TM 55-07/NAVSEA OP 3221 Rev 2
7-4. End Bulkheads
End bulkheads, which must be in place before the initial unit loads are emplaced within the stow, can be either heat type
or nonheat type. The type depends on the location of the stow with respect to heat-radiating surfaces, such as
engineroom bulkheads.
a. Heat Bulkheads. Heat bulkheads are recognized by tight, unbroken face-boarding constructed at least 1 foot of
f
the ship's permanent bulkhead. The smooth side of the bulkhead must always face the stowage of explosives or
(1) In cases where such heat-radiating bulkheads are smooth on the cargo side (that is, where stiffeners are
on the side opposite the cargo), construction will conform to 46CFR142.29-75. This regulation requires that a minimum
separation of 12 inches be maintained between the boarding of the heat bulkhead and the ship's bulkhead; this
requirement must be considered for all construction. Sheathing is constructed of 2-inch lumber, preferably at least 10
inches in width. Federal regulations require 4by 6-inch uprights spaced not more than 30 inches apart in the tween or
shelter deck or 6by 6-inch uprights spaced not more than 24 inches apart in the lower hold. Shortages of 4by 6-inch and
6by 6-inch lumber, however, are increasingly evident. With special exemption in accordance with 46CFR146.02-25 and
49CFR107, use of the more abundant 4by 4-inch stock may be considered for bulkhead construction. As summarized in
table 5-1, 4by 4-inch uprights will be spaced at intervals not to exceed 24 inches between decks or on the shelter deck
and will not exceed 16 inches in separation in the lower holds. Two-by six-inch lumber will be used as necessary for
headers and bearers. Bearers are optional if wood flooring already covers the metal deck. Uprights are fastened at the
top and bottom to horizontal stringers of suitable size to obtain a 12-inch separation with the ship's bulkhead.
Intermediate stringers should not exceed 5 feet in actual separation from the upper and lower stringers.
(2) When stiffener beams are on the cargo side of the ship's bulkhead, construction details of the heat bulkhead shall
conform to those shown in figure 7-11. Uprights of 2by 4-inch minimum lumber are fitted against the stiffeners in
sufficient amounts to provide the required 12-inch bulkhead separation. Headers are not generally required; bearers
need to be laid only if the metal deck has not been floored over. If the ship's permanent stiffener beams exceed a
center-to-center spacing of 30 inches, dunnage should be built up to match the stiffeners or 2/2-inch boarding should be
used as an alternate method. However, the more common and expedient method is to build up dunnage between
stiffeners, since the 2 2-inch material is not readily available in many areas. The uprights are sheathed with 2-inch
lumber, preferably 2by 10-inch or 2by 12-inch stock, or with /4-inch plywood sheets. As an alternate method of heat-
bulkhead construction, jacks may be used to provide the necessary support for the 2-inch boarding. This type of
bulkhead may be used on either the smooth side or on the stiffener side of the ship's bulkhead, and is shown in figure 7-
12.
7-12
