Fibreglass repair on a speed boat hull.

I have just got a 13ft speedboat,but is in need of repair. I have no idea what make of boat is it as where is no name on the boat. I have a big repair to under go on the hull. I am new to this and was wondering if there should be foam between the two skins on the boat. I'm I better taking this foam out and to leave it out? Am I better to fix the hole from the top or the bottom? As I said above I am totally new to this and any advise given would be great.Kindest regards Steve.

 

hello mate, i am in a similar position, except mine is only a minor repair that needs doing.

have a look here, very informative.

 

Hi steve,
does your hull bottom consist of two skins of fibreglass, one bonded to each side of a foam core somewhere between 1/4" to 1" thick? If so, does the foam tend to disintegrate easily, is it wet, or is it pretty solid?
Foam coring is used to make a panel stiffer for its weight. However, in the underside of a boat, foam tends to absorb water and deteriorate. A lot of builders have been known to use really crappy materials as cores, that are totally unrepairable once they begin to fail. If a cored laminate turns out to be repairable, the repair is easiest if done from both sides.
Do you have any pictures you could post?