I guess option C might be adding a few epoxy "patches" only in the spots where I sanded too deep (and using a squeegee to keep them thin) and then sanding lightly, enabling a quick transition to varnishing.  The only thing that makes me nervous about this idea is that I ended up with a few dark runs of epoxy on the hull (presumably due to batch-to-batch mix mismatches in the epoxy/hardener).  I think spots of different colors on the deck would be worse than just leaving it as is.  I've been pretty careful about my ratios since then, though (using a measuring cup since my pumps are not reliably metered at this point), so I think this is unlikely.

Apologies for the essay - brevity in boatbuilding posts is not my strong suit!

First, there's nothing wrong with your epoxying skills, it's the sanding you need to work on. Applying lots of thin coats with a squeegee instead of a couple of thick ones some other way is the best way to avoid runs, drips, excess weight and wasting epoxy. Don't change what worked. Work on what didn't.

Next, if you want to see what a glassed, epoxied and sanded surface will look like after varnishing, wipe it with a rag soaked in denatured alcohol. Whatever it looks like before the alcohol evaporates is what it will look like when it's varnished.

As to what to do:

1. If the alcohol test shows no visible glass, you're fine. You haven't really sanded into the glass. What you have is an optical illusion caused by a very very thin layer of epoxy over saturated glass. Proceed to varnish.

2. If the alcohol test shows whitish weave then you got into the glass. Cosmetically, that is what it will look like under the varnish, no matter what you do with additional epoxy layers. You are never going to be able to eliminate that without removing and replacing the abraded glass. You need to decide if you're willing to live with that or if you need to do some reconstructive work. Structurally it's sound and just needs a sealing layer of epoxy.

What I did with my boats when that happened is basically your option C - spot repairs with a thin layer of epoxy. A disposable foam brush is perfect for that. Then once it cures, be very very careful with the sanding. You may want to grab some scraps of wood and glass and make some corners to practice your sanding on. Keep monitoring your progress with alcohol tests.

The good news is that as long as you didn't sand through to the wood your boat's function and strength will be unaffected. This is all a purely cosmetic issue.

Good luck,

Laszlo

Laszlo,

Thanks very much.  I can't see the weave once I've put denatured alcohol on it (even under sunlight), so I'll stop sanding/coating the deck (phew!).

The only thing between me and varnishing/painting at this point is sanding down the border between the deck glass that I extended about 2" onto the hull (and the rest of the hull).  I didn't feather it enough initially and ended up with a really nasty transition (cliff, you might say) on those edges that was made worse by the fact that I added epoxy mostly to the tape (and not to the rest of the hull below).  I'm most of the way through sanding the epoxy back down into the tape (and maybe doing one last fill and light sand) to even thins out.  I'm sure it's stronger this way, but I'm kind of wishing I'd just trimmed the deck glass at the deck/hull intersection since it's been so much work (for me, at least) to clean it up.

Glad to have helped head off a lot of useless sanding. As for your other problem, you are so much better off with the 2" overlap. Without it you would be chancing a leak right where you have a seam and two exposed edge grains. As it is, the seam is sealed and the deck glass is protected against peeling off.

Laszlo

Yeah - I'm very glad to not have to go through the tedium of sanding the deck again - believe me!

I think I'll stop sweating small surface imperfections where the deck cloth overlap meets the hull.  On my latest (3rd) lengthy attempt at sanding the cloth edge (or at least the epoxy on top of it) down to feather into the hull, I sanded until the whole surface (across the glass cloth edge and rest of the hull) turned a uniform dull gray, so it's very nearly flat.  I can see the transition due to a small thickness difference in places (with denatured alcohol on top), but only if the light hits it just right, and in the real world the sunlight will hit the hull just right (to bounce back to the eye) approximately never.  Anyway...that's a purely subtractive process, so it's not that big a deal either way.  Maybe I'll have more patience in 12 days when I return to it.

Thanks again.  I added the bottom fillet (and another layer of epoxy) to the coaming today.  2-3 more hours of sanding the coaming and bits of the deck and hatch rim, and I will have emerged from my arduous journey through the Valley of Sand.