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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

Removing/inspecting chainplates

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JAB
1st Mate

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USA
38 Posts

Initially Posted - 11/17/2010 : 10:01:10

Boat's on the hard. Mast is down. I'll be replacing shrouds this winter. Plus some re-bedding work (stanchions, etc.) Based on comments from others, I plan to remove and inspect/Magnaflux port and starboard chainplates, as I'm told they're possibly prone to corrosion within the out-of-sight deck.

So my question: What's the best way to remove them?

In an earlier post here, a member (Happy D) advises to lift them up and out using a screwdriver. On another (not Catalina-specific) site, others advise to tap them down into the cabin with a hammer.

Advice from people who've done it?

Edited by - on

pastmember
Master Marine Consultant

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2402 Posts

Response Posted - 11/17/2010 : 11:40:56

Making sure you have the "upgraded" lower chainplates is worth doing. The rig has so much redundancy with dual lowers and uppers that I would be shocked if chainplate failure would bring a stick down. I could see tapping on the upper chainplates with a small hammer and listening for a strange sound but I can't see bothering to remove them. If your bulkheads are shot and you will have them out anyway then sure but it seems a bit paranoid to do it just to be "thorough".

Edited by - on

John Russell
Master Marine Consultant

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USA
3444 Posts

Response Posted - 11/17/2010 : 12:27:13

JAB,

Since your kinda new to this forum, I thought I'd let you know that there are very few people here that know more about the C25 than Frank Hopper. Frank's a former Commodore of the Association and has done extensive work on 2 or 3 C25's. If he says leave them alone, I'd consider that very carefully.

Besides, in the 3 or 4 years I've been reading this forum, I don't recall any discussion about chainplates being "prone to corrosion". That's not to say it doesn't happen, it just doesn't seem to be a common occurence here.

Edited by - John Russell on 11/17/2010 12:27:54

pastmember
Master Marine Consultant

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2402 Posts

Response Posted - 11/17/2010 : 16:29:33

John that was very kind of you to say. I am, as the forum clearly states, simply a fellow sailor willing to tell other sailors what I would do. I hope JAB gets a lot more input and weighs it all against what he feels he needs to do.

Edited by - on

JAB
1st Mate

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USA
38 Posts

Response Posted - 11/17/2010 : 18:57:23

On the corrosion question, there's some---not a lot---of evidence of moisture on one of the upper shroud's deck penetration.

I'm going by a couple of remarks I've heard, including the one posted in an online-catalog description of the chainplate by Catalina Direct, http://www.catalinadirect.com/index.cfm?fuseaction=product.display&product_ID=399&ParentCat=39 . It remarks that, "If there has been water intrusion, it will damage the plywood deck core as well as the interior main bulkhead. A chainplate that is kept in constant with moisture by the the saturated wood in the deck is also subject to crevice corrosion and failure."

Thus the plan to remove them for inspection. Techniques, anyone?

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9076 Posts

Response Posted - 11/17/2010 : 20:03:27

I had a little, not a lot, of evidence of moisture coming in around the port upper chainplate on Passage when I bought her... The survey showed no moisture problem in the deck core in that area. I lifted the frames, dug out the old sealant, and re-sealed both uppers, and "Voyager" Bruce is sailing her 10 years later. That said, I'm very hesitant to advise against an inspection, although "crevice corrosion" is often not detectable to the naked eye. CD would like you to buy new chainplates... I haven't heard of any failing on a C-25 in my 12+ years following this forum. All possible caveats apply to these comments.

Edited by - on

Dave5041
Former Mainsheet Editor

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USA
3758 Posts

Response Posted - 11/17/2010 : 20:10:05

I had leaky chainplates in the beginning until I rebedded. I removed the uppers and the sealant on the core was intact and no damage and no corrosion. Some older boats have chosen to replace/upgrade chainplates, but I don't know of anyone who has actually reported a problem with the chainplates. I wouldn't bother if they aren't leaking.

Edited by - on

OJ
Master Marine Consultant

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4382 Posts

Response Posted - 11/18/2010 : 08:12:09

Joe,

FWIW, I used to work for a heavy (very heavy) equipment manufacturer and Magnaflux was used to identify cracks not readily seen by the naked eye.

I am not a metallurgist - but other than surface rust in salt water environments - I've never seen evidence of corrosion on stainless steel in a marine application.

I replaced the chainplates for the lowers on a 1981 C25 as an upgrade (those plates were considerably thicker.) The ones on my 1989 C25 are an angle iron profile - better yet.

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9076 Posts

Response Posted - 11/18/2010 : 08:40:20

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by OJ
 ...other than surface rust in salt water environments - I've never seen evidence of corrosion on stainless steel in a marine application...
<hr height="1" noshade id="quote"></blockquote id="quote">Nobody knows for sure what caused this failure:

Or this:

Metal fatigue, crevice corrosion, crevice corrosion causing metal fatigue, metal flaw causing crevice corrosion,.....

And no, crevice corrosion in stainless does not look "rusty."

The good news is the chainplates aren't subjected to bending forces like these pintles were.

Edited by - Stinkpotter on 11/18/2010 08:41:33

bigelowp
Master Marine Consultant

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USA
1773 Posts

Response Posted - 11/19/2010 : 07:31:08

For what it's worth . . . . I would think (as I don't "know") that the design and ruggedness of construction would make the chain plates on the C25 an item of minimal concern. As long as the through-deck bedding is maintained and no unusual stress (like surviving a hurricane on the hard with mast up, etc) has been experienced you should be good to go. A normal survey will always include a look at the chain plates as on most earlier fiberglass boats they were THE area of concern (be glad you don’t own a Tartan where they are fiber glassed in).

That said, the quality of more recent –mid 1990’s to date – stainless is more suspect as foreign suppliers, who push the envelop regarding “meeting spec” are taking over the hardware world. The government has had real issues with “bogus” (certified to be of one grade but in reality deficient) stainless. One example: I bought from CD a replacement balanced rudder from IdaSailor in 2007. I put the rudder on my boat and before launching it had significant surface rust just from one short rain shower! I was told that the fittings were all stainless; clearly mine were not of standard. At work we have had similar issues with stainless fittings not lasting as long. So, I would be MORE concerned with replacement chain plates, pintals, hinges, etc than with 1978-1990 vintage hardware.

Again, for what it’s worth . . .

Edited by - on

JAB
1st Mate

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USA
38 Posts

Response Posted - 11/19/2010 : 07:53:35

Thanks for the discussion on the virtues of stainless steel metallurgy in various grades and sources. However, I get back to the original question:

What's the easiest way to remove upper-shroud chainplates, Up or Down???

Edited by - on

mlg3733
Navigator

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118 Posts

Response Posted - 11/19/2010 : 12:46:48

I pulled my chainplates up when I resealed them, only because there are fewer chances of scratching the bulkhead, but in fact it makes no difference either way.

Edited by - on

Happy D
Admiral

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921 Posts

Response Posted - 11/19/2010 : 19:06:50

You've already spent more time typing that is required to remove the chain plates. Unbolt them from the bulkhead, put a screwdriver through the shroud hole and pull. If they don't come up, wack them down with a hammer. Have someone guide the plate so it doesn't scratch the bulkhead on it's way down.
If you feel the need for new ones, purchase the new stainless at www.onlinemetals.com and drill new holes. Way cheaper than CD.
Clean everything up, put down a large gob of Lifecaulk and screw the cover plate back on. Good to go.
For what it's worth, My deck was wet for along time, with fresh water. My chain plates look perfect. No idea with salt water.
Dan

Edited by - on

Dave5041
Former Mainsheet Editor

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USA
3758 Posts

Response Posted - 11/19/2010 : 21:05:11

Optimal re-installation: trim the upper opening (deck) slightly wider and longer the the lower (liner) with a dremel, grind out the core and and seal with epoxy, fill with epoxy putty so all four sides taper from the deck to the liner. When you re-install the chainplate, slightly overfill the the opening and let it cure. When you replace the cover plates they will compress the polysulfide more tightly and insure a long term seal.

Edited by - on

Happy D
Admiral

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921 Posts

Response Posted - 11/20/2010 : 03:48:58

What Dave mentions is Optimum, but not at all easy. I cut the core back and filled with epoxy, with the chain plate through the opening. I used packing tape on the chain plate so the epoxy would not stick to the chain plate and waxed it. I did this with the bulkheads removed. I clamped the chain plate in temperoraly.
It was very dificult to get the chain plates out after the epoxy cured. Once they were out, I used a long big file to clean up the opening so the chain plate would slide through the hole.
It was a lot of work and a lot of dust in the cabin.
Optimum, yes, but not worth it to me.
I think if someone would just re-bed the CPs every year, they would never leak. My 2 cents

Edited by - on

Dave5041
Former Mainsheet Editor

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3758 Posts

Response Posted - 11/20/2010 : 08:03:08

You are correct, but you won't need to rebed every year. The trick to my approach was using Poxystick, a stick of the 2 parts that you knead to activate. It is the consistency of modeling clay and can be completely shaped with a wet tongue depressor before it sets up to eliminate the grinding. You can also use modeling clay to temporarily seal the lower opening when you re-install the CP if the gap is to big when you add the polysulfide

Edited by - on

Happy D
Admiral

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921 Posts

Response Posted - 11/21/2010 : 10:28:30

<blockquote id="quote">quote:<hr height="1" noshade id="quote">The trick to my approach was using Poxystick, a stick of the 2 parts that you knead to activate. It is the consistency of modeling clay and can be completely shaped with a wet tongue depressor before it sets up to eliminate the grinding. <hr height="1" noshade id="quote"></blockquote id="quote">

The problem with using a product like that or Marine Tex is that there remains a transition between the wood, the fiberglass and the putty that was used. This transition has no adhesion and will still allow for water intrusion. As far as strength to resist crushing from the fasteners that process will work fine, but the possibility for water to migrate past the putty and saturate the wood still exists. The best way to epoxy seal these areas are with an unthickened epoxy to first saturate the wood and prime the area, so to speak. Taping the bottom of the opening and filling with unthickened epoxy fills all the voids and saturates all the surfaces. The unthickened epoxy is then drained from the cavity, if there is any left and then thickened epoxy is flowed into the void. If the unthickened epoxy drains out or is absorbed, I keep filling it back up until no more is absorbed, then I drain it. This also prevents the wood from siphoning epoxy from the thickened mixture causing a weak spot. After saturating the area with unthickened epoxy, I flow a thickened mixture in, tapping the surface to release any bubbles to the surface. I'm always afraid that if pack in to thick of a mixture, I'll be sure to have a void and that's bad news.
In reality, after the thickened mixture cures, it should be ground back and sealed with unthickened epoxy once again. That assures a water tight opening. That's the way I do it.

Edited by - on

Dave5041
Former Mainsheet Editor

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USA
3758 Posts

Response Posted - 11/21/2010 : 20:54:54

You have a point, but I addressed that issue in the first description. I first coat the core and internal surfaces with liquid epoxy to seal it. Putty or the thinner MarineTex will bond effectively, but the likelihood of voids for water penetration certainly increases with increased viscosity of the filler.You will get the best bond If you back fill while the seal coat is still tacky after it starts to set up, otherwise let it fully cure and give it a light wipe with acetone then alcohol if it makes you feel better. I mention the wipedown for the purists - I have never seen a bond failure over a thin coat of epoxy with or without a wipe.

edit: and earlier I should have said on re-install, slightly overfill with polysufide

Edited by - Dave5041 on 11/21/2010 20:57:47

Happy D
Admiral

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921 Posts

Response Posted - 11/25/2010 : 05:31:58

<blockquote id="quote">quote:<hr height="1" noshade id="quote">otherwise let it fully cure and give it a light wipe with acetone then alcohol if it makes you feel better.<hr height="1" noshade id="quote"></blockquote id="quote">

Sorry Dave, but I completely disagree with this statement. After epoxy fully cures the surface must be roughened up to create a tooth for the next layer of epoxy to adhere. Once the epoxy fully cures there will be no chemical bonding between the new and the fully cured epoxy.

Fully cured epoxy creates an amine blush that must be removed before any sanding can take place. Amine blush is water soluble only. Acetone or alcohol will have no effect in removing amine blush. Amine blush should be removed after any epoxy hardens up even if it is not fully cured. It takes no time to scrub it a little with a scotchbrite and water.
Even the so called no blush epoxies get a wash with water just in case. Why chance it?
I would hate for someone to read this and think that simply wiping fully cured epoxy with acetone or epoxy is preparation enough to apply subsequent coats of epoxy, no matter how thin.
To get the bond correct certain steps need to be made. Anything short will produce less than design results.
The West System web site will provide the correct information to anybody that want to repair their boat no matter how small the repairs.

Edited by - on

OLarryR
Master Marine Consultant

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USA
3440 Posts

Response Posted - 11/25/2010 : 08:25:30

If you wind up buying stainless steel from a non-marine distributor, check to see if they have stainless steel low carbon (304L or 316L). I do not believe you will ever have to deal with this again anyway but stainless steel grades with lower carbon content will be better at holding up to moisture/stagnant seawater that is in contact with stainless steel such as just below the deck area. Stainless steel is fine for above deck and mostly okay in moving seawater but in contact areas where seawater is stagnant, I have seen some industrial cases (past experience design, etc on process and power plants) involving stainless steel pipe flanges, etc that had the entire flange surface disintegrate. This was after many years....15 years plus. In the one case I am thinking about, we had the entire stainless steel piping loop removed and replaced with carbon steel cut into 4 foot sections with pipe flanges attached and then had each entire section of the piping, flanges, etc coated w/polyethylene using a fluidized bed process....This all to avoid future stainless steel compatibility issues w/stagnant seawater.

Edited by - on

froell56
Deckhand

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USA
14 Posts

Response Posted - 10/24/2011 : 15:19:04

New to this Association... my first post.

I too have planned to pull and inspect the chainplates on my '77 model C25. They aren't leaking but but i'm sure they are original and haven't been inspected in over 10 years. Can anyone convince me this isn't necessary as there are plenty of other tasks that I could spend the time on? Thx

Edited by - on

pastmember
Master Marine Consultant

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2402 Posts

Response Posted - 10/24/2011 : 15:51:52

catalinadirect.com shows this as an upgrade for older C 25 lowers, (they did occasionally break from corosion), they are an improvement but far less than the angle bracket on the later C 25s.

I liked the ones in the later 25s so if I were you I would contact Catalina parts and see if you can buy those.

As for the uppers, they are very robust and presuming your bulkheads look good probably are fine.

Edited by - on

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