On closer inspection, there are a lot of bits of hull panel that are soft. I cut out all of the bad and put in new bits it would be a lot of patchwork. I'm worried that if I started cutting big holes in the hull panels that the boat would lose it's shape ???
Another alternative would be to entirely replace all of the hull panels from about 1/3 of the way back from the bow. There is a bulkhead at about 90 inches from the bow, just aft of that there are butt blocks which join the hull panels, I am thinking it might be better to try to remove all of the hull panels from there and start again.