From DIY Boat Owner Magazine
That Sinking Feeling
By Nick Bailey
At some stage, most boats will develop a leak. The difference between the
intrusion of a little rainwater and the inexorable progress of a leak below the
waterline is the difference between a boat that floats and one that doesn’t.
Here we look at leaks below the waterline and how to find and fix them
lthough there are rare
examples of the coveted
dusty bilge, most owners
expect to do a little dewatering on their boat occasionally. However, leaks
from above and leaks from
below are not created equal. Discounting
rainwater leaks, some boats are tighter than
others and it’s important to know what the
normal bilge water accumulation is for your
boat. Mental calculations may be required
to assess the “normal” state.
Here’s a good example. The stuffing
box drips every 15 seconds, yielding . 12
fluid ounces in 15 minutes and translating
to about one quart every three days or so.
Not a big deal. If you know what’s normal
for your boat, you should be able to judge
when a leak is getting worse. A bilge pump
counter (available at West Marine) is an
excellent investment that can be wired
into the bilge pump circuit to alert you
to potential leaks that might otherwise go
unnoticed. Just beware of the faulty logic
that a leak ignored will eventually stop.
Finding The Leak To Nowhere
Often, finding the leak is more time
consuming and difficult than fixing it. This
is why many repair facilities often suggest: “You find it, we’ll fix it.” That can be
Easy-to-find leaks occur at hull fit-
tings. Tools required to find these leaks are
simple: a roll of paper towels, flashlight,
and small mirror. Check the inside skin of
the hull by hand for wetness trickling down
from any thru-hull, rudder port (often visu-
ally inaccessible), the shaft log, stuffing
box, and strut fasteners. Other culprits are
trim tab and swim-platform mountings. If
it feels wet, move in for a closer inspection.
Use the paper towel to dry off the hull and
the fitting, and inspect closely using the
flashlight. Look for the first appearance
of a trickle or drip. Dry it again and verify
you are seeing the first point of emergence.
Use the mirror to check the backside of
the fitting. On a thru-hull, for example,
it’s important to determine if the bedding
compound sealing the thru-hull is leaking,
or if it’s an attached valve or hose.
Tools of the trade: flashlight, paper towel,
Leaks at skin fittings are comparatively
easy to find.
Use a paper towel to thoroughly dry the
fitting and surroundings.