where
d = internal diameter of the bilge main pipe; mm (in.)
L = scantling length of vessel, as defined in 3-1-1/3.1; m (ft); see also 4-6-4/5.5.1(b)
B = breadth of vessel, as defined in 3-1-1/5; m (ft)
D = depth to bulkhead or freeboard deck, as defined in 3-1-1/7.1; m (ft); see also 4-6-4/5.5.1(e).