo tank preparation planning for repair and dry-docking periods is to start well in advance and before the last discharging operation. All equipment, tools, spare parts etc. required for the cargo tank preparation should be prepared and checked in good time.

A plan detailing the cargo tank preparation is to be drawn up and discussed by the onboard management team particularly with reference to use of vessels equipment, and potential trim requirements during the operation, to make the most cost and manpower effective use of the vessels facilities.

The cargo tank preparation plan is to be sent to the marine department for review and approval.

The cargo plan preparation plan should cover all aspects of each particular operation and should have a contingency plan appended to it. In arranging the plan, consideration must be given to stress condition, trim and draught at all stages of the voyage. Any specific repair berth, /dry-dock instructions must be complied with, to the extent that the vessels safety is not adversely affected.

The plans should be prepared in conjunction with the vessel's load/stress calculations to ensure that the vessel remains within the limiting stress parameters throughout the operation.

The following should be taken into account when preparing the cargo plan:

• Last cargo carried and estimation of cargo residues
• Tank atmosphere and flammability/toxicity of last cargo
• Length of voyage and available manpower, weather conditions expected
• Geographical area of the voyage and MARPOL special areas
• Number, type, capacity of fixed and portable tank cleaning machines available
• Capacity of heater (or heating water in slop)
• Capacity of Inert gas system, gas freeing fans and dry-air plant
• Ballast condition
• Works planned in the cargo tanks as per the repair/dry-dock work list
• Cargo tank Preparation stages

The contents of the plan should include the following stages where applicable, but not be limited to:

• Crude oil washing
• Tank stripping and line draining
• Washing of cargo tanks
• Line flushing
• Purging
• Gas freeing
• Inspection, de-mucking and mopping of Cargo tanks
• Decanting

The following information should be included for each of the above steps:

• Any critical points where incorrect trim, stability or stress limitations may occur. Additionally, a series of loading computer printouts showing estimated vessel load status at various stages throughout the planned operation should be available to cross check against the vessel’s actual load status on a regular basis during the operation. Any changes needed to the plan may become more readily apparent.
• Status of Cargo and Ballast System Valves and Equipment - individual valves that are to be operated should be clearly identified for each stage of the operation. A clear statement should be made that all other valves are to remain shut. Segregation and isolation valve status should be clearly identified. Each pump to be used should be individually identified for each stage of the operation. Where blanks or bends are to be changed over, the planned status of all connected systems must be noted.
• Status of tank venting valves and Inert Gas system components - Planned IG system or vent system operating pressure to be quoted, along with instructions detailing methods to achieve this.
• Tank washing instructions – Program of tank washing must include identity of tank, details of wash cycle, and the interaction with any cargo and / or ballast operations, particularly with regard to tank ullage levels and vessel trim. Identification of drive fluid source and washings deposit tanks should be clearly made.
• Ballast operations - Program of ballast operations must include identity of tanks to be handled and details of stresses, trim and stability throughout the operations.
• Allocation of duties - This should include specific duties of the deck and engine room watch keepers ensuring strict compliance with rest hours requirements.

A diagrammatic display of information is preferred, as this aids a rapid assessment of the operational status by all concerned.

Tank preparation plan review and discussion

All officers and crewmembers, including those in the Engine Room department, who will be involved in the operations, should familiarize themselves with the relevant contents of the plan prior to the start of any operations.

Any queries about the plan or any anomalies that it may contain should be discussed prior to the plan being finalized and implemented.

It is important that a copy of the plan is available in the Cargo Control Room (C.C.R.) and Engine Control Room (E.C.R.) throughout the tank preparation operation.

The Master should also be given a copy of the operational plan.

The plan should be clear and concise so that if, due to unforeseen circumstances, the Chief Officer is indisposed for any reason then the other members of ship's staff can take over without any untoward delay.