Jim
I have the exact same problem with my Island on both rear seat plugs. Plugging in the seat also widens the crack.
and below is pic of twist tie poked thru crack.
The lighting makes it hard to see but they are there. Put a light into the hull under set plugs and they really show up.
Matt had this to say about the Island:"We have seen some thin seat plug holes.
If you think about how the boat is formed... this is a raised area in the mold. The plastic has to flow up and over the seat hump and the plug holes protrude from that even higher, so it is an area that could be thinner.
There should be no question about warranty coverage on it. I know that roadrunner has done some coating of knob bolt columns inside his hull with a glue material with great success. This may be an excellent material to seal these... at least as a temporary repair so you can use the boat."
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My dealer has offered to heat weld my hull under warranty. Hobie has also OK'd a self-repair.
Take a 3/4" PVC endcap and fill it with clear Silicone 2 caulking and place it over the seat plug from inside the hull with the hull inverted (so gravity holds cap in place while it dries). Worked fine for me.
Using DP8010 3M Scotchweld & a PVC cap would even be better. Which I plan to use on my 2nd Island before it's seat plugs also cracks, also if the silicone2 fails on cracked hull.
This fix might even be a good idea to do for all Hobie owners of some hull types before a crack develops. Should be a cheap & easy fix. Kinda like drive well shoe and glue fix/reinforcement kit that Hobie offers for the older Outback.
Yakaholic