2001 B361 Chain Plate leak

[GDanko]

Shortly after completing the purchase, I noticed a drop of water under the starboard chain plate. I didn't have time to dig into the issue and possibly reseal the thru deck fitting. To be prepared for this maintenance, can anyone provide a short summary of steps I'll need to take to stop the leak?

I placed a tupperware bowl to capture future drips which should be minimal now that she's been wrapped. There are not any signs of water having sat in this spot so it's either been a very slow leak or it's new.
Thanks
jerry

 

[Stu Jackson]

Chainplates are an often neglected item of basic maintenance. You need to rebed the chainplate. While all manufacturers differ slightly, the concept is always the same: shrouds connect to a fitting that goes through the deck and then are connected to the hull somehow to distribute the load.

Here's how I did mine:

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

C34 mark 2 chain plates leaking - Chainplate flix

 

[GDanko]

Thank you Stu for reminding me of the correct sealant to use. I recently restored a Cape Dory and learned there are many places butyl tape works well and some not. The biggest decider is whether or not the butyl can be squeezed with the fasteners. For example if machine screws attach the item, the butyl will move but I errored installing bronze port trim rings that were held in with wood type screws - there wasn't enough bite from the screws to ooze the butyl out, resulting in stripped screws.

When I return to the vessel in the spring I'll be sure to carry along the butyl.

 

[RoyS]

If you have small sealant covers surrounding the chainplates and screwed to the deck, make certain that the securing screws are sound. If they do not bite into their respective holes your leak will never stop. Damaged screw holes can be repaired by overdrilling the holes and filling with a plug of GFlex. Also, be advised that this kind of deck leak can permit rain water to travel through the deck quite far from the point of entry and your catch bowl. This job requires patience and attention to detail to be successful.

 

[GDanko]

Thank you Roy. The boat is new to me but from the view in this picture, it looks like the cover is pushed down and covers the opening without any screws. My guess is a little gentle prying will allow me to lift it and expose the holes with the rods.

 

[Hollyberry]

I just redid both chainplates on our Bene... not the original fittings but a similar system.

..... My guess is a little gentle prying will allow me to lift it and expose the holes with the rods.

The 'cover' is held from below by two (almost hidden) screws in the overhead either side of the tie rod.


I did one side at a time, secured the mast with halyards, backed off the shrouds, disconnected and removed them from the deck fitting (you have original Beneteau setup so may have to totally unscrew the turnbuckle body from the bottom stud). There are two screws under the deck either side of the tie rod that hold the deck fitting in place.. The tie rod threads out up through that fitting, so maybe you don't need to remove that. Ours leaked around the 'ball' end of the tierod where some ancient Butyl had dried and cracked. We used Sikaflex to rebed the deck fittings and reseal the tie rod end. Fresh (quality) Butyl might do too..
You do have to thread the tie rod back into place so that may disturb the sealant somewhat; so I added sealant over the tie rod top between the shrouds after the tie rod was retightened.
Mark your turnbuckle settings AND tie rod thread position with masking tape first soas to get yourself back to the original settings.

Once one side was complete, we secured the other with halyards and repeated. Not a bad job, completed in about half a day.

If you are primarily leaking around the tie rod fitting the it may not be necessary to remove the deck fitting, but if you're going to all that trouble you may as well rebed that as well.

You can see the difference between fittings below but the basic physical arrangement is very similar.

 

[GDanko]

Excellent work documenting the repair; I should be able to do as suggested. The PO of 9 years, never removed the mast but the boat is dry (almost) so I'm guessing he's done this in the past. Thank you!

 

[joker460]

Excellent work documenting the repair; I should be able to do as suggested. The PO of 9 years, never removed the mast but the boat is dry (almost) so I'm guessing he's done this in the past. Thank you!

I came across these pictures where that connection you showed, failed.
It's a Bene.

.

 

[GDanko]

Ouch! Any background info or forensics on the cause?

 

[Hollyberry]

I came across these pictures where that connection you showed, failed.
It's a Bene.
View attachment 211231 .

Ouch!... good find....

Looks like severe corrosion of the deck fitting itself..Must have pulled free of the tie rod ball too, I expect, unless all that looks just as bad!! Somebody wasn't paying attention!

I've heard of a corrosion failure of the crosspin (at the bottom of the tierod) on a B 40.7 in the caribbean.. due to a long ignored deck leak at the chainplate.

 

[joker460]

If I remember the thread correctly, he was looking to sue the surveyor that passed that fitting. It's a Beneteau 350 or 351 .

Here is a simular thread that you might be interested in on this site. Beneteau 361 2001 Lower Chainplates replacing damaged rubber seal

 

[GDanko]

Interesting discussion; Conclusion - there's not a "rubber seal", just sealant which some suggest to use 3M 4200 while others use butyl.

Use halyards to hold mast, take pictures, mark turnbuckles, complete removal, clean, analyze, re-assemble with a sealant, adjust to previous turnbuckle setting for initial ball park setup. Repeat on the other side, tune rigging.

 

[jssailem]

Nice clean repair and procedure @Hollyberry .

No matter the brand, all boats need to be inspected for stainless steel corrosion. It is an annual task on my boat. Crevice and pit corrosion is the secret destructive operator on Stainless Steel.

The material looks fine on the outside. It is where water sits on the stainless, in the cracks, little surface pits, and places hidden with out oxygen that corrodes. Like a cancer it eats away at the part from the inside.



These are a few examples.

The through deck placement of chainplates and the swage fittings of shrouds are common suspects on sailboats. It is up-to the owners to be vigilant and protect our boats.

If you remove your mast for the winter, it is a great time to inspect all of the stainless steel fittings and parts attached to the mast. While they look like forever hardware they are not.

 

[GDanko]

Although our recently acquired B361 has always been in fresh water and pulled each winter, the PO never removed the mast in the 9 years he owned her. And, the pre-purchase surveyor didn't inspect any standing rigging above the deck so I'll be searching for a northern Michigan rigger to go aloft this spring to raise my comfort level.

 

[jssailem]

Does the mast winter in place? Are you a DIY guy or rely on the experts?

 

[Hollyberry]

Interesting discussion; Conclusion - there's not a "rubber seal", just sealant which some suggest to use 3M 4200 while others use butyl.

Use halyards to hold mast, take pictures, mark turnbuckles, complete removal, clean, analyze, re-assemble with a sealant, adjust to previous turnbuckle setting for initial ball park setup. Repeat on the other side, tune rigging.

One other thing I did for peace of mind was to do the dock-side shroud first, then spun the boat around so that the second side was at the dock as well. More options for accessing and (slightly) lower odds of dropping something in the drink.

To support jssailem's point, unlike the Beneteau deck fitting (chromed bronze) our replacements are solid SS. Even so, you can clearly see below where the tie rod leak sat (and eventually traveled) to the 'downhill' retaining bolt and dripped into the boat there. Significant effect on the SS in that area.

Had this been a salt water leak and the original bronze fitting it's not hard to envision serious degradation of the material leading to the failure shown above. Could be why we have these new, improved custom SS bits.....

 

[GDanko]

Does the mast winter in place? Are you a DIY guy or rely on the experts?

Yes, and usually yes. The mast was never removed by the PO owner (9 yrs) and I've yet to remove it. I try to learn as much as possible and then attempt to accomplish the task. Unfortunately I'm not very good at throwing in the towel after starting though.

 

[jssailem]

1. I try to learn as much as possible and then attempt to accomplish the task.
2. Unfortunately I'm not very good at throwing in the towel after starting though.

Item 1... I like it. It is a trait I also use to avoid unnecessary tasks.
Item 2... I have never liked throwing in the towel. I have been known to call an audible and get second opinions. Even used the "Call a friend/SBO member" for insight. When all ideas exhausted... Read the manual and/or call a specialist is always an option.

 

[Mechone]

First its a Beneteau chain plate , you cannot use Butyl tape as some have suggested ,use 3m 4200 . Take the mast down undo 2 bolts on ceiling , undo rod marking it to go back to correct length . The complete assembly can now be removed. I can tell you do not leave it leaking where the rod goes thru is about 2 inch thick balsa core, which you must keep water out of. A good practise is to coat the core with west epoxy to eliminate any water getting into it. You must seal the bottom and fill the top with of chainplate 4200 or you can cause the top ball and socket to rot. I actually machined delrin plugs that press in and are held by the 4200 ,this prevents any water ever getting down onto the ball and socket

 

[GDanko]

Mechone, do you have delrin plugs available for others? I'd gladly buy them if so.

"must seal the bottom" refers to sealing where the big fitting sits on the deck?