Section 9 Structural details

9.1.1 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 by Pt 6 Hull Construction in Steel, Pt 7 Hull Construction in Aluminium and Pt 8 Hull Construction in Composite of the Rules for steel, aluminium alloy and composite materials respectively.

9.2.1 Hawse pipes, bow rollers and other deck gear, of adequate size and construction, are to be provided for handling and securing the anchors and are to be efficiently attached to the structure and arranged to give an easy lead to the cable.

9.2.2 The hawse pipes are to be of sufficient size and thickness, and arranged to give an easy lead for the cable to the windlass.

9.2.3 Hawse pipes and anchor pockets are to be of ample thickness and of a suitable size and form to house the anchors efficiently, preventing, as much as practicable, slackening of the cable or movements of the anchor being caused by wave action. The shell plating and framing in way of the hawse pipes are to be reinforced as necessary, see Pt 3, Ch 5, 9.4 Local reinforcement 9.4.1. Substantial chafing lips are to be provided at shell and deck. These are to have sufficiently large, radiused faces to minimise the probability of cable links being subjected to high bending stresses. Alternatively, roller fairleads of suitable design may be fitted. Where unpocketed rollers are used, it is recommended that the roller diameter be not less than eleven times the chain diameter. Where hawse pipes are not fitted, alternative arrangements will be specially considered.

9.3.1 Satisfactory means are to be provided to prevent inadvertent flooding of chain lockers, see Pt 3, Ch 5, 6.8 Cable locker. Spurling pipes are to be provided with permanently attached closing appliances to minimise water ingress. Examples of acceptable arrangements are:

1. steel plates with cutouts to accommodate chain links, or

2. canvas hoods with a lashing arrangement that maintains the cover in the secured position.

9.4.1 The thickness of shell plating determined in accordance with the Rule requirements is to be increased locally by not less than 50 per cent in way of hawse pipes.

9.4.2 Supports under windlasses and winches are to be suitably reinforced.