Formed parts of a boat that have been damaged
lap for mechanical fastenings. The unit can then be
must not be re-formed using heat. When possible, it is
bolted to the aluminum hull with insulation between
suggested that the damaged part be replaced by new
them. Splices can be made across the structural mem-
material formed for the job.
bers. If tapes or neoprene are not available for insulating
Distorted plates, whether caused by damage or the
the steel and the aluminum, material such as Butyl
heat of welding, must not be straightened by flame-
rubber, polysulfide, or any heavy-bodied flexible coat-
quenching (torch heating followed by spray cooling).
ing will do. Avoid wicking materials, such as flax or
The method does not work well and can result in over-
canvas, and the use of lead-pigmented compounds, such
heating or melting as previously described. If the dis-
as red lead. The steel temporary repair should be re-
tortion does nothing more harmful than detract from
placed with the proper aluminum repair as soon as
appearance, it should be left alone. Otherwise, distorted
possible.
shapes should be straightened cold, using jacks as nec-
STEEL BOAT REPAIR
essary, while distortion in plate panels may be relieved
either cold or by making a saw cut in the center of the
Permanent repairs of steel boats must be
panel and rewelding it. When you weld a saw cut, ensure
accomplished by qualified welders and nondestructive
that the correct alloy is used. Cracking of the weld will
test personnel. Fabrication, welding, and inspections
result if the alloy of the filler metal or authorized alter-
must be accomplished as required by the BoatAlt or
nate is not used. The normal shrinkage associated with
applicable alteration or repair drawing. NAVSEA
aluminum welding will tend to remove the distortion.
0900-060-4010 and NSTM, chapter 074 (9920),
The light weight of aluminum will facilitate repair
should be used as guides.
by making handling easier. In addition, the preparation
of subassemblies or repair sections in the shop is greatly
facilitated.
UTILITY BOATS
If welding is impractical or impossible, use bolted
aluminum alloy patches. For this type of repair, the
In the following sections, the discussion will deal
following is needed: an electric circular saw for cutting
primarily with typical repairs made to utility boats.
plate to size and for fairing out any jagged edges in the
When a boat is damaged, the HT is responsible for
hull penetration, and a good metal-cutting saw blade.
making the required repairs. As an HT, you must know
After the patch plate is cut to size, connect it to the hull
the procedures for renewing a stem, stem frame, and
with aluminum or stainless steel bolts or other fasteners.
engine foundation in a small boat.
In an emergency, any type of bolt will do. However, this
In general, the procedures described for repairing
must be considered a temporary repair since dissimilar
utility boats are similar to those required for repairing
metals cause galvanic corrosion. For bolting the patch
motor boats, motor whale boats, and ships' boats for
to the hull, insert a sealing material around the perime-
other types.
ter. If a number of repairs of this type are anticipated,
then it might be wise to provide several rolls of the
CHOCKING THE BOAT
sealing tapes used by aluminum small boat manufactur-
ers. Most major tape manufacturers supply these tapes
Before beginning to work on a boat, you must get
in various thicknesses and widths. These are the tapes
it into a safe position, retain its true form, and prevent
used on modem day aluminum small boats and they do
further damage, Figure 4-25 shows a type of boat
a good job, not only in sealing the seam, but also in
chock that you can construct aboard ship. It is simply
keeping the rivets and bolts from leaking. The holes for
a framework made from 4 by 4's and braced with 2 by
the rivets or bolts will, of course, be made by a rotary
6 lumber. The number of chocks and other bracing
drill.
should be determined so that the craft can be held
If the boat incurs damage in a remote area where
reasonably rigid to a fixed position.
there are no facilities for welding, and aluminum is not
available, temporary repairs can be made with steel
NOTE: When positioning chocks, ensure that they
patches. Some type of insulation, such as neoprene,
bear on the hull at structurally reinforced areas.
should be used between the aluminum and steel, if
possible. Large, temporary hull repairs can be made in
REMOVING DAMAGED PARTS
this manner. The damaged area can be cropped out. The
steel repair plate, including structural framing mem-
Remove damaged parts carefully since you will
bers, can be prefabricated by welding, leaving sufficient
probably have to use them as patterns in making the new
4-22