Boat is new to us. Got her for a project boat price and everything has gone better than expected up to this point. However, long-term small leaks at the chainplates have impacted the integrity of the bulkheads. Too bad because the previous owner spent a lot of money not too long ago replacing them and the compression post (post is in fine shape). Ten dollars worth of 3M 4200 and an hour's worth of work would have prevented this. Anyway, winter plan is to replace both the port and starboard bulkheads. I have some woodworking skills (furniture building is a hobby) so not too intimidated but would appreciate any tips and pointers anyone may have for this particular project on this particular boat (or similar boat). A video link would be even better, if one exists. I searched the forums pretty extensively and kind of surprised not to find anything directly on point. Any input would be greatly appreciated. Thanks all.
Bulkhead replacement on Hunter 33.5
- Thread starter dbreedlove
- Start date
I replaced the entire interior of a Coronado 23.
The difficult thing for me was the fact that the full sized bulkhead would not fit through the companionway hatch. So I had to either remove the deck or build the bulkhead in two pieces and reassemble it once inside. I chose the later option. If you have the seam run vertically, (i.e. you build it as a left and right piece) you can create a "brest plate" at the top that effectivly hides the seam and also acts to add structuraly integrity. That is not what I did (see thumbnail below) so I ended up hiding my seam with exterior grade carpet.
The difficult thing for me was the fact that the full sized bulkhead would not fit through the companionway hatch. So I had to either remove the deck or build the bulkhead in two pieces and reassemble it once inside. I chose the later option. If you have the seam run vertically, (i.e. you build it as a left and right piece) you can create a "brest plate" at the top that effectivly hides the seam and also acts to add structuraly integrity. That is not what I did (see thumbnail below) so I ended up hiding my seam with exterior grade carpet.
Attachments
Heresy Alert!
Don't replace the bulkhead...
Since you can't get the whole piece into the boat anyway, consider this:
Find the point on the existing bulkhead laterally where the
damaged section begins inboard (toward the centerline).
Draw a vertical line from top to bottom just inboard of the point mentioned above.
Use a small skill saw to cut the damaged section on the line.
Use a multi tool to disengage the outer edge of the bulkhead.
Use the damaged section as a template for a new veneer plywood section.
Depending on the complexity of the outer edge attachment, this works.
I did it just this way.
Don't replace the bulkhead...
Since you can't get the whole piece into the boat anyway, consider this:
Find the point on the existing bulkhead laterally where the
damaged section begins inboard (toward the centerline).
Draw a vertical line from top to bottom just inboard of the point mentioned above.
Use a small skill saw to cut the damaged section on the line.
Use a multi tool to disengage the outer edge of the bulkhead.
Use the damaged section as a template for a new veneer plywood section.
Depending on the complexity of the outer edge attachment, this works.
I did it just this way.
Ggrizzard: I have actually been considering this as an option. The bulkhead is about 8” aft of the mast and compression step and post. So, the bulkhead is not integral to the mast. It is however support for the deck and the chainplates. It, too, was my thinking that replacing a smaller vertical section and tying it to the remaining bulkhead and glassed to the knee, which is glassed to the hull, would be sufficiently strong. Little piece of trim could cover the seam. Even purchased the smaller sheet of plywood. Then the folks at the Club started talking me toward the entire replacement. That is why I am seeking input from folks with experience with this particular boat, or similarly sized boats. Can one get the starboard bulkhead below in one piece? It was replaced once before by the previous owner, And there are no seams, so perhaps it can.
I can't address your last question as I've never been on that particular boat.
Perhaps others who have will chime in.
There are always purists who will opine for total replacement, but then again, they don't have the job staring them in the face.
When I finished my project in August, I had the cabinet maker who cut the plywood pieces come and inspect the install work...
He didn't notice the seam (no trim molding) until I showed it to him !
Perhaps others who have will chime in.
There are always purists who will opine for total replacement, but then again, they don't have the job staring them in the face.
When I finished my project in August, I had the cabinet maker who cut the plywood pieces come and inspect the install work...
He didn't notice the seam (no trim molding) until I showed it to him !
We will have several days of unseasonably warm weather the next several days. Thinking I might attack this bulkhead issue. Time off and warm weather, two good things. ggrizzard, interested in your or anyone else's opinion. Been taking heed to the idea of not replacing the entire bulkhead. Considering doing a lateral cut instead of a vertical. The condition of the lower half of the bulkhead is good. The glassed connections to the hull are solid. The benefit of doing a lateral cut and replacing the top half of the bulkhead is that any seams (if they don't turn out as nice as yours) would be covered by the cushions. Moreover, when it comes to staining it would minimize the need to as closely match the stain with the remaining piece. I foresee that being a potential problem, matching grain and color. Seems like replacing the top half would be adequately strong if the top and bottom halves are snugly fit with a good layer of Gorilla Glue in between (about 5 feet of connected surface). Maybe stronger for the chainplate connection way out on the outer edge since the entire top half would be a single piece? Since this boat has a compression post it seems like this approach would be adequate for deck support and chainplate stresses? New to boat construction and not an engineer, so feel free to tell me this is a terrible approach. Feelings would not be hurt. Thanks all.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,261
Consideration for the vertical as well as lateral strength-stress management on the boat as the hull and deck rotate/flex/twist during motion on the water.
The design of a bulkhead is to manage and control the limits of the forces experienced on the boat, to help the boat from coming apart. When you sever the boats bulkhead, then patch it back together, will the spliced together halves be able to still manage the stresses?
Consider the forces in play from all 3 directions.
The design of a bulkhead is to manage and control the limits of the forces experienced on the boat, to help the boat from coming apart. When you sever the boats bulkhead, then patch it back together, will the spliced together halves be able to still manage the stresses?
Consider the forces in play from all 3 directions.
A horizontal seam on a “mostly” compression structure that will experience shear forces isn’t great. I would anticipate it buckling and failing when challenged. By the time you splint the joint ( a but joint won’t cut it, even with floating tenons), I think you will be far ahead with a vertical joint. Matching wood grain and hiding seams needs to take the back seat to engineering ( backyard engineering).
I agree that a vertical seam is better, but there may be a compromise.
If your bottom section is rotted along with the area adjacent to the chain plates,
what about an "L" section?
As to the joint, regardless of which method you choose, I strongly urge you to review
the YouTube video series from a boat rebuilder from Denmark named "Mads".
His VLOG is entitled "Sail Life" and he replaced many bulkheads
and had to do them in sections as do you. He shaves the seams and fiber glasses them together. He's going to paint his, but you could add veneer after installation.
The group of vids showing his methodology goes back over the past two years
(not all grouped together), but the expertise he exhibits is worth the treasure hunt.
If your bottom section is rotted along with the area adjacent to the chain plates,
what about an "L" section?
As to the joint, regardless of which method you choose, I strongly urge you to review
the YouTube video series from a boat rebuilder from Denmark named "Mads".
His VLOG is entitled "Sail Life" and he replaced many bulkheads
and had to do them in sections as do you. He shaves the seams and fiber glasses them together. He's going to paint his, but you could add veneer after installation.
The group of vids showing his methodology goes back over the past two years
(not all grouped together), but the expertise he exhibits is worth the treasure hunt.