ch situations
are completely destroyed and the boat is rendered worthless before one
realizes that teredos have attacked the boat at all.

But even without marine growths and teredos the planks and timbers of a
boat may become rotten and useless through the action of the water. This
is particularly the case where a boat rests upon a muddy bottom at low
tide, for the mud contains gases and chemicals which destroy the paint
and this allows the water to penetrate and rot the wood.

To guard against these three principal dangers every boat should be
hauled out at frequent intervals, the bottom should be scrubbed, scraped
and cleaned, and should then be allowed to dry thoroughly, after which
it should be freshly painted with some reliable and good anti-fouling
bottom paint such as the various copper paints. Large boats are usually
sheathed or covered with copper plates below the water line in order to
protect the wood, but small boats depend upon a coating of copper paint.

Whenever a boat is hauled out to be scraped and painted it should be
examined carefully for rot or worms and the various planks, the keel,
stem, sternpost, centerboard, centerboard trunk and case and in fact,
all the woodwork below water should be tested for teredos or rot by
probing with the tip of a knife blade. If the wood is sound the blade
will not penetrate readily, whereas if the wood has been injured by
worms or is rotten the blade will enter very easily. When this occurs a
thorough investigation should be made to determine the extent of the
damage.

If the spot is small it may be dug out by a chisel or gouge and the
cavity may be filled with white lead or marine glue and painted over,
whereas if there is a large area damaged a new plank or a new piece of
timber must be fitted. In any case every hole, crack or crevice should
be carefully plugged with white lead or marine glue before painting, for
if this is not done rot and worms will be almost certain to find the
unprotected spots and will commence to destroy the wood.

If there is a strea