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 TM 55-1905-223-SDC
arranged as to distribute the load over a large area or to carry it to some point of local strength, such as
bulkhead overhead. The same procedure should be followed in shoring one bulkhead to another.
In common with other features of damage control, the possible necessity for shoring bulkheads
must be recognized, and general provision for accomplishing this operation must be made beforehand. The
actual operation should, however, be governed by conditions which exist when and if shoring is found
necessary.
It should be noted that all effective members, except those used to distribute pressure over wide areas,
are direct compression members. The material at hand, assumed to be wood, should be arranged so that the
length of direct compression members is not more than 30 times the minimum thickness or diameter and
preferably not more than 15 times. Thus a 4" x 4" timber could be 10 feet long, but, were it only 5 feet long it
could take a 50 percent greater load.
For shoring, which is a temporary emergency expedient, materials may be stressed almost to the
breaking point. Having determined the necessity for shoring, and the type and arrangement, the extent of
shoring is largely a question of trial and error; in other words, add more shores until the bulkhead is held
securely.
Although the discussion above refers particularly to shoring bulkheads, it applies also to shoring decks.
Section IV.
MATERIALS FOR SHORING
7-4. SHORING MATERIALS. The basic materials required are shores, wedges, holes, and strong backs.
A shore is a portable beam. A wedge is a block which is triangular on the sides and rectangular on the butt
end. A shole is a flat block which can be placed under the end of a shore to distribute the pressure. A strong
back is a bar or beam of wood or metal, often shorter than a shore, which is used to distribute pressure or to
serve as an anchor for a patch. Lumber to be used for shoring is stored in the bow thruster tunnel dam- age
control lumber rack.
7-5. TOOLS AND EQUIPMENT. Many items of tools and equipment are used when shoring. These
include wooden battens, claw hammers, mauls and sledges, hand- saws, mattresses and pillows, axes and
hatchets, wood clamps, chain falls, electric welding machines, oxyacetylene cutting outfits, cold chisels, wood
chisels, nails, wooden plugs, packing sheets, turnbuckles, screw jacks, hydraulic jacks, bolts, nuts, and
washers.
7-6. PROPER WOOD FOR SHORING. The best woods available for shores are Douglas fir and yellow
pine. Hemlock and Spruce can be used, but they are not as strong. The wood used for shores should be
straight grained and relatively free from knots and cracks. Shores could be treated with a fire-resisting
chemical and should never be painted.
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