Island Spirit 401 Stress Cracks

[ElCapitan_John]

Does anyone have any experience with stress cracks on the inside of the hulls on Island Spirit cats? We have a cat here that has cracks on the inside wall that run from the portside forward cabin, through the head compartment, to the aft portside cabin. We were told that this was due to substandard materials being used. The inside walls seem to have been made with a kind of bondo plastered over the fiberglass of the hull.

[Southern Star]

No personal experience with Island Spirit cats, but if the inside finish is merely a fairing like 'bondo' over the rough interior glass, then I suggest that you consider the following:

1. Are there any signs of stress cracks on the outer gelcoat in the effected areas?
2. Having removed some significant areas of the bondo, are there any areas on the inside of the hull laminate that shows signs of cracks/crazing?
3. Testing the laminate (free of bondo) in the areas in question by means of a rubber mallet and moisture meter, are there any underlying areas of delamination, voids or water penetration?

If the answer to all of the above is no, then the cracks could simply be the result of the bondo having having been mixed with too much catalyst (making it brittle). But I would be surprised if it was that simple (and still very suspicious if the hull had recently been painted).

Good luck (and welcome to the forum)!

Brad

[Intentional Drifter]

Hi, and welcome to CF.

I, too, have no specific experience with Island Spirits, but you might contact Kent at JustCatamarans. He's on CF, too. I think they know these cats pretty well.

Off hand, I would also be suspicious. Cat hulls do take a lot of flexing and sometimes the interior finishes will show show separations due to the flexing that is nothing to be concerned about, but it can also be serious, too.

That sounds like quite a large one - or at least a long one - and that concerns me much more than a 2" crack along an obvious flex point. A surveyor may very well be in order.

ID

[ElCapitan_John]

Thank you to Intentional Drifter and Southern Star. It is indeed a bondo-type lining.
The hull was not repainted and we don't think the cracks could have been caused by collisions with pilings or docks as they are well above the bump rail. We went in there with a grinder and removed the bondo up to the fiberglass. No evidence of delamination or moisture. It definitely looks like stress caused by flexing, maybe compounded by bad bondo? We are reinforcing the inside of the hull with extra fiberglass and will fill up with good quality bondo. Hopefully that will help.

[sww914]

Rage Gold is good, at least from an automotive POV.
I would be more inclined to use epoxy with Cabosil than body filler if you're already having stress problems.
I've seen 0 failures of Rage in thousands of repairs, but that's on cars, not boats.