Section 5 Fore and aft end arrangements

5.1.1 The requirements in respect of the general constructional arrangements for mono-hull craft covered by the Rules are contained within this Section.

5.2.1 The Rules provide for both longitudinal and transverse framing systems.

5.3.1 Suitable scarfing arrangements are to be made to ensure continuity of strength and the avoidance of abrupt structural changes.

5.3.2 Where longitudinal framing terminates and is replaced by a transverse system, adequate arrangements are to be made to avoid an abrupt changeover. Where a forecastle is fitted extending aft of 0,15L from the F.P., longitudinal framing at the upper deck and topsides is generally to be continued forward of the end bulkhead of this superstructure.

5.4.1 All sea-going craft are to be fitted with forecastles, or increased sheer on the upper deck or equivalent, such that the distance from the summer load waterline to the top of the exposed deck at side at the F.P. is not less than:

where

d1	=	draught at 85 per cent of the depth D, in metres
Awf	=	waterplane area forward of at draught d1 , in m2.
B	=	moulded breadth, in metres
Cb	=	block coefficient as defined in the Load Lines Convention
Cwf	=	the waterplane area coefficient forward of
Cwf	=
H b	=	minimum bow height
L L	=	Load Line length, in metres

5.4.2 Craft which are designed to suit exceptional operational requirements, restricted in their service to Group G1, or of novel configuration will be specially considered on the basis of the Rules.

5.4.3 Where the bow height required in Pt 3, Ch 2, 5.4 Minimum bow height and reserve buoyancy 5.4.1 is obtained by sheer, the sheer shall extend for at least 15 per cent of the length of the craft measured abaft the forward end of L _L. Where it is obtained by fitting a forecastle, the forecastle shall extend from the stem to a point at least 0,07L _Labaft the forward end of L _L, and shall be enclosed.

5.4.4 Craft shall have additional reserve buoyancy in the fore end in accordance with the Load Lines Convention.

5.5.1 In general the bow crumple zone is that space forward of the collision bulkhead. Passenger and crew accommodation and the carriage of fuel and other oils are not permitted in the bow crumple zone.

5.6.1 Except for craft with G2 service notations, additional strengthening of bottom forward may be required for seagoing craft with rule length, L _R, greater than 65 m. Details are to be submitted for consideration.

5.7.1 Where a bulbous bow is fitted, the structural arrangements are to be such that the bulb is adequately supported and integrated into the fore peak structure.

5.7.2 At the fore end of the bulb the structure is generally to be supported by horizontal diaphragm plates spaced generally 1,0 m apart in conjunction with a deep centreline web.

5.7.3 In general, vertical transverse diaphragm plates are to be arranged in way of the transition from the peak framing to the bulb framing.

5.7.4 In way of a wide bulb, additional strengthening in the form of a centreline wash bulkhead is generally to be fitted.

5.7.5 In way of a long bulb, additional strengthening in the form of transverse wash bulkheads or substantial web frames spaced about five frame spaces apart are generally to be fitted.

5.7.6 The shell plating is to be increased in thickness at the fore end of the bulb and in other areas likely to be damaged by the anchors and chain cables. The increased plate thickness is to be the same as that required for plated stems.

5.8.1 Where a craft has pronounced flare or rake of bow, the structure in the forward region will be subject to special consideration, and the scantlings and arrangements may require additional strengthening.