I'm new to sailing, and this is my first boat. The information you have all shared has been priceless, if sometimes alarming! I have a problem with leaking water through the hull chain plate penetrations through the deck, which was noted in the marine survey. Thank you, Maine Sail, for your advice concerning the use of silicone sealant! My background is in engineering and construction, where silicone sealant is the "Gold Standard". Butyl tape it is! However, I have learned through the grief experienced by Malthius2 that the wood between the inner and outer layers of fiberglass can become saturated and deteriorate with terrible consequences. Wet wood, unable to dry through evaporation, will quickly turn to mush and is structurally worthless. My question is: Does anyone have any suggestions regarding these penetrations- how to seal them, and if necessary, how to strengthen the area around the plates if it proves to be deteriorated? Thanks in advance for your thoughts!
Leaking at Chain Plate Penetrations
- Thread starter Greg Olausen
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Remove the chainplates (and inspect them for cracks while you are at it). Cut back the wood core material for 1/2" or so around the chainplate deck openings. If core is wet, dry it and saturate it with epoxy resin. Then replace the removed core material with epoxy putty. Reinstall the chainplates, bedding the escutcheon plates with your preferred goop. West System's booklet is a good resource and can be downloaded here
Saturating wet wood with resin is a poor stopgap as is routing out wet wood with bent nails or allen wrenches. Cut off the top fiberglass skin back to dry wood. Glass in new treated 1/2" plywood, replace glass skin on thickened resin on top of plywood. You are rebuilding the deck.
B4 you go "crazy" "worrying" about what MIGHT be there, remove one and find out. Then decide what you want/need to do about it depending on condition. I just removed our saloon hatch because it was leaking badly, pretty sure the deck material was toast. Once removed, everything was dry. Same for one of my chainplates - maybe the PO had epopxied the hole well before my time.
I know it's good to be prepared, but you've been given conflicting advice so far, so go find out.
Good luck.
I know it's good to be prepared, but you've been given conflicting advice so far, so go find out.
Good luck.
Bill, I agree, saturating wet wood with resin is a no-no. That's why I said to dry it before applying resin to seal and re-bond the laminates. Time, heat and isoropyl alcohol can all help to dry the wood. Very few of us have had to do the kind of deck rebuild / recore that Phillipe of Mathurin II did (he has links in the H37C Knowledge Base sticky post). Usually just routing back the core with a bent nail or allen wrench and sealing with thickened epoxy prevents future damage from leaks. If small areas of core are damaged around the chain plates, then the injection method described in the West System literature works fine. John Cherubini II is also a big advocate of this approach. And I don't think our advice to the OP is conflicting
It all comes down to the extent of the damage and what degree of renovation is required.Stu, does your Catalina use end-grain balsa, marine plywood or foam core in the decks?
Tough to decide how far to go or the method of repair without a moisture meter. If the chainplates have been leaking then it is likely that a lot of the deck area is wet too. The 37C deck is cored with 3/4 blocks of ply. Even if the moisture had not penetrated far, I would still cut off the top skin and recore, making sure a waterproof material is installed around the chainplate slot. Rather than gluing back the original skin, apply new stitchmat wet out with polyester resin.
Jim, hard to tell, could be balsa or MP. Here's two flicks. Maybe you can tell me?!?
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Stu, definitely marine ply, same as my Hunter. End-grain balsa is used because it is lighter but balsa will really 'wick' up water and rots fairly easily, so they orient the grain vertically between the fiberglass skins to control water incursion and also for compressive strength...hence the term "end grain balsa". Balsa turns to mush pretty quickly when the water gets in. Marine ply tends to delaminate before the rot sets in. Foam is of course inert but is harder maintain bond with. The core in your pictures looks pretty good - just some minor delamination in the second shot - a perfect candidate to the type of simple repair I was advocating.Jim, hard to tell, could be balsa or MP. Here's two flicks. Maybe you can tell me?!?
The portion of Jim's quote above certainly was my experience for my only core repair project; which was the cockpit sole under the pedestal. Total area of that segmented section was 4-5 ft2. After routing around the edge of the top skin, it was a real devil to pry it away from the plywood core. Then again even more of a devil to separate the plywood from the bottom skin with a sharp wood chisel followed by a belt sander. Not a bit of rot to the plywood and all firmly attached to the top and bottom skins. Just the layers of the ply itself had delaminated as Jim has already talked about. If I was to do this cockpit sole repair again, knowing what I do now, instead of removing and then replacing the top skin, I would have drilled numerous holes (say 3/8" in a nice pattern) in the top skin when the forecast was for hot dry weather. Inject acetone or denatured alcohol into the holes which then would have run out of the pedestal cut-out hole. (After the pedestal is removed of course.) Then after some time for the core to dry out in the hot sun, inject a somewhat thinned epoxy resin into the holes. Vibrate with something to promote flow of the resin into the voids. Cosmetically fill the holes. Repaint.
Just an observation that the original poster's location is Ventura, CA. Generally a pretty dry place. Most often just a few rain events per year. If his boat has always been in Southern California, very possible that water damage to the core around the chain plates doesn't extend very far if at all. Probably just packing routing through any found plywood delamination for say 1/2" and then packing with thickened epoxy would fix enough to last the life of the rest of the boat?
Thank you all for your recommendations- at least I don't feel alone with this problem. Yes, the boat is in Ventura- but California perpetual sunshine is a myth. Currently, it's rainy and cold- no time to tackle a project best left for warm, dry weather. I will use Stu's advice and check a couple of known leaking penetrations first to estimate the extent of water penetration and damage, and plan accordingly.
Apparently, the consensus is to use a thickened epoxy packing or "plug" between the chain plate and sound, dry wood. This means the epoxy acts both as a structural filler and a waterproof sealant, bonded to the plate and the deck. This suggests there is little or no relative motion between the plate and deck, which is surprising. My initial thought to use silicone sealant- a "no-no" per Maine Sail- was based on the bond strength, longevity, and flexibility of silicone to allow for movement. Should I be wrapping butyl tape around the chain plate at the deck penetration? Is there any other waterproof caulks or sealants appropriate for these penetrations?
May I take this opportunity to wish you all a happy holiday season!
Apparently, the consensus is to use a thickened epoxy packing or "plug" between the chain plate and sound, dry wood. This means the epoxy acts both as a structural filler and a waterproof sealant, bonded to the plate and the deck. This suggests there is little or no relative motion between the plate and deck, which is surprising. My initial thought to use silicone sealant- a "no-no" per Maine Sail- was based on the bond strength, longevity, and flexibility of silicone to allow for movement. Should I be wrapping butyl tape around the chain plate at the deck penetration? Is there any other waterproof caulks or sealants appropriate for these penetrations?
May I take this opportunity to wish you all a happy holiday season!
Greg, good luck. Our'sd is a 1986 boat. Those pictures are of our saloon hatch, which lasted all 26 of those years bedded with, YIKES!!!, 3M5200. Many of us used silicone for years for chainplates. Here are some photos I took recently using butyl: http://c34.org/bbs/index.php/topic,7265.0.html
Jim, thanks for your identification.
Jim, thanks for your identification.
Jim's initial response and link to West System's Fiberglass Repair manual are right on the money and answered all questions concerning these repairs. Kindly disregard further questions about relative movement, joint sealant etc. As an engineer, I naturally seek over-complication and wheel-reinvention when a perfectly simple solution already exists. Thanks Again, you are all on Santa's "Good" List!
Many years ago I used epoxy to bond the chainplates to the thickened epoxy surroundings, thinking it would permanently keep out the water. I was mistaken. The epoxy doesn't necessarily stick to the epoxy due probably expansion and contraction rates. It is still necessary to bed at the surface with butyl tape held by the trim plate. Dremmel a channel into the glass next to the chainplate to increase the bonding area as per concept behind countersinking fitting holes as per Mainesail.
That was a long time ago before I knew about Mainsail's butyl. I bought mine from Holland Marine Products (HMP) in Toronto, now in Port Credit. Haven't owned the boat for many years so don't know how it held up in the looooooooong term. I will now be ordering from Mainsail. He has already done the research.
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