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 TB 55-1900-201-45/1
(8)
Areas under refrigerators or other machinery which may drip fresh water.
(9)
In the area of butt blocks and longitudinal members where dirt and debris may have retained fresh water.
(10) At the heads of frames caused by fresh water leakage through defective covering boards.
(11) Where the futtocks of sawn frames join and at the faying surface where the frame abutts the hull plank-
ing.
(12) At the terminal ends of frames, floors, engine foundations, etc., where end grain is present.
d. Under freezing temperature conditions, wood structural members with a high moisture content, particularly in
the bilge areas, may appear quite sound when in fact, they may be in advanced stages of decay. Periodic examination
of these areas should be conducted before freezing sets in, or after allowing sufficient time for thawing.
e. The other principal form of deterioration which goes on within the wood is marine borer attack. Marine borers
can attack any wood which is beneath the water. No species of wood is immune to attack and no method of protection of
the wood is completely effective. Borers can enter the wood through hairline breaks in sheathing (either copper or fiber-
glass) or through scrapes, nicks or tool marks in protective bottom paints. If borer infestation is suspected, a spot check
of the wood beneath the sheathing should be made.
f. A probe is the most effective tool to use in the detection of borers. Avoid over zealous probing since each
probe hole is a potential site of borer entry. After probing is complete, the resulting holes shall be filled with a patching
compound.
g. Marine Borers die when removed from the water for any period of time. A vessel which has been out of the
water for a few days and is essentially dry will probable have no live borers.
h. Where borers attack is just starting it is possible to burn the holes clean with a torch and then fill them with a
suitable compound. If the attack is extensive, the only acceptable method is to replace the affected wood.
i. Keel shoes, rubbing strakes and similar members whose protective coatings have been broken shall be in-
spected carefully. If they have heavy borer infestation, they shall be replaced. Care shall be taken to see that the infes-
tation has not progressed from them to the main part of the hull structure. Though worn shoes are usually separated
from the hull by creosote impregnated felt or by copper sheathing, this separation is usually not 100% effective.
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