GL: Bottom Paint

[Bob Kunath]

For Greg's question on bottom paint.

Our boat is in fresh water, Lake Michigan where temperature is usually 70 or
less.

Any boat tied up for a week or so starts to grow green algae on the hull.
Left untended, that algae can grow into the fiberglass and becomes very
difficult if not impossible to remove.  A good bottom paint retards algae
growth, and makes it easy to remove.

Barrier coats are something else.  All bare fiberglass absorbs water.
Sometimes that water gets behind the gel coat (reverse osmosis) and into the
roving, where it can cause blisters in the gel coat.  If that happens, and it
is common in boats stored in-water without a barrier coats, repairs are
extremely costly, 10 or 20 times the $1400 you were quoted to apply barrier
and bottom paint.

A few coats of a good barrier, like Interprotect 2000E will protect the boat
from blistering for it's life.  You can do the job, but the hull has to be
dewaxed and sanded first to promote adhesion.

A good ablative bottom paint will protect the boat from algae for several
years if a few coats are applied correctly.

As for your particular area, I would suggest looking at boats stored in water
in your area.  I would be surprised if you find many without bottom paint.
But if you do, compare those to boats painted.  Current will help avoid algae,
but not reverse osmosis.

Bob

Bob & Carol Kunath
Sans Souci
Pacific Seacraft 38T
bobkunath@att.net
Tel: 847 540 8175
cell: 847 921 8175