I just replaced the pivot bolt for my centerboard (I have a 17' sailing dinghy), and I put new neoprene washers on both sides of the bolt, and I'm still getting a little water leaking in. How do I seal it? Would 3M 4200 work on the neoprene?
Sealing a rubber washer for centerboard bolt
- Thread starter barney17
- Start date
4200 would be my first choice. LocTite sells a knockoff of 4200 in a caulk tube that's stood the test of time
It would be helpful to see a photo or two of the problem area. Is the pivot bolt intended to be fixed, i.e., not rotating? Is it above the waterline or below?
Soft washers made from rubber, nitrile or some other rubbery material will deform and leak if tightened too much. Adding an sealant/adhesive like 4200 might work if the bolt doesn't rotate, however as soon as it rotates it will break the seal and leak again.
Soft washers made from rubber, nitrile or some other rubbery material will deform and leak if tightened too much. Adding an sealant/adhesive like 4200 might work if the bolt doesn't rotate, however as soon as it rotates it will break the seal and leak again.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,942
I do not know the details of the Barnegat 17. There have been many dinghy daysailers built through the years. In the late 60s and 70s, it was a popular boat to build and sail. The Barnegat 17 was a class boat when used for racing. There were rules that, when followed, allowed the boat to participate in class races.
Here is a link to the class race rules.
Of note was the following regarding the centerboard and trunk:
Here is a link to the class race rules.
Of note was the following regarding the centerboard and trunk:
The bottom, top, and forward edges of the board shall be straight, and the after edge shall be an arc of a circle. ,
(3) Centerboard pin shall be 3/8" in diameter,
(4) The centerboard may not be lowered to allow the upper edge of the centerboard to be lower than the height of the trunk cap. A stop on the centerboard must be affixed to ensure this.
(5) Centerboard flaps or gaskets shall not be permitted owner to race the boat in class races.
If racing is not in your future, then you are able to create just about anything you desire to make your boat sail the way you desire. It would help us creative boat owners who work on older boats, to see some images of the problem you have and how you have tried to resolve it.
I would be concerned that many types of rubber would dry out after a few years
Perhaps the rules are referring to a seal/flap where the hull meets the trunk? My 420 had that. I kept splashing to a minimum and reduced drag
Thank you all for the help! I really appreciate it. Here are some pictures. You can see the bolt in the bottom left of the centerboard, this is the pivot bolt so it's going into the water (the water is on the inside of the centerboard cavity). The bolt doesn't need to rotate, the centerboard can spin around it. I don't know if this area is wood or fiberglass, I assume 4200 is fine with either, I just wasn't sure if it was good to use against a rubber washer.
Regarding the rubber washer, I saw that there was an old rubber washer there when I got the boat, so I assumed it was a good idea. And what type of rubber would anyone suggest? Or not rubber at all? I just assumed neoprene was good for water exposure (and like a wetsuit, this will get wet but mostly hang dry since the boat lives on the side of my house).
Also I tested the new washers without any sealant and it did stop a LOT of the leaking (compared to an old boat with worn old washers). But it still dribbled in pretty steadily.
Also worth noting that the bolt itself is cocked - it's not perfectly parallel along the beam like it should be. So probably adding to a lack of sealing there. It's all old.
Regarding the rubber washer, I saw that there was an old rubber washer there when I got the boat, so I assumed it was a good idea. And what type of rubber would anyone suggest? Or not rubber at all? I just assumed neoprene was good for water exposure (and like a wetsuit, this will get wet but mostly hang dry since the boat lives on the side of my house).
Also I tested the new washers without any sealant and it did stop a LOT of the leaking (compared to an old boat with worn old washers). But it still dribbled in pretty steadily.
Also worth noting that the bolt itself is cocked - it's not perfectly parallel along the beam like it should be. So probably adding to a lack of sealing there. It's all old.
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jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,942
The images help.
I now have a clearer picture of what you are doing.
I understand that the metal center board is sitting on your bolt. The hole in the centerboard is about the diameter of the bolt.
As the centerboard rotates and bangs about in the centerboard trunk, the bolt is moving (creating an opportunity for water seepage onto the deck of the boat). At the same time, the center board is chafing on the bolt, wearing the bolt down to failure.
It appears that the bolt is held in place by pieces of painted wood.
Have I properly described the images?
I now have a clearer picture of what you are doing.
I understand that the metal center board is sitting on your bolt. The hole in the centerboard is about the diameter of the bolt.
As the centerboard rotates and bangs about in the centerboard trunk, the bolt is moving (creating an opportunity for water seepage onto the deck of the boat). At the same time, the center board is chafing on the bolt, wearing the bolt down to failure.
It appears that the bolt is held in place by pieces of painted wood.
Have I properly described the images?
Thank you for the photos, very helpful.
Neoprene is probably too soft. There is a gasket product BUNA-N that might be a better choice. Do some research on BUNA-A washers. This is the material many O-rings are made of, so it is firm and resilient. It is designed to be under pressure and not distort.
If the bolt does not align, it will be very difficult to get a good seal no matter what washers are used. I would suspect one of the bolt holes has gone oval or it has been repaired in the past with the hole having been drilled cockeyed. The solution is to drop the CB and inspect. Depending on the CB trunk construction it may be a wood working project or a fiberglass project. It won't be an expensive repair (unless the CB trunk is seriously rotted) but it may be bit fiddly and time consuming. If the boat is in otherwise decent condition, it's a repair worth doing. It will also answer the question about the trunk material. If it is all wood, then water is definitely bad for it.
Good luck.
jssailem - yes that's all accurate
dlochner - thanks I'll check out those washers.
Could I try the 4200 under the washers and see how that seals? The leak is slow enough that I feel like I just need a little more sealant. But I understand what you mean about maybe needing the bigger repair.
dlochner - thanks I'll check out those washers.
Could I try the 4200 under the washers and see how that seals? The leak is slow enough that I feel like I just need a little more sealant. But I understand what you mean about maybe needing the bigger repair.
If you don't mind cleaning up the mess later, go ahead.
We are still in the world of ifs. If the trunk is solid fiberglass, there's no damage will be done to the CB trunk. On the other hand, if the trunk is plywood or glass covered plywood and water is getting into the wooden core then there are big problems ahead.
There's no much fun sailing going on in Barnegat Bay for the next few months. This makes it a prime time to investigate the trunk construction and if a repair is needed. Is there a class association for the boat? Or a group racing them? Owners of niche boats are usually really supportive of new boat owners and will give freely of advice and well earned experience. Its in their interests to keep as many boats floating as possible.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,942
Sure, why not? The 4200 is not rigid, there is flex.
I would look into something of a hardened material, rather than the bolt.
If you are looking for a more permanent fix, examine the possibility of a plate on each side of the trunk that will support a pin that fits through the centerboard. Perhaps a bushing through the centerboard to reduce the chafe and make the centerboard rotate smoothly
I would look into something of a hardened material, rather than the bolt.
If you are looking for a more permanent fix, examine the possibility of a plate on each side of the trunk that will support a pin that fits through the centerboard. Perhaps a bushing through the centerboard to reduce the chafe and make the centerboard rotate smoothly
Where is the leak? Is it coming through under the bolt head, or is it at the edges of the washer? If the latter a sealant or different washer material might help. If it‘s around the bolt head a washer with a slightly smaller center diameter than the bolt might hug the bolt tightly enough to be effective.