Re: Gelcoat Cracking
I think the only way to properly fix this, would be to re-gel coat it. This also depends on the extent of the cracking, but sounds like it's throughout.
I'm envisioning either you patching in the small areas that you chip away with your knife filled with Marine Tex, and then next year when the rest of the gel coat falls off, you'll be left with checkerboard MT all over your hull, and you'll be back asking the best way to get it off.
I'd sand the gel coat down, and re-apply with new. More expensive, but doing it right is less-expensive in the long run.