TOPIC: Removing and replacing badly cracked gelcoat

The gelcoat on my 18' 1960 Span America is very badly cracked from the waterline down. (The cracks are only the gelcoat--no deeper-- and nothing above the waterline is affected.) I'm going to grind/sand the gelcoat off the entire bottom but have a few questions:
1. Any hints on the easiest/best way to turn the boat upside down so it is easier to work on?
2. I've been doing some test sanding using very aggressive disc sanding pads and I've found it is impossible not to cut deeper in some places than others. I've thought about using a belt sander. Any suggestions on the best method?
3. What is the best product to use to fix the imperfections I've created by my inexpert sanding? I saw a reference SATX made in a post about using epoxy mixed with lime but it had no details.
3. What is the best product to use to replace the gelcoat?

I'll suspect you'll see from the nature of my questions that I've never done this type project before, so any help anyone can provide will be greatly appreciated.

If you look under delmar restoration you can see I just had to do the same thing.to flip the boat over I ask for help to push it over by hand and the deck I can do it myself.just be patient on grinding and leave the grinder flat not tilt at an angle.for filler I use polyester base filler after that I just gelcoat cause I personally think it is better for the bottom cause you can put it on thicker then paint and it is harder then paint.

Do NOT use a belt sander unless you are extremely skilled with it and know exactly where the flat spots are on the hull. They can ruin hulls if you over sand - easy to do with those - make curves square or flat, etc.

use less aggressive pads, and do a couple of passes to get past the gel coat. the tutorials and numerous restoration posts on here are awesome. I just started a process by doing trial and error on an old dinghy I am going to fix, so by no means an expert but in my old age I have finally learned that, with this kind of work, going in layers in the end is safer and gives the experience needed to get aggressive later.

I'm still a big fan of the 6" da sander....takes a lot longer but you have a lot more control....john

I removed all the gelcoat off my '61 hydrodyne by hand. I used the orbital sander and it took quite a while, but in the end, it was worth it. West System was what really got me through it all. After sanding it all down...use a cheap painter's suit to keep from getting itch every day...I used West System epoxy resin and fillers to fill and fair. I made sure to use their pumps because they are calibrated with the resin and hardener. So I never got a bad mixture. You can find some pics of my work at hydrodyners.com. One of these days, I hope to put together a detailed pictorial of the process from beginning to end.

Either a R/O sander or a 7" Grinder with 60 grit discs. Since you're going all the way to glass you don't have to worry about being perfect. You can fill any imperfections once all the gelcoat's been removed and you're ready to re-Gelcoat. Don't forget, you can't use epoxy based products if you want to re-gelcoat your hull. If you're going to Paint then epoxy is fine.