On a commercial glass boat with gelcoat?
Or a wood/epoxy boat with a colored hull?

On a Valley sea kayak.

Dynel definitely doesn't wet out clear.

I'm ok with that.

Dynel is more abrasion resistant than glass, but it's so easy to put on multiple layers of glass on a keel strip that it sort of evens out, IMO.

That is my typical line of thinking too, but I wanted to try it this way for fun/to do something different. I'll probably end up going with fg tape, but just wanted to check out other options. I know that the place for abrasion resistance is in the surface layer so it's better to focus on making that hard and don't worry about the fabric as much because by the time you've hit the fabric the abrasion resistance is gone.

BTW, I bought and used Dynel back in the 90s and it was a yellowish soft cloth which really 'fluffed up' with epoxy. The stuff I got a couple of years ago was quite different - a white cloth, not nearly so soft and 'fluffy', but still marketed as a Dynel-type fabric. The newer stuff didn't bulk up so much.
(I read that Dynel thread isn't actually being produced by the original manufacturer any more, so that may explain the difference.)

That's interesting! I'm ordering some even if I don't use it for this project and I want to play with the cord too - which I've never used but looks perfect for some other stuff I want to do.

Some folks use Kevlar for keel and 'bang' strips, but I don't like working with it at all.