MD,
I suggest filling in the bottom of the hulls with West and filler to make a paste it is hard. Bondo is a waste of time if you want to keep the boat. If prep is done gelcoat will work. You can use PVA but gelcoat wax additive to the last coat is cheaper and works just as well. Ask your supplier or look at Glue Products or same type of website. Gelcoat can also be brushed and rolled on the bottom it is out of site and can be sanded smooth. The key is to seal the glass.

Painting is great the best. If you have the equipment and knowledge or want to learn the ropes paint. It is hard but rewarding. I just finished painted this boat last weekend. The project included bottom work, fabrication, and fairing work. http://www.themanshed.net/supercat-20.html look at last picture. I need to get the picture part of website working I have a lot of repair type of pics that may help. I hope my webmaster gets that going soon, I just finished his boat....

If a slacker did the work, original epoxy, some people use epoxy when they should add glass. If your friend knows glass and says it is ok - you should be ok. I've seen slacker work, and I've had some of my old glass work popped when I suffered internal damage in the hull and the boat flexed after a nasty capsize. It is not nice to start sinking at sea, been there. Also I do not do any repair work with poly resin anymore.

If you "sail up" when you beach the boat and to just want to get by easy and cheap - tape off the bottom and go to Walmart and buy a spray can. The bottom will not show and it will sand off with each beaching.

Living and sailing on the beach for 30 plus years I've done my share of bottom jobs on cats. It is still thrilling to sail right up on the beach, baby the boat – I’d rather leave it on the trailer.

All of the posts are great, everybody is right it is up to you to decide. Me I'm a bit anal.

I've built boats, worked for several boat builders, built show cars, enjoy doing this type of "hobby", and I have 30 plus year of tinkering. It all started with a NACA 5.2 when they first came out and waxing then the hot cat a hobbie 16 in the mid 1970's. All of a sudden my 5.2 had a hole in it the 3rd race. Next weekend I learned repair work and it is all history after that.

My suggetion is set a few goals. How much money, time, and what level of effort you want to spend on the project. From those decisions you can go from Awl Grip, Gelcoat, Spray, Brush, Paint can from Walmart. I spent over 6 months of my free time on the SuperCat.

Enjoy!