Section 5 Structural details

5.1.1 Special attention is to be paid to structural continuity. Abrupt changes of shape or section, sharp corners and points of stress concentration are to be avoided.

5.1.2 Where practicable, pillars and bulkheads should be placed in the same vertical line. Beam slots in girders, etc. in way of pillars, are to be collared.

5.2.1 Hatchways and other openings in strength and ‘tween decks are to have rounded corners.

5.2.2 Manholes, lightening holes and other cut-outs are to be avoided in way of concentrated loads and areas of high shear stress. In particular, manholes and similar openings are not to be cut in vertical or horizontal diaphragm plates in narrow cofferdams within one third of their length from either end, nor in floors or double bottom girders close to their span ends, or below the heels of pillars, unless the stresses in the plating are calculated and found acceptable.

5.2.3 Openings may require to be suitably framed and stiffened.

5.2.4 Air and drain holes, notches and scallops are to be kept at least 200 mm clear of the toes of end brackets and other areas of high stress. Openings are to be well rounded with smooth edges.

5.3.1 Welding of fairlead stools, mouldings and other fittings to the top edge of the sheerstrake within 0,5L amidships, is to be avoided where possible. Bulwarks in this region should also be kept clear of the top edge of the sheerstrake, however, where welding on the top edge of the sheerstrake cannot be avoided, care is to be taken to minimise any notch effects.

5.3.2 Where a rounded gunwale is adopted, arrangements are to be made to ensure a smooth transition from rounded gunwale to angled gunwale.

5.3.3 Bilge keels, where fitted, are to be attached to a continuous ground bar, welded to the shell. The butts of bilge keels and ground bar should be completed before the bilge keels are welded to the shell. The ends of bilge keels are to be well sniped and arranged to land in way of an internal stiffener.

5.3.4 The quality of welding and general workmanship of fittings and attachments is to be equivalent to that of the main hull structure.