First, I am assuming you mean pool cover, not pool liner (a heavy rubber material.)

Second, I suggest you talk with the manufacturer of the product. You may or may not be able to find an adhesive fix that is permanent.

If it were me, I'd clip it together, mark it, and have someone with sewing skills run it through a sewing machine using nylon thread. Basically, you are doing a simple tailoring project with a piece of fabric.

Sorry for the lateness of my reply. You are right that I am speaking of a pool cover.

I had not thought of sewing one but am still interested in an adhesive to seal and now sewing. I an not sure what chore I will have to take on but my wife has a serger and is quite proficient with it. Thanks for jarring my brain in a different direction. I suspect that an adhesive coupled with sewing would be quite strong. That will be my plan.

And the thought of talking to the manufacturer about the adhesive was simple and perfect. Why didn't I think of that?

Hortus-
Sometimes I also need another perspective when I get too close to a problem. Good luck with the project. And if it is only sewn, I think it will still be quite strong...I have a sewn barbeque cover that has held up outside for the last eight years and been subject to a lot of abuse, and the stitches are still fine.

I am a big believer that any project worth doing is worth doing to excess.

I'm sort of the same way, although I've learned a few times that the perfect can be the enemy of the good! In any case, good luck. Please post an update on how the project worked out.

I will do. Since it has rained a fair bit of late I will start digging the foundation (by hand) over the next couple of weeks. It's always easier to dig wet dirt.