TM 55-07/NAVSEA OP 3221 Rev 2
c. Cargo stowed in the square of the hatch can betommed as shown in figure 7-33. The hatch cover must then be
locked in place to provide the overhead support for the tomming structure.
7-10. Stepping Down a Load
a. In some cases, particularly in the upper tween decks whe vessel loading is near completion, it may be
necessary to fill the hatch completely, because of the lack of sufficient cargo. This action will reduce the number of tiers
or layers of cargo as the stow progresses toward the center of the compartment. This technique is generally known as
b. Normally, the stowing process will proceed simultaneously from the fore and aft bulkheads and the wings
toward the center of the hatch. If the stepping-down procedure is to be employed, a securing structure that is similar in
construction to a partition bulkhead is erected by positioning 4by 4-inch uprights against the tiered unit loads near each
end and lacing these ends with 2by 3-inch or wider material. The unit load is then placed against the uprights, and the
stow proceeds to completion in this manner. The central areas are loaded last, with remaining smaller or irregularly
shaped unit loads. Full-block securing is used to shore any void remaining in the stow. Based on the volume or weight
of the cargo in the multiple tiers or layers behind the step-down structure, the structure may need to be braced with
diagonal members for added support.
Figure 7-33. Construction details for tomming in square of hatch.