GRP Enterprise Dinghy Floor and Tanks

I'm new to sailing and I've just purchase an old GRP dinghy (sails have 1972 on them and number is 165**.) I have some questions and was wondering if anyone could help me out?

Glass enterprises of that era tend to make sieves look watertight.
The floor tank join is a notorious failure point, doubtless the silicon is a previous attempted cure.
I fear I haven't come across a cost effective permanent fix.if you really clean up the join area and put on two layers of glass tape, one wide, one narrow, right across the seam with luck it will make it a lot better for a while.

Edited by JimC - 23 May 16 at 10:41pm

Another weak spot on some old fibreglass ents is the join between the front storage compartment walls and the underside of the foredeck. This doesn't become evident until you have a complete capsize, at which point it becomes a disaster. The solution is the same as Jim mentioned for the side tanks. Bit more fiddly though due to tricky access

Edited by transient - 24 May 16 at 1:05am

A flexible sealant won't work I'm afraid. The problem with side tank joins is that we walk and jump around on the floor, which bends and distorts under foot, especially on a glass boat where the floor isn't that rigid. But because the tank side is pretty rigid (being vertically aligned) the joint is continually opening up.

To be brutally honest I'd counsel not to worry about long term life. The 70s glass Enterprises really aren't built well enough to worry. Get some life out of it for your money, and when it gets too much hassle skip it. Rupert may well have a very good suggestion with duct tape, at least assuming you are sailing inland with safety cover. Slow the water ingress so the sailing experience is reasonable and you'll be OK.
On the other hand if you are sailing on the sea, or without decent safety cover, well, all I can say is that I would not use an old glass Enterprise in those circumstances.

Or lots or plastic 2l lemonade or cider bottles, just to endure you don't sink!