Chain Plates

[Ed Ekers]

Scott,
Thanks for the invite. I may take you up on it some day (if we see the sun again).

I may take another look at the plates. As I stated we have done the upper shroud plates so I think it would be an easy job to replace the lower ones if needed without dropping the mast. I am just not that interested in taking down the rig any time soon.

Thanks for the tip on Aquarius, I will keep them in mind should the need come up.
Talk to ya soon.....ed

[Scott Galloway]

Ed,

This is what I found when I removed my chain plates in 2004. Notice the very small shiny bronze core remaining at the center of the bolts. The red stuff is the oxidized copper remaining in the larger (outer) cross section of the bolts. These bolts sheared when I put a wrench to them. Also note the reddish hue of the chain plate on the left. I used a wire brush head on my electric drill to strip this chain plate. The green one on the right is the way the chain plates looked when I removed them. I could not strip away the red copper. I did not cut completely through any of the old chain plates to look for good metal. I used the old chain plates as templates for my new plates. And by the way, the bolthole locations on each plate were slightly different, so I needed all six plates to use as templates. I wrote the locations on the blue tape so that I would know where to place the new chain plates.

[ebb]

I think that two years ago Ed's question about Ariel chainplates was answered.
Then there's ebb's way fat posts on what he thinks is related stuff!

Today,  6/5/10, littlegull's exterior bronze chainplates get installed.  
There will eventually be a shot of them on the Gallery page.

 For all the words on what goop to use I've decided to go with white butyl tape with some white tube butyl to juice the bolts with for insurance.
Butyl ALWAYS stays flexible, gummy and sticky.  It is dirt cheap.  The stuff you're bolting on can be removed without prayer in the future.
It is not an adhesive, so initially leaks are theoretically possible.
Cruisers who have used butyl for their port lights are universally happy with the stuff.
Some may have used it elsewhere on thirs boats that I have missed in research.

If I still had plates coming throu the deck, I would renovate their holes as described with epoxy, and use butyl instead of expensive rubbber.
I might leave a little door of opportunity open for the use of silyl modified polyurethane.
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EDIT: The rolls of narrow buty were deformed by inconsiderate packing from an internet RV source for the tape.  The paper interleaf would unroll before the stickum leaving the butyl unsupported.  The 'tape' will deform and stick to anything it touches.  It is gummy so you cannot pull a piece off - it has to be cut with scissors - thins and narrows when pulled.  What a PITA.  So I ended up piling on deformed strips on the flat of the plate and slapping the plate onto the hull in this case) and depending on the clamping of the bolts to achieve an even 'bedding line'.  The tube butyl I used under the heads of the bolts is much thinner and viscous and would not work imco alone to mount  a fitting.  You need somw thickness and resistance in the bedding.  The tape is very sticky stuff.  
But smears  clean up easy with mineral spirits.

EDIT,  Tremendous clamping loads by fat plates and oversize bolts will conceivably squash butyl tape to zero thickness.  Did chamfer the bolt holes on the hull, so there is a small ring of waterproofing around the bolt.  Better would have been using  O-rings or plastic  washers around the hole to help keep butyl from squeezing out all the way.  They also  contribute to waterproofing the holes by creating a barrier of their own.
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Later EDIT on BEDDING stainless:
316 stainless steel survives well exposed in the marine environment when  chromium in the alloy is allowed to form c.oxide on its surface  in the presense of air.
Bedding stainless is therefor frowned upon.
Seen countless boats with bleeding rust sprouting from underneath stainless steel fittings.
In My Considered Opinion when we bed stainless we must abrade the shiney surface of the polished fitting with a scotchbrite pad. [I'm not the only one!]  
I'd bluetape off the exposed metal of a s.s. chainplate and scrub just the buried parts of the s.s. with at least a green nylon scotchbrite pad*.  
We want to prep the buried parts of the fitting to stick VERY WELL to our choice of bedding compound.  We want to create a surface on the polished s.s. that the compound wants to stick to.  
NEVER grind or sand or use any abrasive!  Don't even be tempted, you will be creating a cause for crevis corrosion.:eek:
 Use only a nylon pad.  
We can test for a well prepped surface by spraying a little water on it.  If water "runs free" and does NOT REFORM INTO DROPS we have then the best surface we can expect for bedding and keeping salt water out of the joint.  Any water out of the joint.
as always: imco.
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*  I've frosted favorite glassware over time by cleaning with green  nylon kitchen scrubbers.  The stuff is sharp and abrasive in its own right.

[CapnK]

Looking forward to those pics, ebb!