Deck Cracking...Big Deal?

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NadoSwo
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Deck Cracking...Big Deal?

Hey all! just got a 1984 Catalina 36 about 8 months ago.  I noticed shortly after i got the boat there was some fine cracking on the deck top side, and a little back aft.  Ive done some research, and im hoping its just the gel coat.  Anything I can do to fix this? or is it just purely cosmetic?  Thanks all!

 

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Chachere
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Where is this located (yes, I realize side deck, but how far forward/aft)?
We've got some small stess chacks on our '85, but nothing remotely that large.  Would want to try to figure out what could have caused it -- is there, for example, a bulkhead underneath that caused some "oil-canning"?

At a minimum I would think you should open it up a repair (lest your get water into the core)?  

Matthew Chachère
s/v ¡Que Chévere! #466
1985 C36 MKI tall rig fin keel M25
Homeported in eastern Long Island, NY

NadoSwo
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It is about 1/4 of the length aft from the bow.

What is oil canning? i have not heard that before

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Chachere
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Sorry -- repeated flexing of the surface. Perhaps over a bulkhead.   But I'm out of my depth here as to whether this is a structural problem -- or whether someone in the past just dropped something very heavy that caused a large surface crack.   Did you have a survey before buying (I would have imagined if it was there at the time a surveyor would have mentioned it)?   I would think you should sound it out to try to figure out if there was water penetration and wet core. 

 

Matthew Chachère
s/v ¡Que Chévere! #466
1985 C36 MKI tall rig fin keel M25
Homeported in eastern Long Island, NY

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pkeyser
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Do a little light thumping with a hammer and see if you can hear differences in this area vs. an undamaged area. (A "thud" vs. more of a sharper rap). A thud indicate some water migration and laminate/core damage and a need for a permanent fix. (Or use a moisture checker.) If there appears to be no water migration/damage, you can probably get by with a temporary fix for a season or two. Clean with a solvent. Let dry and apply Captain Tolley's Creeping Crack remover. Clean off any excess. It will likely create a little localized discoloration to the deck, but it does a pretty good job sealing cracks. 

This crack appears to be at sharp angle to any bulkhead position so probably not stress induced. Additionally, oil caning stress would probably produce cracks parallel to the cabin trunk/toe rails. Thinly applied gelcoats, or incorrectly catylized gel coats (at the factory) are more apt to develop cracking over time and don't necessarily point to deck or hull overstressing. 

Paul & Wendy Keyser
"First Light"
Newburyport MA/Rye NH
2005 C36 MKII #2257
Wing, M35B

NadoSwo
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Thanks! i am just hoping its not structural or any structural integrety is not lost from this. Im in Virginia right now on orders, but will be back home in a couple weeks so ill try that!

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GaryB
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The deck has plywood as it's core. It would appear that the screw for the stanchion that is in the crack would be where water could have started to invade the core. The fact that it is so straight it seems that this follows a butt seam of the plywood underneath. My guess that over the winter the moisture and freezing put pressure on the seam causing the crack. I suspect you will find moisture and you do need to seal to prevent further damage. 

Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: East Boothbay, Maine
Home: Auburn, Maine

NadoSwo
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ill try and take care of the moisture, thanks! the boat has been in san diego so no freezing here must just have grown over time and i missed it. 

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KevinLenard
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After our grounding we now have a LOT of stress cracks in the gelcoat that will require fiddly repairs to be done, but none ot fhem seem to be through to the core.  In YOUR case, however, I would get a moisture meter reading all around that crack to check the core.  A repair is needed for sure and Catalina Direct or Catalina themselves do have grey-coloured repair material available, I believe.

Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada

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