That would be keel not kewl.

I can't fathom why you'd want to leave tape underneath a reinforcing fabric and/or epoxy laid down to further your build.

My take is: the instruction tells you to trim just along the edge of masking tape, cutting through (in your case) the Dynel cloth that's overlapping onto the tape you put down to prevent its bonding to areas outside where you want it.

Taping off a work area is a common practice. No tape should be left under whatever's applied to that work area. Cutting along the tape edge keeps the stuff you want where you want it while separating it from the stuff you'll be removing along with the tape underneath.

   Thanks for your response. With a new blade in the box cutter I made short work cutting through the dynel and was able to remove all the tape below. It's looking good!