Deck core replacement project

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Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
Here's a topic that has been covered many times, cutting out and replacing wet and rotten deck balsa or plywood core. Yesterday I decided it was time to again seal the six chainplates for the shrouds. You Cherubini owners know that they all go right through the side decks and attach to bulkheads. Mine are solid but I always find wet core when I dig out the old silicone.

There is a lot written if you Google, e.g.: http://www.epoxyworks.com/19/Replacing_Core.html . So the question becomes: "is there any recent news on the subject?"

My plan is to attach the shrouds to the toerail. Then cut out a large rectangle, probably extending eight to ten inches beyond the chainplates both fore and aft and the width of the side deck, from the little step up to the toerail to the cabin side. That is as far as my thinking has taken me.
 
Jun 8, 2004
1,066
C&C Frigate 36 St. Margarets Bay, Nova Scotia
Did mine last summer...

Hi Ed,

I rebedded the chainplate covers last summer. I used LifeCaulk instead of silicone in the hopes of a longer lasting seal. Considered 3M 4200 but ended up with the LifeCaulk just because I figure it will be easier to redo the next time (maybe 5 years?). Anyway, there was only one really wet area around one chain plate. I followed the West System recommendations for bedding deck fittings (I think its in their "Fiberglass Boat Repair & Maintenance" mini-book). Baisically I removed the plywood core with a bent nail chucked in a drill and then filled in the gap with epoxy putty. There was no need to go farther than a 1/2" back from the opening in my case. I've been pretty lucky with the deck on my boat (I spent a lot of time with a moisture meter when I was looking at boats to purchase) and I always use the West System approach when bedding or re-bedding anything screwed to the deck. I think I have addressed the major areas of concern on the 37C - the dorades, the windows, the companionway and the the chainplate covers. Maybe I will do a moisture survey again (like I did before I bought the boat) and see if I am staying ahead of leaks. Might be interesting. Good to hear you are down south and out of the Winter. Up here in Nova Scotia the ice is gone and I hope to get the cover off and start work in the next few weeks.
 
Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
So Jim, you removed the chainplates in order to do that? Under my covers there is just a very narrow gap around each chainplate, maybe 1/8" or a little more(I apologize for not using millimeters). But next to one I do not see much coring under the deck f/g.

I have the books that you mention from West Systems but of course they are in Ohio. Do you do the epoxy thing while the chainplates are out of the boat? I would worry about "glassing" them in where it would be impossible to replace them.

I am pretty sure that I have more damage than I can repair just from working around the holes. At any rate they have been opened up for three days in hot sun. I'll just recaulk for now. Actually LifeCaulk is what was in there. I am trying silicone because I have such good success with it around my mast seal.
 
Jun 8, 2004
1,066
C&C Frigate 36 St. Margarets Bay, Nova Scotia
Yep, remove the chainplates

Yes Ed,

I removed the chainplates. I did them 2 at a time (P&S) so I didn't wory about supporting the mast. You need a second pair of hands to do the forward lowers because of the bulkhead. I figured it was a good idea to inspect the chainplates too. There have been some reports of cracks in these, but mine were OK. With the chainplates out of the way, any deck repairs are easy. Plus you can do a really good job of preping for the new caulking.
 
Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
Good idea, then that is what I will do. But "when?" I suppose is the next question. I have always wanted to paint the mast. Then I would want to replace the standing rigging. If I do that then I need to add a forestay and replace the solid-rod furler. And then. . . . . . . Thanks Jim.
 
Jul 24, 2005
261
MacGregor Mac26D Richardson, TX; Dana Point, CA
This is one area that needs scattered threads and info concentrated... I've learned a LOT from this group and other places... The first thing was how little I knew - in spite of how much I had already learned... :> I have to thank Maine Sail for a lot of comments there... I did not find just one source to be enough... and without the right tools - the problem can be 10x harder to work on.

When there are a LOT of problem spots to fix - one can get the "deer in the headlight" problem and just "freeze up" when starting work....

Getting the moisture meter and a light dead blow hammer was a good start. Crawling around and writing measurements on the deck made it a lot easier to see where the problems were and begin to format a plan.

I found it strange to see many spots where there was and OBVIOUS potential problem - of water entry... yet the moisture meter would show a problem 6, 10 or 15" away as where there was a "wet spot"... It took the dead blow hammer and some patience to start to trust the meter more...

Getting close to the deck lets you appreciate the 37C a lot more - but it shows there are spots where all these old boats could have problems.

--jerry
 
Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
To me this wet deck thing is mostly a concern about the chainplates and their attachment to the bulkheads. With so many of the toerail bolts being inaccessible I cannot worry about the rest of the deck. I have already taken pains to make sure that the portlights, the mast step, and the forward traveler are well sealed. Beyond that I simply tighten the bolts I can reach and forget the rest.

But when the wind is gusting over 25 I start thinking about the rigging and what is keeping the mast upright. Kind of like riding the big ferris wheel at the park and checking the bolts while swinging at the top, the remaining engineer in me I suppose.
 
Jul 24, 2005
261
MacGregor Mac26D Richardson, TX; Dana Point, CA
measuring deck wetness....

Do you have a moisture meter? would be very good to move it around deck and just see what it says... I used an erasable whiteboard marker to write numbers down on the deck - so I can step back and see what had happened....

--jr
 

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Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
No real progress Jerry. All that I have done is to open up the chainplate holes to dry out. Then I filled with silicone and recapped them. And to do that requires removing the shrouds. So I did a pair at a time, port/starboard, counting turns and adding one turn when reassembling. Because I am only here through April I want to do some sailing and not have the boat torn up. Not sure when I will tackle the 'big' project.
 
May 31, 2007
776
Hunter 37 cutter Blind River
Silicone is great for some things - like making a gasket. That is why it works well under the mast step. Chainplates are a different animal. On my H 33 a number of years ago I cleaned out the old stuff around the chainplate then poured in epoxy. Held for a while but due to flexing the epoxy let go of the stainless. (Epoxy isn't flexible enough.) On the H37 C I will route out the core and fill that with epoxy then use lifecaulk (sticks to plastics better than the rest) to finish the job. Don't forget to seal up the cover plates. A very good idea is to in fact raise up the skin under all deck fittings so that water doesn't sit there.
 
Jul 24, 2005
261
MacGregor Mac26D Richardson, TX; Dana Point, CA
that flexibility was something of the reason behind West Systems "new" product..

G/Flex has more "bend"....
http://www.westsystem.com/ss/gflex/

Still... I think you have a good point.... EPOXY around the hole... and some lifecaulk local to the metal...

I have spent "some time" - tooling and and planning on how to address a massive deck job.. having the right tools is going to be important - and they do not have to be "big" tools..... getting some experience has also been an eye opener...

It's been a good excuse for my kids and I to work on soon building a storage / work shed next to the boat... I designed and they will all help build...

--jerry
 
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