(a) Each OSV that is authorized to carry more than 240 persons must comply with the following provisions of SOLAS, 1974, as amended, as though the OSV is a passenger ship and the offshore workers are considered as passengers: chapter II-1, parts B-1, B-2, and B-4, and regulation II-1/35-1 (incorporated by reference, see § 125.180).

(b) Each OSV that is authorized to carry less than 240 persons must comply with the provisions of chapter II-1 of SOLAS, 1974, as amended:

(1) Part B-1 and regulation II-1/35-1 of SOLAS, 1974, as amended, as though the OSV is a passenger ship and the offshore workers are considered as passengers, except that—

(i) The required subdivision index used must be the R value calculated according to regulation II-1/6.2.3 of SOLAS, 1974, as amended, multiplied by the factor F, where:

F = (N + 720)/960 N = total number of persons authorized; and

(ii) Compliance with regulations II-1/8 and II-1/8-1 of SOLAS, 1974, as amended, is not required.

(2) Parts B-2 and B-4 as though the OSV is a cargo ship and the offshore workers are considered as crew, except that regulations II-1/9, II-1/13, II-1/19, II-1/20, and II-1/21 of SOLAS, 1974, as amended, must be applied as though the OSV is a passenger ship.