Chainplates

[DaveBMusik]

It's time to go after some small chainplate leaks. I have read all of the forum posts, tech notes and Wiki's, many with conflicting info. I plan to use MaineSail's method to repot the bolt holes and use butyl tape rather than polysulfide.

My question - What is the best way to seal the plywood in the actual chainplate cutouts?

I have read that people simply brush on epoxy, some fill the opening (with tape on the headliner) and then drain it before it sets and some let the complete opening set and then cut out.

If I fill the entire opening with epoxy and let harden, I'm assuming the best way to open it up is to drill out the four corners and then use a saw to make the straight cuts.

Should the cutout be the exact same size as the original or could it be a tiny bit smaller?

Has anyone used some kind of a filler piece (plastic sleeve, etc,) slightly larger than the chainplate to fill the center of the hole and then fill around the outside with epoxy?

Thanks!  Dave

[Noah]

Are you sure you have any damage to the deck core? Perhaps all you need to do is remove the top plates on deck, re-bed and not bother with epoxy, etc.?

[KWKloeber]

Dave

I have been doing a lot of rebedding/core repair and sealing on a J/120 lately,  I used Mas Epoxy low viscosity, no filler for the initial fill so it  would infuse into the core as well as possible.  Then sucked out and filled with thickened Mas.   The initial was with slow hardener so there was plenty of work time to infuse.

I use Mas because there is no amine blush and the mix ratio is much more forgiving (2 to 1, not 5 to 1) and can proportion a smaller amount (18 oz) using 6 oz bathroom cups -- or even 9 oz (half a cup, 3oz, is very easy to measure.)   I prefer Mas over West, though I nearly exclusively use West additives.

You can easily wax up most anything (presumably a chain plate) and use it as a negative mold (I just did some filling with waxed bolts held in place to form thru-deck mounting holes reinforced with G-10 blocks epoxied in place to accommodate cross-over winch feeders.  As soon as the epoxy kicks (gels) just move (not remove) the item to avoid it becoming a one-piece with the boat (almost did that years ago with a rudder -- but I finally got the stock broken free the day after I had poured it in place in the tube.)

A used a 1/8" helix rotary tool (ie, rotozip) bit in a dremel to cut out a lot of cured resin.  You can do it before fully set (like the next day with a slow hardener -- rather than 4 days after a fast hardener) to make it easier, then let it fully cure after cut out.   I always have different rate hardeners handy so I can control whatever I need to.

Many typically swear by colloidal silica - I much prefer using West microfibers as the additive.

ken

[Jon W]

My 2 cents are to check the condition before drilling out the core and refilling. I've just finished my 3 starboard chainplates and doing the port side now. I was ready to do the grind out the core, replace with epoxy, and re-drill approach but found when I got in there the wood core was dry and solid so there was no reason to fix what isn't broke. For the gap, I kept it small but large enough to get the butyl tape stuffed in between the chainplate and core. Use Mainsails method to install the butyl tape, it really works great.

As an FYI - the PO had used some silicone sealant, but most was water soluble caulk. I know that because I used water to remove it. I'm giving the PO the benefit of the doubt that he re-bedded chainplates as a regular maintenance task and tub & tile caulk is a lot less hassle to remove. So wrong stuff, but the core was still fine in the 4 I've done. Hope I didn't jinx myself for the last two.

[Stu Jackson]

My 2 cents are to check the condition before drilling out the core and refilling. I've just finished my 3 starboard chainplates and doing the port side now. I was ready to do the grind out the core, replace with epoxy, and re-drill approach but found when I got in there the wood core was dry and solid so there was no reason to fix what isn't broke.

I agree.  Very good approach.  I didn't even see any wood ends, just a nice fine finish, who knew what the PO had done, looked great on all six.

Ditto on the butyl tape.  Do a search on "chainplate flix" and see what I did.

[DaveBMusik]

Thanks for the advice. I have a small amount of compression at the bolts although no cracking. I want to be prepared to address the chainplate cutouts in case I find anything. Sealing the wood certainly seems to be good insurance but I will wait and see what I find.

[Breakin Away]

Do any of you use the improved chainplate covers that Catalina Direct sells? It seems like this could be a significant improvement in sealing above the deck by completely eliminating the huge gap between the cover plate and the chainplate tab, and greatly increasing the bonding area.

http://www.catalinadirect.com/index.cfm/product/2584_772/c-34-c-36-chainplate-cover-upgrade-pr.cfm



If you have used these, do you have any suggestions for how to apply the butyl tape in a way that it is not just pushed up and out the spigot?

I had searched for notes on this a few weeks ago and did not find anything, so this thread seems to be a good opportunity to bring this up.

As for the question about how to prevent the epoxy from filling the slot, I did a chainplate job on my C250. One side was a little wet, so I ground out the rotted end balsa core (only about 1" wide) and re-filled with epoxy. I filled the screw holes and drilled, but I did not want to have to saw out the (very narrow) chainplate slots on that boat, so I wrapped ~10 mil polyethylene film around a kitchen sponge and pushed it down into the slot with Gorilla tape sealing the bottom headliner. After slow curing overnight the whole thing came out easily (almost nothing sticks to polyethylene), leaving a gap to reinsert the chainplate. This method might be modified for the larger chainplate slots on the C34.

[Jon W]

Sorry can't offer any suggestions. I thought about using these, but decided not to.

[Stu Jackson]

Do any of you use the improved chainplate covers that Catalina Direct sells? It seems like this could be a significant improvement in sealing above the deck by completely eliminating the huge gap between the cover plate and the chainplate tab, and greatly increasing the bonding area.

I don't think it's necessary.

From the "101 Topics" sticky:

Chainplate Rebedding 101 - with Bed It with Butyl from Maine Sail

http://c34.org/bbs/index.php/topic,7265.msg49430.html#msg49430

Pictures are included.   

If you fill the gap between the chainplate piece that sticks up through the deck AT THE DECK LEVEL, then this new-fangled thing isn't going to do much to help.  Think about it for a moment.  Good luck.

Your boat, your choice.   

[Breakin Away]

Yes, I had seen your post before. I know the Bed-It butyl tape is great stuff and retains its properties pretty well in the elements. But first time I saw a C34/C36 chainplate I was shocked at the size of the gap between the tab and the coverplate, and concerned that the design relies too heavily on a fat wad of sealant to keep moisture dry. I was pleasantly surprised that my surveyor reported dry decks around the chainplates, and I want to keep it that way.

If the old design is completely adequate, do you have any idea why Catalina modified them?

[Noah]

Are you sure "Catalina" modified them not just "Catalina Direct" who has no affiliation with the boat builder?

[Stu Jackson]

If the old design is completely adequate, do you have any idea why Catalina modified them?

Catalina Direct is NOT Catalina.  I don't know if Catalina modified them.  I do recall a C36 skipper who has been peddling his "new improved" chainplate covers, but don't know if these are those.

It's not a great big hole, and one actually NEEDS space for movement to, uhm, move, in that location.  Of course, the trick is to keep them dry, but for many years dumb old silicone was used, and as bad as it still is, it worked, if a skipper was bright enough to understand that chainplates should be part of normal maintenance.  They only leaked because they were neglected, or the skipper did a rotten job.

Let's take a look at these new ones:  You still need to seal the slotted hole between the chainplate and these covers, right?  But you ALSO need to seal below the chainplate cover to avoid water seeping into underneath.

That seems to be MORE work to me, with two different places for ingress.  I think it is an unnecessary complication.

[Breakin Away]

I realize that Catalina Direct is a dealer who is separate from Catalina Yachts (except for a close relationship and deep institutional knowledge since they hired Kent Nelson from Catalina). They sell parts sourced from Catalina factory, as well as other 3rd party suppliers.

In the case of the redesigned chainplates, the C36 website has numerous references to the new chainplate design being supplied by the Catalina factory, complete with names and phone numbers of Catalina employees to contact for information. So the appear to be a product of Catalina Yachts that is sold by CD and also direct by the factory. I did not have time to do a thorough search for differing opinions, but the few messages that my search turned up seemed to put this into the "DO THIS OR ELSE" category for boats prior to 2003. For $9 per cover, it seems like a no-brainer that will turn a regular maintenance item into a once every 20-30 year job.

I do not agree that the new cover provides two different places for ingress. The current cover has two places for ingress, and one of them (gap adjacent to the tab) appears to have very little bonding area and exposes the sealant directly to UV and rain. It also is at deck level where pooling can occur. The modified chainplate looks to me in the pictures like it would provide a significant bonding area in the narrow gap between the spigot and tab, thus shielding it from UV, and moves the exposed area up to an elevated point where pooling cannot occur.

I'm a little surprised that the opinion toward this cover modification here is so different than the messages I saw on the C36 website. Are the C34 chainplates a different (superior) design than the C36 ones?

I realize that it's my boat and my choice. My inquiry here is still pretty much the same: Has anyone here done this upgrade, and if so, do you have any suggestions for how to apply the butyl tape in a way that will keep it in the spigot and not just force it up and out when you push the cover down on the tab? Do you line the inside of the spigot with butyl tape, or the outside of the tab? Also, has anyone had any trouble getting them to fit due to manufacturing tolerances?

The C36 skipper that I am aware of was peddling a fully redesigned chainplate (not just the cover) on a YouTube video. While he still will make them up, Catalina's modified cover seems like a simpler, more elegant solution, and he seems to have backed off his marketing in favor of the improved cover. There's probably more on the C36 website about this, but I'm too close to bedtime to check tonight.

All my comments are based on looking at pictures and my own chainplates. I have no actual experience with these redesigned covers, which is why I'm asking here.

[Noah]

I haven't done this task (yet) but it seems to me that butyl tape would not be the best sealant to fill-up the spigot of these modified covers. Why not ask Catalina (if they are factory items) or CD who sells them, how they intended for them to be installed?

[Steve McGill]

I completed the replacement of my chain plate covers purchased from CD last year.
I removed the old covers, the chain plates and the thru bolts on each. I counter sunk the bolt holes
following some of Mainsail's suggestions. I cleaned the chain plates and all surrounding areas I
re-installed the chain plates and used butyl tape on the counter sunk bolts tightening these from below.

For the new CP covers I added butyl tape (BT) to all surfaces and installed. I then used a pick or dental
tool to get the BT in between the chain plate and the new cover on the vertical surfaces so that it was
close to the top of the new cover.

Because I was concerned how the BT would react to the UV overtime I then covered the top of the new
CP covers where it met the chain plate with  3M Marine Adhesive Sealant Fast Cure 4000 UV

Steve