> I recently pulled my 1980 Prindle out of mothballs.
> A check of the hulls revealed a 3 inch by 1/16 inch split in the bottom
> of one hull (this was the only place leaking when I filled the hull with
> water) further inspection revealed that both hulls are pretty thin on the
> bottom. How can I economically re-glass the bottom of the hulls. Do I need
> to use resin and cloth or just resin?
So... you've dragged it across the sand for years and now the bottom is
sanded away. Depending on what you expect from your boat and how much you
are willing to spend (time and/or dollars), you have several different
Assuming the rest of the boat is fine, if you want to race your Prindle,
your best bet is to find a good set of hulls and buy them -- someone with
the exact opposite of what you have -- great hulls but no mast, sails, &c.
Any repair work will be heavier than original because of the splice area
between the good part of the hulls and the repair. Also, a good deal of
care and elbow grease needs to go into the fairing of the repair area both
in and of itself and as it blends into the good parts of the hulls.
Use a disk grinder to feather back the edges of the repair to as fine a
taper as you can -- essentially, you're making the damage 'worse' in order
to repair it effectively. The more gradual the taper, the better quality
the repair. Try to determine the weight of the cloth used in the original
construction. Generally, in light foam-cored construction, a fine cloth is
used as opposed to a heavier roving.
Drape the cloth of the repair and cut oversize. I'm guessing three or four
layers is about right. Each successive layer should be slightly larger
than the last so you are left with only one exposed edge.
Epoxy resin will make a better repair than polyester resin, but it costs
more, is harder to use, and takes longer to cure. It makes a better repair
because it sticks to the old material better and is stronger. When you
laminate the resin into the cloth, be sure to completely wet-out the cloth
(completely saturate with resin -- no dry spots) and then squeegee out as
much of the resin as humanly possible. The pros put a vaccuum bag around
the area to REALLY squeeze out the resin.
After the resin has gelled to semi-hard, do some gross t*** around the
repair with a razor knife.
After the resin is completely cured, break out the disk grinder and
feather in the patch. Don't grind away your whole repair though! Finish
with sandpaper glued to long flexible boards (fairing battens) to achieve
an over-all smoothness to the repair. If you find some low spots, fill
with a mixture of epoxy resin and microballoons -- it's light and it sands
easily. This smoothing and fairing is time-consuming and takes a good eye.
The more time spent here translates into a nicer-looking repair.
Finally, paint to suit. May as well paint the entire hulls. LPU will give
the best service for a beach boat. Gel coating the repair is possible, but
even harder to do right than the glass work. Gelcoats needs to be excluded
from air to cure properly so it is usually sprayed with water-based
mold-release after it starts to 'kick'. It changes color slightly upon
curing so a good color match (especially against the faded original
gelcoat) takes skill and experience. After it is entirely cured, the mold
release is washed off and the gelcoat is buffed or wet-sanded smooth.