CSY Owners Forum

General Category => Hull and Rig => Topic started by: Soggy Geek on August 18, 2017, 09:27:53 PM

Title: External Round Chainplates Design
Post by: Soggy Geek on August 18, 2017, 09:27:53 PM
We occasionally get requests for the details of the round chainplates we put on Soggy Paws.  See our account of upgrading our chainplates to an external round one, and why we chose that over just replacing the original internal chainplates, here:  http://svsoggypaws.com/rig.htm#Chainplates

I just stumbled into a drawing file that someone else (s/v Imagine) made, that I downloaded a few years ago.  Their website is no longer operational, but fortunately I saved a copy.  I am not sure whether this info is in the CSY Dropbox or not, but here is the PDF and the DXF file.

I am not absolutely positive this is identical to Ron Sheridan's original design--you'd have to verify that yourself.

Sherry
Title: Re: External Round Chainplates Design
Post by: Soggy Geek on August 18, 2017, 09:35:13 PM
And a link to Ron Sheridan's posts on this subject.

http://csysailboats.blogspot.com/search/label/Chain%20Plates

Sherry
Title: Re: External Round Chainplates Design
Post by: LittleSkipper on August 21, 2017, 09:08:47 AM
Soggy Geek,

Thank you very much.  This is just what I was looking for.  Our current Chain Plates are the original type and were renewed 15 or 16 years ago.  I am not sure we will be changing them soon but most likely while we own Contessa CSY 44 ketch. 

What is the forum's opinion?  The boat is in Grenada and we hope to sail her back to Annapolis next winter & spring.  Considering the seas and weather that time of year would you recommend renewing the chain plates sooner?   I am planning to get a professional opinion from a close friend and previous owner operator of Chesapeake Rigging Tom W.   in September.
Title: Re: External Round Chainplates Design
Post by: LittleSkipper on August 21, 2017, 10:31:07 AM
Hi Soggy Geek,

This is an FYI:   I was having difficulty loading this file "Imagine Chainplates Drawing.DXF" into LibreCAD that you attached above.  I took a look at it with "notepad" and found that its contents is a "HTTP Error 404 - File or directory not found."

But the pdf files are great!

Title: Re: External Round Chainplates Design
Post by: Doug Vaughn on August 21, 2017, 03:26:37 PM
Contemplating the chainplate replacement project. Has anyone left the internal plates in place and used those for intermediate backing plates for the new ones? Then, adding new secondary backing plates.  Seems this would add significant strength to the connection point.
Doug
Title: Re: External Round Chainplates Design
Post by: Matthew Balch on August 22, 2017, 09:22:06 AM
Hi Martin,  I would think that chainplates should last at least 25 years.  Yours have already been replaced so they could go less or longer depending on how much the boat was used, where it was used, how well maintained, the quality of the materials & design, etc.  They are easy to give a cursory inspection, and as long as you do not see an issue, they are probably just fine for a number of years, in my opinion.  Mine were replaced about 10 years ago and they are still perfect.  Matthew
Title: Re: External Round Chainplates Design
Post by: Soggy Geek on August 25, 2017, 01:42:31 AM
Little Skipper, sorry the DXF file is no good, but hopefully the PDF will give you what you need.  I confess I never opened that file--just downloaded it from someone else's website, and that website is now gone.

Sherry
Title: Re: External Round Chainplates Design
Post by: LittleSkipper on September 02, 2017, 07:12:56 AM
Soggy Geek,
Sorry for my late response.  No worries; the effort was much appreciated as were all the other files.
Title: Re: External Round Chainplates Design
Post by: LittleSkipper on September 02, 2017, 07:29:37 AM
Hi Matthew,

Thank you for your positive response.  I appreciate your thoughts. Contessa was not sailed too hard over the past 9 yrs or so.  I will be visiting Contessa with a USB borescope 5.5 mm and dental tools to dig out the caulking.  I hope I can get a good look a the hidden parts.  From what I have read here and other sources, it is those parts you can't see or more importantly does not get air/oxygen that will in time cause the problems. 
Title: Re: External Round Chainplates Design
Post by: LittleSkipper on December 11, 2017, 03:09:34 PM
I recently worked with Erik at DIGITAL FABRICATION RESIDENCY.  I contracted with Erik to produced CAD files for external chain-plates for the CSY44.  These are the 10" round external plates but look a little different than what has been used on Soggy Paws and Beaujolais.  I put them in the Drop box because they are to big to attach here. Look into Dropbox\CSY Info\CSY 44\Chain Plates

Also, I have quoted waterjet cut 316 SS chain-plates from Alaskan Copper.
1/2” would be $137.35 ea.
3/8 would be $108.94 ea.
2 - 3 days to water jet
This is only waterjet cutting no flathead counter sink,  radius on the edge, polishing, or bend.
Don't forget to add shipping.  That will cost me another $600 from Seattle to Grenada.
Title: Re: External Round Chainplates Design
Post by: Doug Vaughn on December 21, 2017, 06:09:38 PM
Little Skipper, Thank you for the addition of the chainplate drawings. I am about to undertake the project and have a quote from Fowler Metals in West Palm Beach of $1400 which includes 1/2" 316 SS cut with water jet including the square holes for carriage bolts and bending with a rounding of all edges. The only item not included is polishing which I will do. I do see you have a 10" diameter with a nice curving shape up to the top in 1/2" ss. The Imagine drawings show an 8" diameter with 3/8" ss plate. I had them cut a test plate out of 18ga. material just to get an idea. I'll be going with the 10" diam.
Keep us posted on your progress, I'll do the same.
Doug
Title: Re: External Round Chainplates Design
Post by: svsurprise on December 25, 2017, 08:34:47 AM
Good Morning and Merry Christmas,
A simple question for those who have undertaken the job of upgrading their chainplates.  Is it possible to remove the original chainplates without removing the rub rail?  Are the bolt heads captive or should I expect them to rotate while removing the nuts from inside the hull.
Thanks,
Don
Title: Re: External Round Chainplates Design
Post by: MY TIME on December 25, 2017, 10:22:12 AM
Unfortunately the answer is no. The bronze rub rail has to be removed first. Then the bolt heads which are a slotted screw head have to be dug out, as they are buried in polyester resin. Also the top bolt is behind the teak trim just below the teak cap rail.
Donald Stengel hull#30 44WO
Title: Re: External Round Chainplates Design
Post by: LittleSkipper on January 28, 2018, 11:12:25 AM
Hi Doug,  I am glad you are able to use the chain-plate files I put online.  Unfortunately, we won't be using them. Not because I don't want to but because we are running out of time.  We decided to use the local skills which means our chain-plates will be external long strap type which are simpler, cheaper and quicker to fabricate.  Ours will be about 22"x4" long for the cap shroud and aft lowers and intermediate so they will extend below the rub-rail. The forward lower will be about 2-1/2" wide and a bit shorter.

Regarding the time element: Contessa is in Grenada and we hope to get her back to Annapolis before Hurricane season.  We are heading to the boat mid Feb. I plan to add photos here of the completed project.
Title: Re: External Round Chainplates Design
Post by: Moonstar 44 on May 15, 2019, 04:02:18 AM
Any pictures yet?
I have a csy 44 walkover and need to do the chainplates as well.
Title: Re: External Round Chainplates Design
Post by: Soggy Geek on May 15, 2019, 05:19:31 PM
Pictures of the Soggy Paws job here:

http://svsoggypaws.com/csy/rig.htm#Chainplates
Title: Re: External Round Chainplates Design
Post by: Soggy Geek on May 15, 2019, 05:25:14 PM
And Beaujolais helpful detailed writeup is here:

http://svsoggypaws.com/csy/beaujolaischainplates.htm
Title: Re: External Round Chainplates Design, Original drawing
Post by: Ron Sheridan on August 26, 2019, 01:25:04 PM
Hello gang,
Have been off this site for years but checking back in saw some discussion on the Round Chain Plate design I had come up with in the latter 90's.  My design, was a take off of a design by Tillerson Pearson and Steve Dashew for the manufacture 54'-62' Deerfoot Yachts. You can see their design (10 bolts) in the Dashew's Cruising Encyclopedia page 582. For manufacturing it made a lot of sense, as you could make All chain plates the same and just rotate the tang in the direction needed.  Installation was easy, just drill and insert the center bolt first, the rotate the tang in the direction of the rigging wire, or attach it.  Drill the remaining holes, insert bolts and so on. Easy.  CSY used 3/8" tang material (304 SS) welded to a 1/4" triangular backing plate, with 6 bolts.  I used 1/2" (316 grade SS) (no welds needed and 8  "Counter Sunk" headed bolts also 316 grade.  Plated cut on a C&C machine, but later ones were made at a machine shop locally for other owners and looked perfect as well. Note, countersinking the heads, offered crevice corrosion protection.  Many Hex Head bolts used on CSY's failed, heads snapping off because water/moisture could gain access under the head and over time, crevice corrosion cause the stainless to fail.
Here's a few photos from 2000/2001.
 Note, back in the day, I payed about $300/Plate for material, cutting, final polishing(I did it up to 600 grit).  the bolts alone back then were $9.69 each plus Aircraft 316 Nylock nuts and 1/2" large flat washers for the interior.  I ordered 100 as my Pilothouse was a ketch requiring more plates/bolts.
Important I feel is that, without the ability for heavier material used and double width tangs (4" double vs 2" single) and 1/2 thick material vs 3/8's as well as 8 bolts rather than 6, the plates should last 1/2 century! I feel reason this method makes Chain Plates totally trustworthy for many decades....many.
The limit here on 'file size' prohibits me from including a the diagram which is 178 ks' vs 158 allowed, so I'll post a few of these on my blog site for those interested.https://memoryrose.blogspot.com/search/label/Chain%20Plates (https://memoryrose.blogspot.com/search/label/Chain%20Plates)
Hope this helps anyone engaged in this project.
Title: Re: External Round Chainplates Design
Post by: Ron Sheridan on August 26, 2019, 01:29:47 PM
...click any photo for a slightly larger version if needed.