Looking at the 5th photo from the top, it appears to me that the side of the CB trunk is bowed out a little, which indicates (to my inexperienced eyes) that you have a water infiltration problem in the plywood and need to bite the bullet and rebuild it. But it may be just my eyes, as with my latest glasses my round frying pan suddenly appears oval....
I'm concerned that over tightening the CB bolt will squeeze in the trunk sides, so you will not be able to stop the leak that way. One way I have done this is to start with a pipe flange on each side of the trunk. This can be screwed down, with plenty of bedding compound under it (My preference is for Dolphinite). Of course you would use brass or bronze here. I see you have only 3/8" sides on the trunk, so you would have to use short screws. Could be reenforced by drilling 4 more screw holes, giving you 8 for each flange. These could be countersunk for FH screws, or just use round head screws.
Into each pipe flange, screw in a short nipple, threaded both ends. Use pipe compound to prevent leaks through the pipe fittings. Insert your centerboard bolt, then screw on pipe caps to the ends of the pipe nipples. Should take care of your leaks. Only problem is avoiding stubbed toes with these protuberances. The CB bolt can be free floating; no need for it to be a tight fit.
Old School fix for this....Get a length of cotton wicking, dredge it in boat paint and wrap the bolt between the washer(s) and the trunk. Tighten til you see paint start to squeeze out. It has been working on our Penobscot 14 for 7 years now. http://smallboatrestoration.blogspot.com/p/penobscot-14-st-jacques.html
Get in touch with the Coots. Several of us live in and near Eugene and would be glad to give you some help. We're having our Wednesday lunch at Richardson Park tomorrow (Oct. 2nd) at 1:00 if you'd like to meet us:
It is probably time to completely rip out and rebuild the trunk. Next time, I would oversize the pivot holes and then completely fill with epoxy before putting a coating of epoxy over the entire trunk. Then I would drill the proper sized hole for the pivot. This ensures that no water can ever come in contact with the plywood.
Something I am going to do to my GP14, I am about to cut some mahogany donuts to fit over the pivot bolt. Once they are glued and screwed to the case, I have a pair of bronze deck fill caps that I will be sealing to the case over the bolts. This allows access when necessary, but keeps any and all drips from reaching the inside of the boat. Obviously, I will need to periodically open them to keep any standing water from causing rot.
I also think that if you do not need to often open the top of the trunk, some flexible sealant used between the trunk and cap may be better than a gasket. This will allow you to remove it on occasion. If you are adverse to this, it may be time to find a rubber o-ring you can press into service as a better gasket. The Pelican Case company sells replacement o-rings for their waterproof flight cases that can be made to work.
I have never had a centerboard trunk that did not find a way to leak. The pivot on one got the plumbing hardware approach. Another leaked through the haulup line fitting. Another, in my younger, more ignorant days leaked at the base of the trunk. There have been others.
I have found that only way to avoid leakage is not to have a hole in the boat. That is why the Whitehall is being fitted with a leeboard. With a relatively narrow boat, it is not difficult to sail the boat level. It is even easier with a beamier boat but requires more mobility.
I experienced this about 30 years ago with my Drascombe Lugger and i used a variation of Kent’s solution. I took three cotton balls and twisted them into a yarn. Then I used a small flat screwdriver to tap the cotton in around the centerboard pivot. I didn’t use any paint or glue, just cotton.
I have yet to replace that cotton and I’ve never had another leak. Oh, and by the way, my trunk is made of plywood.
Im dealing with this on my Potter 15, that Ive been refurbishing over the past year. It spent it’s first night in the water, Fern Ridge, and the next morning when I hauled it a good 4-5 gallons poured out the bilge drain. I located the leak at the swing keel pivot. My keel pivot was a stainless bolt, fiberglassed over. Not sure if that was a factory install or done later. Ive cleaned up the area and Im trying to decide how to proceed. The bolt was slightly bent but the area around it was pretty rough…
Looking at the 5th photo from the top, it appears to me that the side of the CB trunk is bowed out a little, which indicates (to my inexperienced eyes) that you have a water infiltration problem in the plywood and need to bite the bullet and rebuild it. But it may be just my eyes, as with my latest glasses my round frying pan suddenly appears oval....
I'm concerned that over tightening the CB bolt will squeeze in the trunk sides, so you will not be able to stop the leak that way. One way I have done this is to start with a pipe flange on each side of the trunk. This can be screwed down, with plenty of bedding compound under it (My preference is for Dolphinite). Of course you would use brass or bronze here. I see you have only 3/8" sides on the trunk, so you would have to use short screws. Could be reenforced by drilling 4 more screw holes, giving you 8 for each flange. These could be countersunk for FH screws, or just use round head screws.
Into each pipe flange, screw in a short nipple, threaded both ends. Use pipe compound to prevent leaks through the pipe fittings. Insert your centerboard bolt, then screw on pipe caps to the ends of the pipe nipples. Should take care of your leaks. Only problem is avoiding stubbed toes with these protuberances. The CB bolt can be free floating; no need for it to be a tight fit.
Old School fix for this....Get a length of cotton wicking, dredge it in boat paint and wrap the bolt between the washer(s) and the trunk. Tighten til you see paint start to squeeze out. It has been working on our Penobscot 14 for 7 years now. http://smallboatrestoration.blogspot.com/p/penobscot-14-st-jacques.html
Get in touch with the Coots. Several of us live in and near Eugene and would be glad to give you some help. We're having our Wednesday lunch at Richardson Park tomorrow (Oct. 2nd) at 1:00 if you'd like to meet us:
http://www.coots.org/
https://oregoncoots.groups.io/g/main/
It is probably time to completely rip out and rebuild the trunk. Next time, I would oversize the pivot holes and then completely fill with epoxy before putting a coating of epoxy over the entire trunk. Then I would drill the proper sized hole for the pivot. This ensures that no water can ever come in contact with the plywood.
Something I am going to do to my GP14, I am about to cut some mahogany donuts to fit over the pivot bolt. Once they are glued and screwed to the case, I have a pair of bronze deck fill caps that I will be sealing to the case over the bolts. This allows access when necessary, but keeps any and all drips from reaching the inside of the boat. Obviously, I will need to periodically open them to keep any standing water from causing rot.
I also think that if you do not need to often open the top of the trunk, some flexible sealant used between the trunk and cap may be better than a gasket. This will allow you to remove it on occasion. If you are adverse to this, it may be time to find a rubber o-ring you can press into service as a better gasket. The Pelican Case company sells replacement o-rings for their waterproof flight cases that can be made to work.
I have never had a centerboard trunk that did not find a way to leak. The pivot on one got the plumbing hardware approach. Another leaked through the haulup line fitting. Another, in my younger, more ignorant days leaked at the base of the trunk. There have been others.
I have found that only way to avoid leakage is not to have a hole in the boat. That is why the Whitehall is being fitted with a leeboard. With a relatively narrow boat, it is not difficult to sail the boat level. It is even easier with a beamier boat but requires more mobility.
I experienced this about 30 years ago with my Drascombe Lugger and i used a variation of Kent’s solution. I took three cotton balls and twisted them into a yarn. Then I used a small flat screwdriver to tap the cotton in around the centerboard pivot. I didn’t use any paint or glue, just cotton.
I have yet to replace that cotton and I’ve never had another leak. Oh, and by the way, my trunk is made of plywood.
Good Luck!
Scott
Im dealing with this on my Potter 15, that Ive been refurbishing over the past year. It spent it’s first night in the water, Fern Ridge, and the next morning when I hauled it a good 4-5 gallons poured out the bilge drain. I located the leak at the swing keel pivot. My keel pivot was a stainless bolt, fiberglassed over. Not sure if that was a factory install or done later. Ive cleaned up the area and Im trying to decide how to proceed. The bolt was slightly bent but the area around it was pretty rough…