hull to deck and inner liner

[BUNKER]

I recently inspected a 20' I/O where the hull to deck joint was seperated from midships to the transom on both sides. it appears the inner liner would need to be removed to properly repair. has anyone removed their inner liner and just how difficult is this? this boat is very rough, but just might be the project i am looking for.
additionally the fuel tank is located below the forward seat of the console, i was under the impression the tank was below deck. is this tank installation normal or aftermarket ?
appriciate your feedback

Bunker