∇ is the volume of the moulded displacement of the ship, excluding appendages, in a ship with a metal shell, and is the volume of displacement to the outer surface of the hull in a ship with a shell of any other material, both taken at a moulded draught of d1; and where
d1 is 85% of the least moulded depth.
(b) When calculating the block coefficient of a multi-hull craft, the full breadth (B) as defined in paragraph (4) is to be used and not the breadth of a single hull.
<Chapter I, regulation 3>.
Source: IMO Resolution MSC.143(77), amendments to Annex B to the 1988 Load Lines Protocol, 5 June 2003, International Maritime Organization. Legislation