Annex - Unified Interpretations Relating to the Protocol of 1988 Relating to the International Convention on Load Lines, 1966
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC.1/Circular.1535/Rev.2 - Unified Interpretations Relating to the Protocol of 1988 Relating to the International Convention on Load Lines, 1966 – (9 May 2022) - Annex - Unified Interpretations Relating to the Protocol of 1988 Relating to the International Convention on Load Lines, 1966

Annex - Unified Interpretations Relating to the Protocol of 1988 Relating to the International Convention on Load Lines, 1966

Regulation 13 – Position of hatchways, doorways and ventilators

1 For the purpose of these regulations, two positions of hatchways, doorways and ventilators are defined as follows:
  • Position 1 – Upon freeboard decks and raised quarterdecks, or other exposed decksfootnote lower than one standard height of superstructure above the freeboard deck, and upon exposed decksfootnote situated forward of a point located a quarter of the ship's length from the forward perpendicular that are located lower than two standard heights of superstructure above the freeboard deck.

  • Position 2 – Upon exposed decksfootnote situated abaft a quarter of the ship's length from the forward perpendicular and located at least one standard height of superstructure above the freeboard deck and lower than two standard heights of superstructure above the freeboard deck.

Upon exposed decksfootnote situated forward of a point located a quarter of the ship's length from the forward perpendicular and located at least two standard heights of superstructure above the freeboard deck and lower than three standard heights of superstructure above the freeboard deck.

Regulation 20 – Air pipes

2 Where air pipes to ballast and other tanks extend above:
  • .1 the freeboard deck; or

  • .2 other exposed decksfootnote lower than two standard heights of superstructure above the freeboard deck,

the exposed parts of the pipes should be of substantial construction, and the height from the deck to the point where water may have access below should be at least:
  • .1 760 mm on the freeboard deck or other exposed decksfootnote lower than one standard height of superstructure above the freeboard deck; and

  • .2 450 mm on other exposed decksfootnote lower than two standard heights of superstructure above freeboard deck.

Note: Flush bolted access covers, which are of substantial construction and are secured by gaskets and closely spaced bolts to maintain water tightness, are not subject to the minimum sill height requirements.

Regulation 27 – Types of ships

Regulation 27(13)(e)

3 Openings include ventilators (complying with regulation 19(4) of the International Convention on Load Lines, 1966) that for operational reasons have to remain open to supply air to the engine-room, emergency generator room or closed ro-ro and vehicle spaces (if the same is considered buoyant in the stability calculation or protecting openings leading below) for the effective operation of the ship. Where it is not technically feasible to treat some closed ro-ro and vehicle space ventilators as unprotected openings, Administrations may allow an alternative arrangement that provides an equivalent level of safety.

Regulation 37 – Deduction for superstructures and trunks

Regulation 37(3)

4 For ships assigned a type "B" freeboard, including reduced type "B", if the effective length of a forecastle is less than 0.07 L, a superstructure deduction cannot be applied to the ship.

For example, if the ship has no forecastle, or the effective length of the forecastle is less than 0.07 L, and has other superstructure, no superstructure deduction is to be applied.

In case the ship has a full superstructure (one that extends from AP to FP, per regulation 3(10)(h) of Annex B of the 1988 Load Lines Protocol), the deduction for a superstructure may be applied in accordance with regulation 37(1) of Annex B of the 1988 Load Lines Protocol.


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