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, see Table 7.2.1 Limiting deflection ratio. The coefficient equates to a span/deflection ratio, f_δ, in consistent units.

Table 7.2.1 Limiting deflection ratio

Item		Deflection
Item		ratios, f _δ
Bottom structure:
	secondary stiffening primary girders and web frames	800 1000
Side structure:
	secondary stiffening primary girders and web frames	800 1000
Main/strength deck structures:
	secondary stiffening primary girders and web frames hatch covers	1000 1250 1250
Superstructures/deckhouses stiffeners:
(a) Generally	secondary primary	600 750
(b) Coachroof	secondary primary	800 1000
(c) House top	secondary primary	600 600
Lower/inner decks and house top subject to personnel loading:
	secondary members primary members	800 1000
Deep tank structures:
Stiffeners	secondary members primary members	1000 1250
Watertight bulkhead structures:
Stiffeners	secondary members primary members	600 750
Multi-hull cross-deck structures:
Stiffeners	secondary members primary members	800 1000
Vehicle deck structures:
Stiffeners	secondary members primary members	1000 1250
Helicopter/flight decks:
Stiffeners	secondary members primary members	1000 1250
Note Where significant curvature exists over the span of the stiffener or breadth of the panel, the allowable deflections will be specially considered.