My experience with Tales showed me that there was no issue with the Formit hull itself. The hull join, where I exposed it, was well executed and the hull thickness was appropriate wherever I witnessed it (through hull fitting holes). I did need to repair a number of blisters over the years but that is pretty common on polyester resin boats from that era. None of the blisters went very deep.
There is a skill in laying up with a chopper gun and I suspect that Formit used the more experienced operators on the hull itself.
The deck, coach house and cockpit were another story and I found variable thickness and voids in these areas which I needed to repair.
The only area of the hull to deck joint I had any problem with was where the bow fitting is bolted on. It is a very difficult place to lay up the tabbing inside so it is common for voids to be found there. Also the fastening if the bow fitting was through a wooden block (glassed in) and any movement of the fitting can allow moisture in along the fasteners. This can rot the wooden block with obvious consequences. Many MkIIs and MkIIIs have been repaired in this area.
So I advise inspection for blisters and repair them (properly, not just with polyester filler) but don’t loose any sleep about the integrity of your hull below the water line.
Cheers,
Tom