14 Ballasting
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Specifications and Manuals - Crude Oil Washing Systems - Guidelines for in-port inspection of crude oil washing procedures - 14 Ballasting

14 Ballasting

  14.1 Tanks that were crude oil washed at sea will be recorded in the Oil Record Book. These tanks must be left empty between discharge ports for inspection at the next discharge port. Where these tanks are the designated departure ballast tanks they may be required to be ballasted at a very early stage of the discharge. This is for operational reasons and also because they must be ballasted during cargo discharge if hydrocarbon emission is to be contained on the ship. If these tanks are to be inspected when empty, this must be done shortly after the tanker berths. If an inspector arrives after the tanks have begun accepting ballast, the sounding of the tank bottom will not be available to him. However, an examination of the surface of the ballast water is then possible. The thickness of the oil film should not be greater than specified in paragraph 4.2.10(b) of the Revised Specifications.

  14.2 The tanks that are designated ballast tanks will be listed in the Manual. It is, however, left to the discretion of the master or responsible officer to decide which tanks may be used for ballast on the forthcoming voyage. It should be determined from the Oil Record Book that all such tanks have been washed before the tanker leaves its last discharge port. It should be noted that where a tanker back-loads a cargo of crude oil at an intermediate port into tanks designated for ballast then it should not be required to wash those tanks at that particular port but at a subsequent port.

  14.3 It should be determined from the Oil Record Book that additional ballast water has not been put into tanks which had not been crude oil washed during previous voyages.

  14.4 It should be seen that the departure ballast tanks are stripped as completely as possible. Where departure ballast is filled through cargo lines and pumps, these must be stripped either into another cargo tank or ashore by the special small-diameter line provided for this purpose.

  14.5 The methods of avoiding vapour emission where locally required will be specified in the Manual and they must be adhered to. The inspector should ensure that this is being complied with.

  14.6 The typical procedures for ballasting listed in the Operations and Equipment Manual must be observed. The inspector should ensure this is being complied with.

  14.7 When departure ballast is to be shifted, the discharge into the sea must be in compliance with regulation 9 of Annex I of MARPOL 73/78. The Oil Record Book should be inspected to ensure that the vessel is complying with this.


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