(a) A vessel of more than 19.8 meters (65 feet) in length must have a collision bulkhead.

(b) A vessel of not more than 19.8 meters (65 feet) in length must have a collision bulkhead if it:

(1) Carries more than 49 passengers;

(2) Operates on exposed waters;

(3) Is of more than 12.2 meters (40 feet) in length and operates on partially protected waters; or

(4) Is constructed of wood on or after March 11, 2001, and operates in cold water.

(c) A double-ended ferry required to have a collision bulkhead must have a collision bulkhead at each end of the vessel.

(a) Except as provided in paragraph (c) of this section, each vessel must comply with the Type II subdivision and damage stability requirements of §§ 171.070 through 171.073 and 171.080 of this chapter if it meets one or more of the following criteria:

(1) Is more than 19.8 meters (65 feet) in length;

(2) Carries more than 49 passengers;

(3) Is constructed of wood on or after March 11, 2001, and operates in cold water; or

(4) Is constructed before January 1, 2009 and carries more than 12 passengers on an international voyage.

(b) Vessels constructed on or after January 1, 2009 and carrying more than 12 passengers on an international voyage must comply with the applicable requirements of IMO Res. MSC.216(82) (incorporated by reference, see § 179.15) unless permitted otherwise.

(c) As an alternative to complying with the Type II subdivision and damage stability requirements of §§ 171.070 through 171.073 and 171.080 of this chapter, a monohull vessel which undergoes a simplified stability proof test in accordance with § 178.330 of this chapter may comply with § 179.220 of this part.

(d) For the purpose of demonstrating compliance with the Type II subdivision and damage stability requirements of §§ 171.070 through 171.073 and 171.080 of this chapter, the requirements of IMO Res. MSC.216(82) may be considered equivalent.

[USCG-2007-0030, 75 FR 78091, Dec. 14, 2010]

(a) The maximum distance between adjacent main transverse watertight bulkheads on a vessel, required by § 179.212(a) of this part to comply with this section, must not be more than the smaller of the following:

(1) One third of the length of the bulkhead deck; or

(2) The distance given by the following equation:

$$ where: d = the maximum length of the bulkhead deck in meters (feet) between adjacent main transverse watertight bulkheads; F = the floodable length factor from Table 179.220(a); f = the effective freeboard in meters (feet) calculated for each pair of adjacent bulkheads in accordance with paragraph (b) of this section; L = Length Over Deck in meters (feet) measured over the bulkhead deck; and D = the depth in meters (feet), measured amidships at a point one-quarter of the maximum beam out from the centerline, from the inside of the bottom planking or plating to the level of the top of the bulkhead deck at side as shown in Figure 179.220(a).

(b) The effective freeboard for each compartment is calculated by the following equation:

f = (a + b)/2 where: f = the effective freeboard in meters (feet). a = the freeboard in meters (feet) measured: (1) At the forward main transverse watertight bulkhead; and (2) From the deepest waterline to: (i) The top of the bulkhead deck on a flush deck vessel; or (ii) If a vessel has a stepped bulkhead deck, the line shown in Figure 179.220(b); or (iii) If a vessel has an opening port light below the bulkhead deck, the line shown in Figure 179.220(c). b = the freeboard in meters (feet) measured: (1) At the aft main transverse watertight bulkhead; and (2) From the deepest waterline to: (i) The top of the bulkhead deck on a flush deck vessel; or (ii) If a vessel has a stepped bulkhead deck, the line shown in Figure 1 to § 179.220(b); or (iii) if a vessel has an opening port light below the bulkhead deck, the line shown in Figure 2 to § 179.220(b).

(c) Calculations needed to demonstrate compliance with paragraphs (a) and (b) of this section must be submitted to, and approved by, the Commanding Officer, Marine Safety Center.

[CGD 85-080, 61 FR 971, Jan. 10, 1996; 61 FR 20557, May 7, 1996, as amended by USCG-2007-0030, 75 FR 78092, Dec. 14, 2010]

(a) Foam may only be installed as flotation material on a vessel when approved by the cognizant OCMI.

(b) If foam is installed as flotation material on a vessel, the owner shall ensure that the following tests are conducted and requirements are met, to the satisfaction of the cognizant OCMI:

(1) All foam must comply with NPFC MIL-P-21929C (incorporated by reference, see 46 CFR 175.600). The fire resistance test is not required.

(2) Foam may be installed only in void spaces that are free of ignition sources, unless the foam complies with the requirements of 33 CFR 183.114;

(3) Foam may be installed adjacent to fuel tanks only if the boundary between the tank and the space has double continuous fillet welds;

(4) The structure enclosing the foam must be strong enough to accommodate the buoyancy of the foam;

(5) Piping and cables must not pass through foamed spaces unless they are within piping and cable ways accessible from both ends;

(6) Blocked foam must:

(i) Be used in each area that may be exposed to water; and

(ii) Have a protective cover, approved by the cognizant OCMI, to protect it from damage;

(7) A water submergence test must be conducted on the foam for a period of at least 7 days to demonstrate to the satisfaction of the cognizant OCMI that the foam has adequate strength to withstand a hydrostatic head equivalent to that which would be imposed if the vessel were submerged to its bulkhead deck;

(8) The effective buoyancy of the foam must be determined at the end of the submergence test required by paragraph (b)(7) of this section. The effective buoyancy or 881 kilograms per cubic meter (55 pounds per cubic foot), whichever is less, must be used in determining the location of watertight bulkheads for subdivision required by § 179.212; and

(9) The owner or operator must obtain sample foam specimens during installation of the foam and determine the density of the installed foam.

[CGD 85-080, 61 FR 971, Jan. 10, 1996, as amended at 62 FR 51357, Sept. 30, 1997; USCG-2003-16630, 73 FR 65206, Oct. 31, 2008]