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Stress cracks

Billyho

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Is it normal for stress cracks in our rigs? I am the owner of my pops 1989 21 RC Vdrive and just curious if this is normal wear and tear
 

Outdrive1

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Around the windshield dash area?


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Billyho

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I don’t have a wind deflector yet. Only on the top area of the bow and towards the helm.
 

jstnoc

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Typical at the first bulk under deck especially the older hulls. The older hulls did not have pads on top of the bulks.


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spectras only

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They are spider cracks in the gelcoat. nut sructural. I had them on my 72 Spectra, had to grind them out and re-paint the entire upper deck. Gelcoat gets brittle and any flex in the area causing spider cracks, especially for boats in Sun drenched locations.
 

Outdrive1

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Lol yes identical
Most of the older ones have that. My 78 does as well. I’ve fixed them and they come back.

The later model boats have better materials. Bi directional glass and vinylester resin. The old boats are matt glass and polyester resin and not nearly as strong structurally. Those materials weren’t available back then.

Anyhow there isn’t much you can do to stop that from happening without spending real money on the boat or laying up a new deck. Kornowski can fix it but he cuts the deck off to do it.


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farmo83

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What is the definition of older in regards to this ?

70's ?
80's ?
90's?
etc
 

Outdrive1

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What is the definition of older in regards to this ?

70's ?
80's ?
90's?
etc
I know my mid 90’s boat had zero stress cracks. Different materials and layup schedule.


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lenmann

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The new ones look like this under the deck at the bulkhead. Note that the bulkhead is 1 1/2" thick marine grade plywood and the 3/4" pad on top of it spreads the deck load. Coring under the deck is also thicker at 1/2" IIRC. Picture taken at Schiada last year.

5660FCBE-3420-4AAE-A953-76F5FCBD15B1.jpeg


The old ones (this is my '79 gem) look like this. A 3/4" ACX plywood bulkhead and a plywood wedge plus 1/4" balsa to support the deck load. Note the "whitish" areas at the inboard edge of the bulkhead to deck joint. The white means that the laminate has yielded and/or delaminated which results in the stress cracks on the other side of the deck in the gel coat.
This was state of the art construction back in the day. Pretty safe to say nobody expected or built these boats to last 40+ years.

B80984CA-0787-430A-9B7F-DFBD9E6A138E.jpeg
A938759E-524D-4428-8DB0-3A04BE7DA19B.jpeg
 

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lenmann

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Most of the older ones have that. My 78 does as well. I’ve fixed them and they come back.

The later model boats have better materials. Bi directional glass and vinylester resin. The old boats are matt glass and polyester resin and not nearly as strong structurally. Those materials weren’t available back then.

Anyhow there isn’t much you can do to stop that from happening without spending real money on the boat or laying up a new deck. Kornowski can fix it but he cuts the deck off to do it.


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@Outdrive1 do you remember how the cracks in your '78 were fixed?
 

Outdrive1

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@Outdrive1 do you remember how the cracks in your '78 were fixed?
They grind them out and fill them back in. If they go into the non skid you can’t really fix that section. But you can fix up to the nonskid.


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obnoxious001

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They grind them out and fill them back in. If they go into the non skid you can’t really fix that section. But you can fix up to the nonskid.

Kornowski is able to match up the non skid I believe.
 

welldigger00

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Kornowski capped my buddies boat, and removed the cleats, and was able to match the nonskid reasonably well. You can still see where the repairs were made. If you look at a certain angle, you can see a pattern in the non skid like rows left behind in carpet after vacuuming. It’s almost impossible to replicate that. That best and the worst thing about a schiada is the non skid!


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