Sealing cabin top seams

rukidn

.
Apr 23, 2012
160
Catalina 310 258 Sandusky, OH
A while back I posted the rebuild of our companionway hatch cover. Moisture damage. Now I need to reinstall and caulk the seams. After reviewing so much online information, I remain confused as to the best choice to caulk these seams. Not 5200, other 3M sealants yellow, some chalk like Lifecalk. What have you use with success? Tools easily, stays white and clean, isn’t permanent, etc.

Thanks! Ed
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
I know my monitor grows blurrier as I get older, but I don't see where these seams are in what appears to be a solid piece of plywood.

1620865489178.png



Is the cabin top to be painted or ........................... ?
 

rukidn

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Apr 23, 2012
160
Catalina 310 258 Sandusky, OH
You’re looking at the bottom in the photo. I opened and replaced the balsa core due to extreme moisture. Top is white gel coat edges and gray nonskid. Covers companionway sliding hatch. Seam in question is between this part and the cabin top itself.
 
Feb 26, 2004
22,759
Catalina 34 224 Maple Bay, BC, Canada
If it goes on top of something asnd doesn't ever move:

BUTYL TAPE from Maine Sail Bed-it-with-butyl Not the crap from the hardware store.

Nice work there. :plus:
 
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Likes: Alansails
Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
I was having a difficult time visualizing “the seam”. Do you mean the cut line you used to open up the panel and remove/replace the rotted balsa?

If so then you need to be using epoxy and fiberglass cloth. You need to adhere the fiberglass to the balsa so that the skin and balsa are one solid piece. Not doing it leaves a void. You will know the void exists when you step on it. It will eventually crack the fiberglass.

When the piece is solid you’ll be filling the seam with thickened epoxy. I might think about using Thiox. Easy to apply along a seam line.

Depending on the space I would add some strips of cloth and resin overlapping the seam to reduce the chance of water getting in there.
 
Jun 8, 2004
2,841
Catalina 320 Dana Point
I've heard this piece referred to as a "sea hood" or "spray hood" it fits over the area of the companionway slide when it is opened. There is a seam about 1/4" between it and the surrounding deck which is caulked with something at the factory when built. I think butyl would be good for the bottom edge but something still required to caulk above it.
 
Jun 8, 2004
2,841
Catalina 320 Dana Point
Found some photos on the 320 org site that show the area but I couldn't find any reference to what he was using for caulk.
Seahood
 

rukidn

.
Apr 23, 2012
160
Catalina 310 258 Sandusky, OH
There is a seam about 1/4" between it and the surrounding deck which is caulked with something at the factory when built
Yes, this finished seam between hood and cabin top. Factory caulk essentially gave it up years ago.
 
Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
If that is the case then butyl tape could work as a bedding caulk. Or a bead of 4200.
 
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Likes: Alansails
Dec 21, 2020
82
Catalina 310 Lake Hefner
I have the same problem. I’ve kicked the van down the road by caulking everything up. You may also want to check the 2” or so screws that hold it down. There may be water in there too. As you are on top of all this, might as well keep fixing.
I use a combo of materials. Flex Seal has a new white adhesive caulk that is working well for me. I inject it as deep as possible into any holes first then coat the screws as I install them. I use butyl tape too and just 50 year caulk from the Depot. I’m relentless on keeping water out. Unfortunately for both of us, the previous owners were not.
Thanks for posting. Very helpful for me.
 

rukidn

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Apr 23, 2012
160
Catalina 310 258 Sandusky, OH
I guess I did confuse some by posting photos of only the bottom of the hood. Project is now complete. This post was inquiring the best caulk for the sky-facing seams. I caulked the seams with LifeCalk.

I'll update the prior post with specifics beyond caulking. /Ed
 

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