Fixing the gas tank problem
- Thread starter clayhubler
- Start date
You should be OK as long as the trailer bunks extend slightly beyond the transom, and well forward of the area you are removing. Take a straight edge and double check to be sure.
The wider the bunk boards the better. If there appeared to be any distortion before putting new core in, then I would jack up the boat by the transom, and slide 3/4" cheap plywood under each side up to a bit further tan where the cut outs started.
Another issue, is will there be distortion when you are kneeling in the cockpit. You may want to put some 2 x a 8 boards on top to kneel on. which go edge to edge and contact the area on the inside of the hull over the trailer bunks.
The wider the bunk boards the better. If there appeared to be any distortion before putting new core in, then I would jack up the boat by the transom, and slide 3/4" cheap plywood under each side up to a bit further tan where the cut outs started.
Another issue, is will there be distortion when you are kneeling in the cockpit. You may want to put some 2 x a 8 boards on top to kneel on. which go edge to edge and contact the area on the inside of the hull over the trailer bunks.
clayhubler
Member
That sound like an excellent suggestion, will do
clayhubler
Member
Okay, back at it. I've got to say that I am pretty disappointed with the construction methods used by the factory at this point...
As I've been working on this I've been considering how to put it back together. Specifically how to laminate the balsa with the glass and how to make sure I have no voids. I don't imagine it is easy to fill all the kerfs in the balsa with epoxy, and along the edges where the balsa meets the side of the hull. I now can see that the factory did not bother with these details.
I have heard that the water doesn't migrate very far because the balsa is end grain, so it doesn't have the ability to wick away from the access point. This is not true:
Large voids in the sides along the edges of the balsa allowing water to flow back and forth:
This side was dry, but the void is there also:
It looks like the boat sat in the water with a list at some point in the past. The port side is way worse than starboard:
You can see that I've cut a huge area out, but it's obvious that the wet and rotten wood extends much farther forward still. I'm worried that with the kerfs in the balsa wide open and the voids on the side that the coring may be wet all the way to the forward bulkhead.
Please correct me if I'm wrong but there is no balsa under the v-berth? Only pour foam?
Also, is the balsa in the transom sealed from the balsa in the hull? I'm a little worried that the lower part of the transom is going to be rotten as well, especially on the port side. I'm hoping they are isolated. The part on the transom that was rotten looks to me like it got that way because of poorly sealed engine mounting bolts.
As I've been working on this I've been considering how to put it back together. Specifically how to laminate the balsa with the glass and how to make sure I have no voids. I don't imagine it is easy to fill all the kerfs in the balsa with epoxy, and along the edges where the balsa meets the side of the hull. I now can see that the factory did not bother with these details.
I have heard that the water doesn't migrate very far because the balsa is end grain, so it doesn't have the ability to wick away from the access point. This is not true:
Large voids in the sides along the edges of the balsa allowing water to flow back and forth:
This side was dry, but the void is there also:
It looks like the boat sat in the water with a list at some point in the past. The port side is way worse than starboard:
You can see that I've cut a huge area out, but it's obvious that the wet and rotten wood extends much farther forward still. I'm worried that with the kerfs in the balsa wide open and the voids on the side that the coring may be wet all the way to the forward bulkhead.
Please correct me if I'm wrong but there is no balsa under the v-berth? Only pour foam?
Also, is the balsa in the transom sealed from the balsa in the hull? I'm a little worried that the lower part of the transom is going to be rotten as well, especially on the port side. I'm hoping they are isolated. The part on the transom that was rotten looks to me like it got that way because of poorly sealed engine mounting bolts.
clayhubler
Member
Here is where I am at now:
I wonder is there an alternative core I could use for the repair? I'm not really a fan of this balsa right now. I have dug saturated pour foam out of boats before though too, and it was supposedly 'closed cell'
I wonder is there an alternative core I could use for the repair? I'm not really a fan of this balsa right now. I have dug saturated pour foam out of boats before though too, and it was supposedly 'closed cell'
I believe you are doing well--and probably would do this repair before moving forward. This will allow stability of the hull bottom.
You are correct that once delimitation begins, the water flows along the surface, or in cuts (kerfs) and can move into a much more extensive area. There aren't really "totally closed cell foams...
Balsa has a number of properties which are in its favor, and that is why it is still being used today. It has good shear and compression strength. The foams and the hex cell materials lack a little in these departments. They certainly can be up used Once the balsa is done right, and not penetrated it is a great material. I was involved with boats built with balsa core (plank) which are now over 50 years old, and the core is still fine, despite several circumnavigations, groundings etc. The secret is that no core penetrations, without the proper sealing.
The only C Dory I can speak to about the transom and bottom was my 2003 25' C Dory I document in the photos and repair, that they were sealed off. They should be because of the way the boat is built. You don't want balsa to balsa at at hard and structural edge....
Yes, boats are all built to some price point..and weight point etc. One of the around the World racers (actually several) leaders, is involved with do a major hull delimitation repair on a a multi million dollar 60' boat...under sail, alone. Sort of like rebuilding your space craft as you get ready to land on the moon....
Thank y ou for documenting the great work you are doing!
You are correct that once delimitation begins, the water flows along the surface, or in cuts (kerfs) and can move into a much more extensive area. There aren't really "totally closed cell foams...
Balsa has a number of properties which are in its favor, and that is why it is still being used today. It has good shear and compression strength. The foams and the hex cell materials lack a little in these departments. They certainly can be up used Once the balsa is done right, and not penetrated it is a great material. I was involved with boats built with balsa core (plank) which are now over 50 years old, and the core is still fine, despite several circumnavigations, groundings etc. The secret is that no core penetrations, without the proper sealing.
The only C Dory I can speak to about the transom and bottom was my 2003 25' C Dory I document in the photos and repair, that they were sealed off. They should be because of the way the boat is built. You don't want balsa to balsa at at hard and structural edge....
Yes, boats are all built to some price point..and weight point etc. One of the around the World racers (actually several) leaders, is involved with do a major hull delimitation repair on a a multi million dollar 60' boat...under sail, alone. Sort of like rebuilding your space craft as you get ready to land on the moon....
Thank y ou for documenting the great work you are doing!
To answer your question about wood core under v-berth, go look into my photo album. I had to open up my v-berth because of a water/gas leek problem and decided to remove all the foam for extra storage. In a couple picture you can kind of see under my tools that the wood core stop about 4-6 inches past the bulkhead. let me know if you need more accurate measurement, but I don’t think you will need to go that far.
I just posted a thread about cores, Balsa vs Foam, proper technique etc with links to West Systems 396 page PDF book onus of epoxy. (not an endorsement for West Systems, although that is what I use currently).
I posted a new thread rather than on this particular thread, because it has relevance to all balsa core repair.
I posted a new thread rather than on this particular thread, because it has relevance to all balsa core repair.