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The basis for safe and efficient cargo handling operations begins during the ballast voyage. For each cargo voyage, the vessel must be able to demonstrate that it has been maintained in a 'seaworthy' condition throughout and has done everything necessary for the proper care of the cargo. To do this, the following should be routine practice:

  • Maintain a record system covering all tanks and cargo related equipment, including the dates and times of all inspections, nature of tests conducted, condition of the equipment or tank, and repairs or other corrective action taken to correct any defects.

  • Spot check cargo tanks for sediment build up. Sediment can adversely effect cargo drainage and outturn.

  • Maintain a program of tank washing so that all tanks are regularly cleaned.

  • Test P/V valves, cargo valves, cargo pipelines, and heating coils on a regular basis. Note the results in the logbook and the preventive maintenance program, and record all repairs made.

  • Ensure that any repairs necessary to restore cargo system integrity are completed promptly.

  • Ballast water is used in tankers to increase seaworthiness and stability, equalise stress on the hull, and improve manoeuvrability and fuel economy. Some ballast plans have the additional objective of reducing vibration underway. To minimise hull stresses, ballast tanks should be filled in the order indicated by the ship's ballast plan, and in proper coordination with the discharge plan.
    Normal ballast plans produce a trim of between one and three meters by the stern. Careful attention to the trim of the ship can add as much as 0.5 knot to the voyage speed. A larger trim is essential for good draining while tank washing. The master is responsible for selecting a ballast plan for a safe and economic passage.

    An approximate guide for the amount of ballast suitable for different weather conditions is:
    Wind force                                  Recommended ballast tonnage
    up to 4                                             30% of DWT
    4 to 6                                               37% of DWT
    above 6                                            42% of DWT
    Ducted propellers require deeper stern drafts to reduce vibration. The ballast quantity must take account of the draft limitations of the fairway or channel, and the height limitations of overhead bridges and power cables. Required air draft may be achieved by trimming the ship by the stern rather than by adding ballast. If the master believes it safe, he can sail with CBT/SBT ballast only, without taking 'dirty' ballast into the cargo tanks.
    If no CBT/SBT capacity has been provided, ballast must be taken into dirty (or crude oil washed), cargo tanks. Such ballast becomes 'dirty ballast' and must be disposed of according to MARPOL regulations. Any oil floating on top of the ballast water may be measured and declared as pumpable cargo by surveyors.
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