Section 1 General

1.1.1 This Chapter applies to pontoons used for providing buoyant support for ship-to-shore ramps forming part of a linkspan and which are intended for operation in protected waters (see Pt 1, Ch 2, 1.2 Application 1.2.5).

1.1.2 For pontoons intended for operation in inland waterways, longitudinal strength calculations are to be carried out in accordance with the relevant requirements of the Rules and Regulations for the Classification of Inland Waterways Ships, July 2022.

1.1.3 Where required, pontoons are to be fitted with adequate arrangements for towing. In general, such arrangements are to consist of, or be equivalent to, not less than two sets of bollards, each set being suitable for accepting a towline of suitable breaking strength, see also Pt 3, Ch 10 Towing and Lifting Arrangements.

1.1.4 Where it is intended to lift a pontoon, the relevant requirements of Pt 3, Ch 10 Towing and Lifting Arrangements are to be complied with.

1.1.5 For pontoons with an L > 6D (see Pt 3, Ch 4, 1.3 Symbols and definitions 1.3.1), longitudinal strength calculations are to be carried out in accordance with the Rules and Regulations for the Classification of Ships, July 2022, Pt 3, Ch 4 Pontoons where the ship service factor, f₁, is to be taken as 0,5.

1.1.6 Pontoons that are submerged to act as buoyancy chambers will be specially considered taking into account the increase in hydrostatic pressure. Stability must also be considered for this type of buoyant arrangement.

1.1.7 Pontoons which are designed to take the ground will be specially considered.

1.2.1 Reference is to be made to Pt 3, Ch 1, 8 Information required for approval regarding information to be submitted for approval.

1.3.1 The Rule length, L, is to be taken as the overall length for square ended pontoons, or for pontoons with swim ends L need not exceed 97 per cent of the extreme length at the waterline at maximum working draught condition, L ₁, see Figure 4.1.1 Pontoon dimensions.

1.3.2 Breadth, B, is the greatest moulded breadth, in metres.

Figure 4.1.1 Pontoon dimensions

1.3.3 Depth, D, is measured, in metres, at the middle of the length, L, from top of bottom plating to top of the deck plating at side on the uppermost continuous deck.

1.3.4 Draught, T, is the maximum working draught, in metres, measured from top of bottom plating.

1.3.5 Head, h, in metres, is to be taken as:

1. for bottom longitudinals, frames, girders and transverses: the depth D

2. for side longitudinals:

   the distance of the longitudinal below the deck at side, but not less than 0,01L + 0,7

3. for side frames and transverses:

   the distance from the mid-point of span to the deck at side, but not less than 0,01L + 0,7

4. for weather deck longitudinals and transverses: a head of 0,01L + 0,7.

1.4.1 Pontoons used for this application may be longitudinally or transversely framed.