Hi List. I've looked around but can't seem to find what I'm after. Our 1979 Catalina 30 is in need of a replacement bulkhead. The starboard main one that the upper stay is bolted to. It has had water damage and is moving slightly where the chainplate is bolted to. In looking it over I can't seem to see what exactly supports this bulkhead besides the cupboard on the left and the seat on the right. Surely there is something else that holds all of this as the chainplate is fastened to this bulkhead. I looked around the list but didn't really see any pics on someone replacing this one. Or did I miss it somewhere.
Bulkhead replacement
- Thread starter dnimigon
- Start date
I see posts all the time about replacing the entire forward main bulkhead because of past chain plate leaks. If your bulk head is not completely rotted, then why not have larger, heavier duty backing plates made for the chain plates which offset the original mounting holes? If there is still good wood in the core of the ply wood then this might avoid a costly & time consuming repair job. A larger backing plate would increase the size of the mounting area so that there is a larger area bearing the stress of the chain plate, & would increase its strength. But if the core is completley rotted away, then this idea may not work. My 2 cents.
The opffset would screw up the pull from the shrouds and mast above, that's why.
Chainplate rebedding should be part of regular MAINTENANCEa, but sadly is not.
Some Catalinas, like the C30 and C36 have this "feature."
Our C34 does not.
The C36 Association website has a very good writeup of bulkhead replacement by John Reinman who sometimes shows up here (JohnR).
Luck for us ours bulkheads are still in great shape. However the last few owners of out boat opted for the smear silicone over the top method of bedding. After scraping off the junk I rebed with butyl, took about 5 minutes to clean and 2 minutes to rebed the top plate.
On our boat we have a turnbuckle from the bottom bolt on said chainplate down to the liner below the bench. Wish I had a picture but am not at the boat. Do not ever know why it's there and only on the starboard side.
On our boat we have a turnbuckle from the bottom bolt on said chainplate down to the liner below the bench. Wish I had a picture but am not at the boat. Do not ever know why it's there and only on the starboard side.
D,
If I had your problem here's how I would apply a fix. It's a bit of work without removing the bulkhead yet, keep a decent look. I would use a boat carpenter to do this. He may even have a better fix than mine.
Hopefully, you would cut out a larger square or rectangular area into good wood. Make a replacement piece to match size & bulkhead thickness. I would epoxy this in. This is the tricky part as you want to keep the plane flush with the orig. bulkhead. Then you would make wood framing say 2-3" wide for both sides, like what a picture frame would look like. Frame should be "U" shaped for the bottom & the two vertical sides only. I would make this as a one piece frame for both sides.
Keep in mind, that you want to do a nice job so your finish look will be nice. Frames made, I would epoxy these (both sides) to the new replacement wood cutout. A 2" wide frame would be centered over the cut edges (1" overlap). I would countersink screws from both sides (long enough as not to pierce thru the opposite side frame of the bulkhead, using plugs you can buy for the finished look. Then simply stain, oil or varnish to finish it.
A good boat carpenter will make a nicer looking repair than you can without it looking bad. He may have even replaced bulkheads before & has a whole one piece bulkhead fix for this. Good luck......
CR
If I had your problem here's how I would apply a fix. It's a bit of work without removing the bulkhead yet, keep a decent look. I would use a boat carpenter to do this. He may even have a better fix than mine.
Hopefully, you would cut out a larger square or rectangular area into good wood. Make a replacement piece to match size & bulkhead thickness. I would epoxy this in. This is the tricky part as you want to keep the plane flush with the orig. bulkhead. Then you would make wood framing say 2-3" wide for both sides, like what a picture frame would look like. Frame should be "U" shaped for the bottom & the two vertical sides only. I would make this as a one piece frame for both sides.
Keep in mind, that you want to do a nice job so your finish look will be nice. Frames made, I would epoxy these (both sides) to the new replacement wood cutout. A 2" wide frame would be centered over the cut edges (1" overlap). I would countersink screws from both sides (long enough as not to pierce thru the opposite side frame of the bulkhead, using plugs you can buy for the finished look. Then simply stain, oil or varnish to finish it.
A good boat carpenter will make a nicer looking repair than you can without it looking bad. He may have even replaced bulkheads before & has a whole one piece bulkhead fix for this. Good luck......
CR
D,
I forgot to mention that the upper shroud should be slackened or removed before attempting this fix. But, before you do this, remove the "Leaking" chainplate and properly rebedding it. I use Dow Corning 795 for top deck fittings however, Mainsail & Stu says butyl tape is the way to go. I will try butyl on my future caulkings, but I digress somewhat on this. These guys know their Sh**t, follow their lead, it tried & Proved. you can use the position of the newly caulked-in chainplate to use as a template for mounting & drilling the thru bolts after the your modifications.
This will become your template for mounting the chainplate & drilling mounting holes to secure it in place to your newly modified bulkhead. Again, use this as a template to locate & drill your new holes for the chainplate attachment, keep tight tolerances in drilling.
The IMPORTANT thing to keep in mind is, to be as exact as you can in cutting & making the cutout replacement piece, the truer, the better. Your chainplate should be disconnected from the shroud or your spar should be stepped. Re-bed this chainplate first. There are threads dealing with recaulking of chain plates on SBO, I suggest you check them out & you read these first before starting. Then, it all comes down to your comfort level as a do-it-yourselfer, or use a ship's carpenter. Don't you just love a job well done man? It could end up as onward & upward experience. Keep us posted.
CR
I forgot to mention that the upper shroud should be slackened or removed before attempting this fix. But, before you do this, remove the "Leaking" chainplate and properly rebedding it. I use Dow Corning 795 for top deck fittings however, Mainsail & Stu says butyl tape is the way to go. I will try butyl on my future caulkings, but I digress somewhat on this. These guys know their Sh**t, follow their lead, it tried & Proved. you can use the position of the newly caulked-in chainplate to use as a template for mounting & drilling the thru bolts after the your modifications.
This will become your template for mounting the chainplate & drilling mounting holes to secure it in place to your newly modified bulkhead. Again, use this as a template to locate & drill your new holes for the chainplate attachment, keep tight tolerances in drilling.
The IMPORTANT thing to keep in mind is, to be as exact as you can in cutting & making the cutout replacement piece, the truer, the better. Your chainplate should be disconnected from the shroud or your spar should be stepped. Re-bed this chainplate first. There are threads dealing with recaulking of chain plates on SBO, I suggest you check them out & you read these first before starting. Then, it all comes down to your comfort level as a do-it-yourselfer, or use a ship's carpenter. Don't you just love a job well done man? It could end up as onward & upward experience. Keep us posted.
CR
I had the same exact problem. It's an easy fix, more or or less. I really don't have the motivation to type an entire post as to the fix, but if you are interested, call me at (425) 765- 1359 this weekend. I will talk you through the whole problem. SS
Stu, I'm not advocating changing the angle at which the chain plate is mounted through the deck, only installing a much larger stainless steel mounting plate which would mount to a larger surface area of the bulkhead, where there is still good wood left to mount to. The existing chin plate attachment could then mount to the inner plate & thru bolted to sandwich the chain plate attachment together, & thus increase the surface area of the chain plate attachment & increase it load bearing ability. This would at least prevent it from ripping out through the deck if the bulkhead attachment is rotted.
But as I stated before, if the bulk head is completely rotted away, then this won't work, but it would work of the rot is only around the existing mounting holes. I like to find ways of repairing what is existing rather then tear out the bulkhead completely, which is a hell of a job.
Read all your ideas. I have no problem replacing the bulkhead. Work with wood all the time so don't see an issue doing this. I was more concerned with how the chainplate is supported. Is all the upper stress/pull taken up by the deck area and the bulkhead is just a cosmetic item. I assume Catalina has some sort of inner structure in the deck area to take the pull of the stay. There is some upper movement in the plate when under load.
If you go to the Catalina factory website, and look up the chain plate replacement kit, you'll find that now it is U bolts. They are mounted with an aluminum 90 degree "angle iron" plate. Another plate anchors the bulkhead to the bottom of the fiberglass shelf. This continues in the Stb side. This is for the lowers. The uppers chainplates have been reinforced with an angle gusset and also angle plates to the bulkhead, to the sitting area. There is a picture of the kit. I have the equivalent that I made on my own. All is tight and loads are not much better distributed.