Hey, thanks!
Some of the "varnishing tips" sites I've read don't ever explain why it's key to sand or steel wool between coats (or say why anyone would want to sand the epoxy first with grits finer than 100 or 150 -- which I suspected was a bit of over-kill.) Glad I asked before I put on my next varnish coat, because the first really does look great.
Regarding the spots I sanded through. I assume I'm okay there?
Often in the building process, it's a challenge to determine how critical certain "tips" we glean from the web really are. This may sound strange, but as a newbie builder and paddler, my aim now is simply to build a functional, passably pretty boat -- I'll save efforts to make one that looks like heirloom quality furniture for when I move up to a striper!
This site is a real asset.
Next up, the Pygmy Triple. Then, a visit to Newfound Woodworks.
Cheers,
Grambo

: sanding to 100 grit before starting the varnishing should be fine. After
: vearnish you'll want finer grits between coats.

: The reason for sanding between coats of varnish is really two-fold..

: 1- it levels the surface to get rid of any sags, runs, drips, etc and to
: remove any dust specks, bugs, whatever on the finish.

: 2- and here's the real reason for sanding. The adhesion between coats of
: varnish is mechanical not chemical. Sanding gives the next coat a
: "tooth" to lock into.

: Lacquers and finishes of that type slightly melt the previous coats, ( in the
: furniture refinishing trade we refer to this as "burning in")
: and actually become one with them, Varnish nor Polyurethane does this. So
: you need to sand to the point where the gloss from the previos coat is
: pretty much gone. As you progress through the coats of varnish of course
: you'll progress to finer and finer grits also. I finish furniture up with
: 320 and 4-0 steel wool unless it is getting rubbed to a finer gloss- then
: I use rottenstone. That's another tale.

: good luck.