§171.067. Treatment of stepped and recessed bulkheads in Type I subdivision.
46 C.F.R. § 171.067
For the purpose of this section—
The main transverse watertight bulkhead immediately forward of a stepped bulkhead is referred to as bulkhead 1; and
The main transverse watertight bulkhead immediately aft of the stepped bulkhead is referred to as bulkhead 3.
If a main transverse watertight bulkhead is stepped, it and bulkheads 1 and 3 must meet one of the following conditions:
The separation between bulkheads 1 and 3 must not exceed the following:
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.
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.
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:
Distances A and B must not exceed the maximum spacing allowed by § 171.065.
Distances C and D must not be less than the minimum separation prescribed by § 171.065(e).
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.
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).
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.
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).
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.
Notes, amendments, and revision history
Authority
Authority: 46 U.S.C. 2103, 3306; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; Department of Homeland Security Delegation No. 0170.1.
Source
Source: CGD 79-023, 48 FR 51017, Nov. 4, 1983, unless otherwise noted.