Annex – Clarification of “Major Conversion” as Defined in Regulation A-1.5 of the BWM Convention
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Statutory Documents - IMO Publications and Documents - Circulars - Ballast Water Management - BWM.2/Circular.45 – International Convention for the Control and Management of Ships' Ballast Water and Sediments, 2004 – (30 May 2013) Clarification of "major conversion" as defined in regulation A-1.5 of the BWM Convention - Annex – Clarification of “Major Conversion” as Defined in Regulation A-1.5 of the BWM Convention

Annex – Clarification of “Major Conversion” as Defined in Regulation A-1.5 of the BWM Convention

  1 Regulations A-1 of the International Convention for Control and Management of Ships' Ballast Water and Sediments, 2004 (BWM Convention) provides:

  • "4 Constructed in respect of a ship means a stage of construction where:

    • .1 the keel is laid; or

    • .2 construction identifiable with the specific ship begins; or

    • .3 assembly of the ship has commenced comprising at least 50 tonnes or 1 per cent of the estimated mass of all structural material, whichever is less; or

    • .4 the ship undergoes a major conversion.

  • 5 Major conversion means a conversion of a ship:

    • .1 which changes its ballast water carrying capacity by 15 per cent or greater, or

    • .2 which changes the ship type, or

    • .3 which, in the opinion of the Administration, is projected to prolong its life by ten years or more, or

    • .4 which results in modifications to its ballast water system other than component replacement-in-kind. Conversion of a ship to meet the provisions of regulation D-1 shall not be deemed to constitute a major conversion for the purpose of this annex."

  2 The BWM Convention does not, however, stipulate clearly whether the new installation of ballast water management systems should be treated as a "major conversion".

  3 The Marine Environment Protection Committee, at its sixty-fourth session, agreed that new installation of ballast water management systems should not be treated as a "major conversion" as defined in regulation A-1.5 of the BWM Convention.

  4 The Marine Environment Protection Committee, at its sixty-fifth session, with respect to paragraph 5.2 of regulation A-1, agreed that a change of ship type should be considered to refer to a conversion that:

  • .1 substantially alters the dimensions or carrying capacity of the ship; or

  • .2 changes the type of cargo carried through a major alteration of the ship.


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