: I'm building a Guillemot for my wife. I want to keep it light so she'll be
: able to lift it atop her Honda CRV. For that reason, I didn't put a second
: layer of glass on the "football". I don't think she's going to
: be paddling in many extreme situations, so I think it'll be all right.

Abrasion from sandy beach launches and landings can eventually take its toll,
but you can always add a keel strip, or a larger patch of glass, as and when
this starts to become a concern. Remember to thoroughly sand off varnish before
doing this sort of maintenance.

: I want to know some strength vs. weight considerations regarding filling the
: weave on the glass on the inside of the boat. It won't show, so I don't
: need to put on extra coats of epoxy to get that shiny, smooth effect.
: However, if I just put on one coat of epoxy when I wet out the glass, will
: that sacrifice any strength?

The strength comes almost entirely from the glass - the epoxy is to hold it
in place. Filling the weave is needed to get a fine finish, but inside the
boat, you probably don't need a fine finish. Indeed, where you fix a seat
and where you put your feet, it is better to have a grippy surface - just
make sure that there are no sticky-out bits of glass fibre which could pierce
a bare foot or leg - you can usually ensure this just by a light sanding. The
real hazard tends to come later from using short cut lengths of fibreglass
tape to secure things like cheek plates - these clean up with a knife or
sanding, but you might want to add a little more epoxy to ensure that ends of fibreglass are definitely encased.

Andy