Ballast tank leaks.

[MarkDarley]

Has anyone else experienced the ballast tanks leaking where the white rubber sealant is supposed to seal the tank to the hull molding?

My friend Jim who bought the only wooden Bayraider in the US, has this problem and I thought it was because he had a glass ballast tank dropped into his wooden hull.  However my ballast tank in Kelpie, a GRP Bayraider 20, has now sprung a leak at the rear of the ballast tank.

Why is this tank not glasses in?  Are the later boats built with a glassed in tank?
And how has anyone else gone about solving this problem.

As I sail along to windward, I can see my high side ballast water draining into the well and out the bailers....not very helpful!