OK you will get a range of replies. Do you want quick and dirty or back to factory new? What is boat used for, how long on water? How mission critical? Does it have residual buoyancy? Would be things to think about on how quick and dirty to go.
Personally I'd want to open that up and drill holes at ends of the cracks so it doesn't run any further.
Then I'd take the gel beck to good fibre on both in and outside.
Then a patch of CSM (chopped strand mat) with resin on the inside with probably 5cm overlap. Possible 2 or 3 layers depending on where it is, flex etc. Then on water side file the hole with some fibres in resin.
Then gel and apply acetate to smooth finish seal edges.
Remove when set. Sand. Polish buff.
Then flow coat the inside.