(1) Except as provided in paragraph (2) of this
Regulation, the length of a superstructure (S) shall be the mean length
of the parts of the superstructure which lie within the length (L).
(2) Where the end bulkhead of an enclosed superstructure
extends in a fair convex curve beyond its intersection with the superstructure
sides, the length of the superstructure may be increased on the basis
of an equivalent plane bulkhead. This increase shall be two-thirds
of the fore and aft extent of the curvature. The maximum curvature
which may be taken into account in determining this increase is one-half
the breadth of the superstructure at the point of intersection of
the curved end of the superstructure with its side.