Buy a different hull and transfer everything into it... that would probably be cheaper and better.
Or better yet.... buy a superjet. bwuahahahahahahahahah
Id like to be able to fill in the nicks in the bottom of the hull the right way.
I choose $50 in materials over $400 for a satisfactory hull any day!
$400???? Are you kidding me? Please let me know where I can sell $400 750 hulls because I'll be a rich man. I can't even give those things away. I've chopped up more of them than I can count. The paperwork on those is worth more than the hull.
And if you use quality epoxy its gonna cost you more than $50.
epoxy resin with US phenolic microbaloons composites filler, it will need to be roughed up with at least 80 grit paper before you put anything on it, personally I would go 40 grit, coat the whole thing, you can mix it a little soupy and apply it with a paintbrush if you like.
I agree with WFO. rough the entire bottom with 40 grit then use carbosil/epoxy for filling the large chunks/gashes, then sand the carbosil smooth and coat the entire bottom with microballons/epoxy. You can add color pigments to the epoxy/microballons if you like and the trick will be getting the right portions of epoxy and micro ballons, you want it thick enough that it wont run, but thin enough that it will still settle to a smooth finish