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Best method for bedding Morgan chainplates???

Wanderlust

New Member
We've recently replaced our standing rigging after a dismasting off the southern coast of Dominica. The failure that caused the dismasting was in the bolts securing the top plates to the chainplates through the deck. The bolts securing the port cap shroud all broke about 1/3rd of the way up the head of the bolt (above the threads) and our mast broke just above the spreaders. What I'm looking for is a method of bedding the chainplates that prevents interior leaks and moisture intrusion to the head of bolt, but also allows easy inspection of the bolts and chainplates on a regular basis.

I currently use 3M 4000 to bed the chainplates which has prevented any interior leaks, but seems to have allowed water intrusion at the head of the bolts and is a pain to inspect. I'm considering cutting sturdy gasket material for the deckplate and then wrapping the head of bolts with butyl tape, which makes for easy inspection, but I lose the strength of the adhesive.

Does anyone have a method they consider "best practice" for bedding Morgan's somewhat unique chainplate design? Any input is welcome
 

terry_thatcher

Terence Thatcher
Butyl tape around the head of bolts. See advice on Compass Marine web site/. I also bed the covering platesand all other deck fittings with butyl.

I am sorry to hear about the failure. I t must have been horrifying to have the rig fail like that.
 
Where did you purchase the screws? What is the length? (So I don't have to remove to measure) And am I correct they are all the same length?
I noticed that one of the screw heads has popped up about .5 mm, so I assume hidden damage to it and they all should be replaced.
 
Heads up about using the same bolts....As Jeff Lovett indicated in this thread about 3 years ago, change out the old bolts with new. I was using the same bolts when rebedding my chainplates over the holidays and a bolt head snapped off the bolt when tightening down on the bolt revealing rust between the head and bolt itself. I had given it a once over inspection but apparently but I missed seeing anything wrong with it. So now I threw away the old ones and replaced with new. Cost about $135.00 for 24 new bolts and nuts from West Marine. I did not give much thought about trying to use the old bolts for something that is as important as keeping the standing rigging in place. I will be looking over the rest of the rigging very closely.
 
I removed the chain plates and performed dye penetrant testing. With no cracking being found I applied butly tape as bedding and around the screw heads with new machine screws, All fasteners are not created equal. I caution everyone to not accept critical fasteners from a hardware store, West Marine or anywhere else that cannot be verified as 316L stainless.
I have a passionate hatred for all slotted fasteners. Phillips, P&K, Posi-Drive, Torx or better.
 
Not aware that WM may not have the best stainless, considering the price. I will inquire with WM about the hardware to determine if that is the grade they sold me. Is there any way you can tell by inspecting them? Any markings on them to show 316L stainless?
 
They are all bright and shiny!
There have been instances in the aerospace industry where fasteners were the equivalent of melamine added to dog food. The only resource I know of are search engines and time spent drilling down to a source that can provide material and engineering numbers. I did this 3 years ago but sadly I cannot locate my source that I though I saved in my bookmarks. I recall that they were located on the east coast.
Nice folks at WM but purchasing agents probably make those decisions, not engineers
 

stnick

lee nicholas
If its 30 years old Think of changing it ! Unless you have done the metal dye test ( available at Granger ) ! Always come down on the side of safety not cost !
 

yurek

Jerzy Borzym
I'll replace my shrouds chainplates deck mounting bolts on my 384.
I would like to have them ready before disasembling chainplates.
I'm looking for dimensions and source were to buy them.
I'm not crazy about WM.
Yurek.
 

jimcleary

James M. Cleary
Yurek

I purchased the replacement bolts for the chainplates from Jamestown Distributors. Phone Number 401-253-3840. I'll measure them the next time I go out to the boat. To get the size I removed one bolt, caulked up the hole, cleaned and measured. The threads on the bolt were corroded where it passed through the deck.

Jim
 

jimcleary

James M. Cleary
Yurek

I found the receipt for the bolts. They are flat head machine screws, phillips, S/S 3/8 x 16 x 2". The cost for 30 bolts was $22.51.
The Jamestown stock number is: FSSMSFP38X2.

Jim
 

stnick

lee nicholas
Yurek

I found the receipt for the bolts. They are flat head machine screws, phillips, S/S 3/8 x 16 x 2". The cost for 30 bolts was $22.51.
The Jamestown stock number is: FSSMSFP38X2.

Jim
Where did you purchase the screws? What is the length? (So I don't have to remove to measure) And am I correct they are all the same length?
I noticed that one of the screw heads has popped up about .5 mm, so I assume hidden damage to it and they all should be replaced.
 

stnick

lee nicholas
i called Jamestown this AM they only have access to 304 SS I went to FASTNAL i ordered 316 - 3/8x16x2 nuts washers and machine screws
Cost 125.00 316 SS
 
Mates,
I have found excellent quality fasteners at McMaster-Carr, in Chicago. They have a website and a phone app. You can find almost anything there, even some black oxide screws. Also they carry a large selection of SS316 machine screws, nuts, washers, whatever. Also phosphor bronze, nylon, aluminum, brass, high strength steel, etc. The prices are relatively high, but might be lower than WM. Some sizes are sold in minimal quantities, so that can get you, but you can share with your buddies. They have CAD drawings of almost everything. Additionally, they list the specifications and material characteristics. I have used their materials throughout my career, and never had quality issue. If you can order through your boatyard or have a business address, sometimes you can receive shipments the next day, especially if you order early in the morning! Shipping is nearly always by UPS.
Check out their stock of rubber materials and adhesives. Great way to spend a rainy day just browsing the catalog.
 

tyree

New Member
Thanks for all the info! I just ordered my chainplate hardware from McMaster-Carr. great website! I was about to compare pricing at fastenal but could only find the bolts in a 100 degree countersink, the originals on my boat 382 #207 were 82 degree. total for bolts, nuts and washers was $80 before tax and shipping.
Screen Shot 2018-07-23 at 3.24.45 PM.png
 

stnick

lee nicholas
I have redone all my chain plates now with all new bolts and beding ! I just feel better. I used bytal under the plates and around the screws..
I also kept the buytal in my frig until i needed 5 inches of it ! On the inside i used a paper punch and used a one inch piece of bytal with a punch hole in the center. This i placed on every bolt coming thru from above, than the nut. The bytal acted like a stopper for any water.. Im in florida so cold bytal was easy to work with. once it got warm and sticky it was a night mare to work with !
I used fingernail polish on all the threads to tell me where the turnbuckles were. Seemed to work ok! McMaster- Carr is the real deal , I used them for my ice box rebuild. ! They made it easy !
 
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bob_mcdonald

robert mcdonald
Hey folks, thought I better post this in case other 38s are in a similar, but unknown state. I recently undertook to replace the chainplate bolts (that go through the deck) and rebed the plates, as part of preventative maintenance on my 384. I was happy to see no corrosion on the bolts, but had new replacements on hand, whic I installed. The unpleasant thing I discovered however, was cracking on 3 of the above-deck plates, on the tang portion at the 5/8" holes for the pins. I had new plates fabricated and installed them last week. One of the cracked tangs in particular would have resulted in a de-masting had it failed right through. Another thing for owners to check on our old girls.
 

mpearson

Mark Pearson
Staff member
Thanks for the info, Bob. So on the above-deck plates that were cracked, you could see the cracks visibly, without dye or anything?

I had a super good rig inspector give Zia a thorough inspection this summer. I'm hoping if they were visible he would have seen them.
 

jimcleary

James M. Cleary
Bob
If those cracks are visible to the eye, could you post a photo of one with a crack. I rebedded mine last spring and found no visual evidence of cracks in the tangs.

Jim
 

terry_thatcher

Terence Thatcher
I intend to replace shroud bolts this off season. Thanks for the warning about the deck plates. Maybe it is worth just replacing them too. Has anyone looked at or replaced the bolts on the stern for the back stays and forward for forestay? They are probably harder to deal with and they are certainly bigger bolts. On the other hand, since they are placed almost horizontally, they may be less likely to sit in water and corrode. Also, I had no idea that countersinks came in different angles. What tool can I use to measure that?
 

bob_mcdonald

robert mcdonald
Right ,cracks were visible without dye. not sure I can get a picture uploaded as internet spotty here in boatyard and I'm a little techno-challenged. I re-bedded the bolts top and bottom with butyl and the balance of the plate with life caulk ( polysulphide).
 

jimcleary

James M. Cleary
Robert
That looks like I've got another project to add to my spring list. I'm glad you posted the photos.

Jim
 
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