by probing with the point of a knife, chisel, or
screwdriver. Press the tip of the instrument against the
Preventing rot or decay requires joint efforts with
wood. If the wood is sound, the point will encounter
the Boatswain's Mates or other personnel who are
increasing resistance as it penetrates deeper. In rotten
charged with painting and caulking the boat. You
wood, the resistance will seem to decrease once the
should inspect boats in your charge fairly often to
paint layer is penetrated. A screwdriver tip will seem
check the following causes of decay:
to pop through the paint and into rotten wood.
Decay may also be found in association with
-- Parts of the boat may be too dry or too wet.
physical damage. Weak planks and timber will be the
Strong sunlight or storage near hot machinery can dry
first to yield to stress. When inspecting collision or
out the wood. Dryness causes wood to shrink and crack.
similar damage, look also for signs of rot.
Water can then seep between planks and into cracks,
wetting interior areas which will not dry before rotting
has started. The microorganisms that cause wood to rot
require a limited range of dampness to be active. Most
of these organisms are fungi, and they will develop in
Emergency repairs to boat planking can be made
wood having over 30 percent moisture content. They
with sheet lead, plywood, canvas, or glass-reinforced
plastic. If the patch is anchored to sound wood, it can
need some air, and they will not develop in wood fully
last several weeks. If an emergency patch just covers
saturated with water, from which comes the term dry
a hole and is fastened to rot-affected wood, it should
rot. Once in wood, they will be dormant if the moisture
be replaced as soon as possible.
content is less than 20 percent, or if the wood is satu-
rated. Fresh water causes more decay than salt water, so
Most emergency repairs to frame members consist
of reinforcing damaged timbers by backing them up
trapped. Boats with closed spaces should have adequate
and shoring them. Backup bracing can be temporarily
ventilators installed or hatches opened up and interiors
nailed or lashed in place. Boats having serious
dried out whenever the weather permits.
structural damage are not seaworthy, and temporary
repairs are made only to get them to a safe place where
-- Cracks and seams are places where decay can
they can be repaired or surveyed.
start. Not only can dampness persist in narrow cracks,
but other agents that cause decay can get in there. Look
for cracks in boards and faulty caulking. If you find any,
notify the boatswain's personnel to correct the problem.
The first step in repairing a damaged boat is to
-- Plain iron fasteners or galvanized fittings that
make a general survey of the situation. Determine as
have lost their zinc coating will favor decay in oak frame
best you can the extent of the damage. Having done
members. Also, water may leak into the hull in the
this, consider whether you have the facilities and
vicinity of these fasteners.
materials to make a repair. If work and storage space
are limited, you might have to defer work on the boat
-- Caustic chemicals, such as those used in clean-
until materials can be obtained. If you have adequate
ing, should not be allowed to stand in contact with
space, it would be best to haul out the boat for a
wood. They can dissolve the wood and weaken it. Acids
detailed inspection and drying out before work is
are less destructive; but strong acids, such as those used
begun. If the boat has been sunk, the Enginemen will
in batteries, will attack wood.
want to take out the engine, transmission, and
-- A common cause of decay is destructive attacks
electrical equipment for drying out and overhauling.
If the hull is not repairable, remove the reusable parts
by marine borers. This and general marine fouling are
prevented by proper bottom paints and occasional over-
and dispose of the hull.
haul. Borers are not a problem for boats kept out of the
As soon as a boat has been hauled out, its bottom
should be cleaned. Barnacles and other marine growth
Decay, particularly rot, will not start in any place
are more easily removed when they are wet. They
where it is easy to detect. It may cause cracks and
smell better then too. After the bottom is cleaned, the
discoloration of paint, but since it is most likely to
boat can be set up in the work area. The hull should be
occur in bilges, behind ribs or frames, or in closed
dried out, the bilges cleaned, and any rotten wood cut
out so adjacent areas can dry out. When the boat has
comers, it will be hard to see. Traditionally, it is found