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Randomish thought on sealing deck pentratio

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Volksaholic
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Initially Posted - 05/29/2022 : 09:57:28

I bought my boat last fall, identified all the leaks I could find after the first rain, then taped leaking hardware before tarping the boat for the winter. One of the leaks was the port chainplate, which I've cleaned up and inspected. Bulkhead is stained but not soft, chainplate doesn't show any sign (to my eye) of damage or corrosion. Lower stay eye bolts look solid to me and cleaned up well. <Big sigh of relief!>

I will give the previous owner credit for keeping the water out. His widow says he was pretty meticulous and diligent about resealing deck hardware, and when I inspected the boat before purchase I could see that there were leaks but I have yet to find any sign of softness or rot in the deck or below deck. The boat sat on its trailer for 5 or so years after he got sick so I suspect much of what I've found happened after they quit sailing her.

The hardware I've found so far has been sealed with silicone or something similar. I just cleaned the chainplate penetrations yesterday and found he had done a "good" job of sealing pretty much from the deck all the way to the bottom of the slot. The word "good" is where the random thought comes in.

My belief is that you want as impenetrable seal as you can get on the outside and as leaky as possible on the inside. I've gone through several threads on the subject and I've never seen that mentioned, and in fact one I read from 2019 or 2020 on this forum it's implied that to goal is to prevent leaks to the inside. Seeing how deep the previous owner got his chainplate sealant, I think this was his intention.

The difference, as I perceive it, is that I don't want water getting under the deck, but what I want even less is water being trapped between the deck and cabin interior. If it penetrates the deck I would rather see it appear at the source as soon as possible rather than have a dry cabin and hardware sitting in a pool of water, water soaking into the core, or water forced to find some other exit point. In the case of the chainplates, they're pretty open on the underside so if I only seal at the deck and any water gets in it will show itself and then the core will have a chance to dry out. I live in Utah where we have low humidity and things dry... your mileage may vary. :)

I like the idea of "coring" the penetration with epoxy as is discussed elsewhere, and that would prevent the core rot and migration issues, but it wouldn't prevent the hardware from sitting in a puddle. This boat came off the Great Salt Lake. For the uninitiated, the GSL saline content would make ocean water taste like a clear, Rocky Mountain spring. It's the LAST thing I want trapped under the deck!

This rambling post is really about the idea that I WANT to see water appear in the cabin if the deck is leaking. When I resealed the windows I did it with this idea in mind. I'm not trying to start a debate but I would love to hear you folks with a hell of a lot more experience than me, which is probably everyone on this forum, convince me I'm wrong if that's the case. Maybe if I spend enough time below deck on my boat I'll decide that having water trapped is preferable to dealing with seeps and drips in pursuit of the perfect deck seal.

Oh, and if it's not evident from this or my previous posts... I tend to over think things and I suck at keeping my posts short so people will actually read them! :D

Paul
1981 Catalina 25 TR/FK
Soon to be named either Fiddler's Dream or Fool's Errand depending on what it takes to get her into shape

Stinkpotter
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Djibouti
9047 Posts

Response Posted - 05/29/2022 : 15:00:06

Fully read (rhymes with red)... Good points! I, too, am an over-analyzer. One possible consolation is I don't think salt is a threat to wood as it is to metal, and higher salinity might even be less of a threat there. (Wooden boat bottoms become saturated with saltwater, expanding the wood to close the joints, and it seems less of a problem than rainwater is to the rest of the boat.) The upper shroud chainplates are generally the most difficult to seal--they are the one place where I used silicone in order to maintain the elasticity of the seal. As for allowing "leakage" below, I'm not sure how you'd do it or if it's necessary. From the chainplate opening in the overhead liner, I suspect (but can't prove) water will run down the inside of the liner to the hull-deck joint, and might end up on the cabin shelves or in the bilge--I don't know. It might even be worth an experiment--a key step in over-analysis.

Let's hope Leon Sisson reads and responds to this--he's our master rot preventer (among many other things).

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Edited by - Stinkpotter on 05/29/2022 15:05:37

Volksaholic
1st Mate

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Response Posted - 05/29/2022 : 15:29:18

I wasn't thinking of the wood as much as the metal. Kind of to your point, I'd expect that plate to "move" more than any other deck penetrating hardware. If I understand the nature of stainless, if it's chafing it is likely to rust so if it's sitting in a pool of salt water and chafing I would expect it to be worse.

And I put "move" in quotes because even it the chainplate is immovably attached
it would see the equivalent of movement relative to the deck. It's the only thing that comes to mind that penetrates the deck but is attached to a bulkhead so any flexing or distortion of the deck chafe on that plate. The lower shroud bolts will experience changes in the angle of force but will move with the deck.

On a related note, I was going to seal and reinstall the chain plates between rain showers but as I was cleaning them up I noticed that the slot was either misdrilled or got chewed up along the way. This is the chain plate that was leaking and the extra length of the slot was full of old caulk. It extends just beyond the end of the cover plate. I'm going to have to fill that with epoxy or I don't think anything will keep it from leaking for very long. I was going to attach pics from the phone but I don't see a way to do that.

Paul
1981 Catalina 25 TR/FK
Soon to be named either Fiddler's Dream or Fool's Errand depending on what it takes to get her into shape

Stinkpotter
Master Marine Consultant

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Djibouti
9047 Posts

Response Posted - 05/29/2022 : 19:34:52

The way to present photos is described in our Testing forum--essentially it involves putting the photo on a photo site (although some make use from there impossible now), or putting it on the association Photo Gallery (menu to the left). From there, you can copy the URL of the photo; then in your post, you can click

, and then paste the URL between the two square brackets for the IMG tags. Easy-peasy

. (I just did the last part to include the button image.) But from my phone, it's a little more messing around than I'd want to do. (I'm old.)

I wonder about the elongation of the chainplate slot, since it should be limited by the SS frame on the deck, but your instincts sound right. With these old boats, we often have to go with our instincts and see what works. I think yours are good... But it never hurts to see whether someone else already has--that's what we're here for!

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Edited by - Stinkpotter on 05/29/2022 19:42:06

Voyager
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Response Posted - 05/29/2022 : 19:46:58

Paul, It looks like you�ve put a great deal of thought and some time into this. Not to be a bummer but aware, One failure mode for stainless steel is called crevice corrosion. SS can and will resist rusting and corrosion if it gets wet, and stays wet for awhile. The insidious crevice corrosion works like this: in an atmosphere starved of oxygen, stainless will begin to fracture microscopically allowing water to get deeper into the material. Eventually the cracks will cause a failure.
A typical situation is when stainless steel wire is swaged onto the terminal connector with the open end of the connector facing upwards. If there are voids in the swaged ends, the stainless will become full of water and devoid of oxygen very quickly. This can cause your stays and shrouds to fail, dropping the rig.
If a chainplate suffers crevice corrosion, it could eventually fail with the same result.
Unfortunately, there are no visible signs of the process taking place unless you strike the chainplate with a hammer from time to time, and cause it to fracture. Good news is that it doesn�t happen very often.
So your idea of keeping the water out, but if it does get in, it hopefully will drain quickly.

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Volksaholic
1st Mate

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Response Posted - 05/30/2022 : 05:05:37

Thanks Dave. I'm sure I could have sorted it out on the phone... but I was sitting in the storage lot after quickly taping the chainplate and shroud bolt holes up after getting hit with another thunderstorm. The rain had broken so I thought maybe I could get things cleaned up and rebed the hardware with some butyl tape, but while cleaning up those slots I saw and dug out what looked like very old latex caulk. It could be that someone came through with a rat-tail file and extended the slot in the process of cleaning it up, but it looks more to me like sloppy factory work. I almost appears that they drill holes for the chainplate from the inside after laying out where it will penetrate and that someone wasn't too good at drilling perpendicular to the inside surface. Whatever the cause, I don't want to trust silicone or butyl to keep it dry. Unless someone has better suggestions I think I'll clean it up, paint thin epoxy in, then follow up with 'glass cloth wetted out with epoxy. Here's a link to a pic of what I see as a problem. I realize after looking at the pic that I have the slotted plate shifted so a little more of the problem hole is exposed than would be if I had screwed the plate to the original holes, but in my opinion it's too close to the edge and way wider than it needs to be.
https://imgur.com/QAOw4et

I also meant to talk to your point about crevice corrosion. This is the first boat I've bought with a stayed mast. I bought it at an auction so I only had one day to look it over and couldn't line up anyone who really knew what they were looking at so I crawled all over, took lots of pics, and forwarded the ones that I thought I needed a second opinion on to friends before deciding how much I was willing to bid. The shrouds and their attachment points have some staining but everything looked solid enough that I figured I could get a season or two out of it before biting that bullet.

After I bought the boat I read of several dismastings and failed standing rigging due to crevice corrosion where the rigging penetrates the hull. My inspection and pics would have missed that. and it freaked me out. I'd planned on pulling and resealing all the hardware on the deck anyway so I started with the shroud attachments. I've cleaned it up and inspected it as best I know how and can't find any indication of crevice corrosion or enough wear to cause me concern. There was light staining, mostly above deck, but it all cleaned up bright and shiny. I feel good about it. I still want to give the shrouds and other hardware a closer inspection but it looks to me like it's more light staining but no frayed strands and nothing that looked like trouble. My finger joints should be getting sore due to all the times I've crossed them as I work through the boat prep, but so far no huge surprises.

Paul
1981 Catalina 25 TR/FK
Soon to be named either Fiddler's Dream or Fool's Errand depending on what it takes to get her into shape

Edited by - Volksaholic on 07/11/2022 15:50:05

redeye
Master Marine Consultant

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Response Posted - 05/30/2022 : 16:36:52

< < I think I'll clean it up, paint thin epoxy in, then follow up with 'glass cloth wetted out with epoxy. >>

IMHO... some thoughts...

I don't know that you have enough room for glass cloth to stick, given that area probably has a lot of strain and movement. I'd think the cloth would crack away from the deck material which is a different compound. vinyl

you might clean it all out, and prep with MEK, let it dry out and put the chainplate strap in with strain ( rigging attached and tensioned ) and of course leave off the top plate and tape up the bottom and pour in thickened epoxy ( epoxy with micro balls ). Vaseline the chainplate, maybe but maybe not you can always get it out with a hammer.

I like G-Flex cause it stays flexible rather than cracks and it is easy to mix 50/50, but I'm sure many epoxies would work here, then butyl it up..

Even with thickened epoxy it can flow into the deck so ya gotta keep an eye on it as it kicks out so be prepared to add more if it flows into the deck. It may sound uncertain but it's really not that much of a mystery. it is a pain having to watch it so long and your container of resin, don't start a fire.

No question that point has some slight movement with the loads it takes so I'm sure that design with the separate plate on top needs butyl every few years.

I did not rebuild my deck at that point but I butyl tape sealed mine bottom of the plate and polybutylene caulked the top of the plate and screws.

the good thing about fiberglass and resin construction is it is usually easy to fix. Just some time and a little work.

Ray in Atlanta, Ga.
"Lee Key" '84 Catalina 25
Standard Rig / Fin Keel

Edited by - redeye on 05/30/2022 16:38:31

Stinkpotter
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Djibouti
9047 Posts

Response Posted - 05/30/2022 : 18:33:14

Crevice corrosion is indeed insidious--it generally happens where you can't see anything, such as inside a swage as Bruce says. Some say to watch for "fish hooks" in the cable and broken strands at the swages... To me, that's too late. Others say to X-ray the fittings... Are you kidding me??

Do you have any clue of the age of your standing rigging? 15 years seems to be the rule-of-thumb for salt water. We bought our '85 in 1999... The next year I replaced the stays and shrouds using a set from Catalina Direct, installed by a rigger where I stored Passage. He said it fit like a glove, and was of high quality--bronze open-body turnbuckles, quality swages, etc. (I had owned another boat with SS closed-body turnbuckles with lock-nuts--bad invention--just bad.)

CD also has replacements for the chainplates last time I looked. For a 43 year-old boat, I think all of these are virtual necessities for peace of mind. YMMV

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Volksaholic
1st Mate

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55 Posts

Response Posted - 06/02/2022 : 15:10:33

quote:
Do you have any clue of the age of your standing rigging?

I don't. I'll probably call former boat owner's widow. Before I bought the boat I tracked her down and chatted, and see seemed pretty in the know about what maintenance her husband had done. For now I'm assuming that it's near the end of it's useful life but unless I find a reason to scrap it this season I'm going to hold off. From my limited knowledge it looks like I've got a couple seasons left, but once I get her on the water I'll have friends or other sailors give me their opinion.

I think my comment about preferring that things leak to the interior was probably misunderstood. My point was that I don't want any deck hardware to leak, but if it's leaking at the deck I'd rather have it be easy to trace from below. In other words, all the sealant should be between the deck and hardware and I don't want to make any effort to seal below deck. Maybe nobody does that. I've just seen some posts that gave me the impression that some people seal the top and bottom of the hardware to keep the cabin dry. That seems like a bad idea to me.

You guys might be right that I can't get any fiber reinforcement into that chain plate slot. I'm probably just as well off with thin epoxy to soak the core and then thickened epoxy to fill the void that extends to the edge of the deck plate. Another assumption on my part is that I should allow some clearance for the chain plate but it shouldn't need to be any more than the clearance between the chain plate and deck plate. If the chain plate moved more than that I would think it would show as elongated screw holes where the deck plate fastens to the deck, since that would be the weakest point of resistance to that movement.

Again with the assumptions. Time will tell how many are accurate, how many finer points I'm missing, and maybe even those things that happen that seem to defy logic and physics. :D

Paul
1981 Catalina 25 TR/FK
Soon to be named either Fiddler's Dream or Fool's Errand depending on what it takes to get her into shape

Stinkpotter
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Djibouti
9047 Posts

Response Posted - 06/05/2022 : 11:46:55

I certainly agree--don't try to stop or prevent a leak from the inside.

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Volksaholic
1st Mate

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55 Posts

Response Posted - 07/11/2022 : 16:39:40

I wanted to post a quick update, but of course I spent way too much time trying to figure out how to get Imgur images to display inline with the Imgur generated link... now it's no longer "quick". I'll add a link to the Imgur collection that will probably be more permanent than images I'll share from my Google Drive. I clean out Google from time to time and use it more as transient storage. EDIT: I tried linking to the images from Google Drive and Imgur but couldn't get them to display inline. I copied them to my ISP's server for now and that looks fine, and included the URL for Imgur. Now it looks like I should resize them down a bit!

The deck penetrations for the chainplates were very sloppy, probably from the factory. It looks like they did a sloppy drill job, probably from inside the cabin, and then followed with a jig saw. I think it was from below deck because the penetrations aren't nearly as oversized from that side but it looks like they didn't make much effort to keep the drill at the correct angle. Most of these images are of the port side because that one was the worst. It appears it gave the previous owner fits; it's obvious there was leakage down the bulkhead but the previous owner must have done a good job responding by re-sealing because the deck and bulkhead are both solid. He seems to have kept it dry enough to prevent rot from setting in. Either that or the Great Salt Lake water pickled the wood and prevented mold and microbes from establishing a footing.

I could have wrapped the chainplate with tape and wax paper, but I didn't want to risk gluing it in so I made some blanks from acrylic. I built them up with masking tape and wax paper to give a little clearance around the chainplate and bolted them in place. I was shooting for about 1/16" clearance on the long sides, intending to have 1/32" on either side. On the ends I didn't worry about it and let the tape bulk up a bit because I knew I'd still be well within the area covered by the deck plate. I put butyl tape below deck to prevent the thin epoxy from running into the cabin. The deck plate screw holes were also cleaned out with a 1/8" drill bit but I didn't hollow it out with the bent nail as others have suggested. I'll do that if I have to work on it again.

I used West System 105 resin I had on hand. I mixed up thin epoxy, poured it in and used a stick to pull it up the sides where I could reach, and then thickened the remaining epoxy with wood flour and worked that in. The temperature was about 95F when I was working and I only had 205 hardener so I was a little worried I'd run out of time between mixing, pouring the thin epoxy, thickening, and working that in, so I was working fast and didn't really thicken it as much as I'd have preferred. I didn't get a pic of it but epoxy seeped under the masking tape I used. I should have used a better tape, but I was able to remove it with acetone and a plastic scraper after the epoxy had firmed up but hadn't yet hardened.

I taped off the area and used a flat file to level the epoxy. Since these last pics I've sealed it with butyl tape and snugged up the screws but need to torque them down and then flood it to see if I've got a good seal.

Here's the collection on Imgur. I know that's not as convenient as seeing pics inline but I know it works! :)
https://imgur.com/a/cK1qOZA

Paul
1981 Catalina 25 TR/FK
Soon to be named either Fiddler's Dream or Fool's Errand depending on what it takes to get her into shape

Edited by - Volksaholic on 07/12/2022 07:33:47

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