Section 2 Deflection control

2.1 General

2.1.1 The limiting deflection requirements for plate panels and stiffening members are given in terms of limiting deflection coefficient, f _δ, see Table 7.2.1 Limiting deflection ratio. The coefficient equates to a span/deflection ratio in consistent units.

Table 7.2.1 Limiting deflection ratio

Item		Deflection ratios, f _δ
Bottom structure:
	secondary stiffening primary girders and web frames	475 625
Side structure:
	secondary stiffening primary girders and web frames	475 625
Main/strength deck structures:
	secondary stiffening primary girders and web frames hatch covers	625 775 775
Superstructures/deckhouses stiffeners:
(a) Generally:	secondary primary	400 475
(b) Coachroof:	secondary primary	475 625
(c) House top:	secondary primary	400 400
Lower/inner decks and house top, subject to personnel loading:
	secondary members primary members	475 625
Deep tank stiffeners:
	secondary members primary members	625 775
Watertight bulkhead stiffeners:
	secondary members primary members	400 475
Multi-hull cross-deck stiffeners:
	secondary members primary members	475 625
Vehicle deck stiffeners:
	secondary members primary members	625 775
Helicopter/flight deck stiffeners:
	secondary members primary members	625 775
Note Where significant curvature exists over the span of the stiffener or breadth of the panel, the allowable deflections will be specially considered.