Section 5 Movable decks

5.1.1 Movable decks other than those described in Pt 7, Ch 5, 5.1 Classification 5.1.2 are not a classification item, although consideration must be given to associated supporting structure. Where movable decks are fitted, it is recommended that they be based on the requirements of this Section.

5.1.2 At the Owner's or Builder's request, however, movable decks will be included as a classification item, and the class notation Movable decks will be entered in the Register Book. In such cases, all movable decks on board the ship are to comply with the requirements of this Section.

5.2.1 Movable decks are generally to be constructed as pontoons comprising a web structure with top decking. Other forms of construction will be individually considered.

5.2.2 Positive means of control are to be provided to secure decks in the lowered position.

5.2.3 The decks are to be efficiently supported, and hinges, pillars, chains or other means (or a combination of these) are to be designed on the basis of the imposed loads. Where supporting chains and fittings are required, they are to have a factor of safety of at least two on the proof load.

5.2.4 Plans showing the proposed scantlings and arrangements of the system are to be submitted.

5.2.5 Where it is proposed to stow the pontoons on deck, when not in use, details of the proposals for racks, fittings, etc. are to be submitted for consideration.

5.3.1 Details of the deck loading resulting from the proposed stowage arrangements of vehicles are to be supplied by the Shipbuilder. These details are to include the axle and wheel spacing, the wheel load, type of tyre and tyre print dimensions for the vehicles. For design purposes the wheel loading is to be taken as not less than 3,0 kN, see Pt 7, Ch 5, 3 Vehicle decks.

5.3.2 Where it is proposed also to use the decks for general cargo, the design loadings are to be submitted for consideration.

5.4.1 The scantlings and arrangements of removable decks are to be not less than those required by the Rules for the supporting structure in which the movable decks are fitted. In general the end fixity of primary stiffening members is to be taken as simply supported. Local and secondary stiffening members may be either partially or fully fixed at their end connections dependent upon the proposed arrangement.

5.5.1 Where wheeled vehicles are to be used, the supporting arrangements are to be such that the movement at the edge of one pontoon relative to the next does not exceed 50 mm during loading or unloading operations.