Thanks for the tips, guys.

I'm going to dive down today and applya patch on the patch. The water loss has slowed, but it's still WAY too much to live with. I'm going to use the same stuff: Boxer Adhesives and a piece of the original liner. I'll vacuum and scrub the area (as much as possible) before application, then try to stay underwater longer so that I can get a good seal. Here goes nothing...

K