The Tap Test

I know you can test your hulls for delamination by tapping them with the handle of a screwdriver and listening for a change in the sound as you go from strong to delaminated areas.

My question is: how dramatic is this change? How subtle?

The reason I ask is that I have a '78 H16 that I have just noticed a couple small cracks in the gelcoat. The cracks are about 2" long and I wanted to make sure the hulls weren't delaminating in these areas. However, when I would push against these spots, I can't tell if the hull is actually flexing inward or if I'm just rocking the hull on the trailer! It's not blatently obvious.

Same thing with the "tap test". I'm not noticing much change in tone at all as I tap about my hulls.

Am I worrying about nothing? Would it be obvious if there were delamination going on (either hull flex or obvious change in "tap tone")?

This site has been great at giving me the info on how to fix a hull problem, now I just need to find out if I do, indeed, HAVE a hull problem.

Thanks in advance,
Nick

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1978 H16 "Burt The Cat"

Soft is Soft.

Delamination will feel flexible, if in an area large enough to matter. You will see and feel the surface depress. I think you may be over concerned if you can't really tell.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

That's what I thought, but I wanted to get others' opinions.

I think I'll fix the cracks and just enjoy the sailing season....if Michigan ever thaws out, that is!

Fair winds,
Nick

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1978 H16 "Burt The Cat"

Nick... I had a '79 model that had extensive delamination. There was NO doubt about it. Not only could you feel and hear it, you could actually see the slight ripples in the tops of the hulls. It sailed that way for a long time, but I was always waiting for for the boat to fold up under stress. It was fixable (inject resin), but not without probably adding considerable weight. I just used it as an excuse to buy a new boat!
Good Sailing, Mike