CFR > Title 46 - Shipping > CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY > SUBCHAPTER S—SUBDIVISION AND STABILITY (parts 170 to 174) > PART 171—SPECIAL RULES PERTAINING TO VESSELS CARRYING PASSENGERS > SUBPART C—Large Vessels (§171.045 to §171.082) > 171.067—Treatment of stepped and recessed bulkheads in Type I subdivision.

171.067—Treatment of stepped and recessed bulkheads in Type I subdivision.

(a) For the purpose of this section—
(1) The main transverse watertight bulkhead immediately forward of a stepped bulkhead is referred to as bulkhead 1; and
(2) The main transverse watertight bulkhead immediately aft of the stepped bulkhead is referred to as bulkhead 3.
(b) If a main transverse watertight bulkhead is stepped, it and bulkheads 1 and 3 must meet one of the following conditions:
(1) The separation between bulkheads 1 and 3 must not exceed the following:
(i) If the factor of subdivision (FS) determined from § 171.065 (a) or (b) is greater than 0.9, the distance between bulkheads 1 and 3 must not exceed the maximum separation calculated to demonstrate compliance with § 171.065.
(ii) If the factor of subdivision is 0.9 or less, the distance between bulkheads 1 and 3 must not exceed 90% of the floodable length or twice the maximum bulkhead separation calculated to demonstrate compliance with § 171.065, whichever is smaller.
(2) Additional watertight bulkheads must be located as shown in Figure 171.067(a) so that distances A, B, C, and D, illustrated in Figure 171.067(a), satisfy the following:
(i) Distances A and B must not exceed the maximum spacing allowed by § 171.065.
(ii) Distances C and D must not be less than the minimum separation prescribed by § 171.065(e).
(3) The distance A, illustrated in Figure 171.067(b), must not exceed the maximum length determined in § 171.065 corresponding to a margin line taken 3 inches (7.6 cm) below the step.
(c) A main transverse bulkhead may not be recessed unless all parts of the recess are inboard from the shell of the vessel a distance A as illustrated in Figure 171.067(c).
(d) Any part of a recess that lies outside the limits defined in paragraph (c) of this section must be treated as a step in accordance with paragraph (b) of this section.
(e) The distance between a main transverse watertight bulkhead and the transverse plane passing through the nearest portion of a recessed bulkhead must be greater than the minimum separation specified by § 171.065(e).
(f) If a main transverse bulkhead is stepped or recessed, equivalent plane bulkheads must be used in the calculations required to demonstrate compliance with § 171.065.

Code of Federal Regulations

Code of Federal Regulations 117
[Please see PDF for image: EC01MR91.022 ]

Code of Federal Regulations

Code of Federal Regulations 118
[Please see PDF for image: EC01MR91.023 ]