Bulkhead issue, repair or replace?

Thread starter #1
Hello,

I am new to the forum. I recently purchased a 1978 J24, hull 973. It was a very good deal but it does have a soft spot in the bulk head that I would like to address before putting the mast up and putting it in the water. It is soft on the port side between the chain plate and the hull. It does not seem to be soft where the chain plate is. The spot is about 10 inches in diameter. I can try and get some pictures but you cant tell its soft without actually touching it. My question is, do i need to cut out the whole bulkhead or could i get away with just patching and epoxying the spot. I am the second owner of this boat and it has never been raced. All of the deck hardware is in its original location and there is only 1 soft spot where someone did ad a manual baler pump at some point. I don't plan to race this boat as there is a good size fleet already where I am and plenty of crewing opportunities. I plan to use it to practice what I've learned while racing.

Thank you!
 
#2
I have a similar problem on the starboard side. I want to cut out and replace the entire bulkhead. Does anyone know what material to use? I'm guessing 1/2" marine grade plywood.

Any help would be appreciated.
 
#4
Any advice? My plan is to carefully cut out the old bulkhead with a Dremel tool and use it as a pattern for cutting the new one out of 1/2" marine plywood. Once I sand down the area where the old one came out, I was going to use epoxy to place the new one in.

I sure do appreciate you posting this and answering my post!
 
Thread starter #5
That is pretty much exactly what I did. I only ended up doing the port side and tied it in to the middle. I did three layers of fiberglass but I was told I could have gotten away with two. I have been racing it for two years now and it appears to be holding up well.
 
#6
That is pretty much exactly what I did. I only ended up doing the port side and tied it in to the middle. I did three layers of fiberglass but I was told I could have gotten away with two. I have been racing it for two years now and it appears to be holding up well.
I’m having a hard time finding 1/2 inch marine grade plywood. Where did you find yours?
 
#8
A few things....

1. I have done this twice on my boat. Even marine plywood will start to rot and delaminate if there is water in there for a month, or over the winter... MUST keep it dry!
2. I may have used marine plywood first time, but not the second. Maybe I shouldn't say this, but I don't think any measurer will reject your boat if they suspect or think that they know that it's not marine ply. [That's what's specified in the rules] You can give it a couple of coats of epoxy to make it water resistant.
3. It's a big and messy job to get it out. I don't think you'll get it out of there with a dremel tool. I don't remember (first one: 1996), but if it's original maybe it's not so hard to remove from the fiberglass bulkhead facing on the 'main saloon' side. Certainly the second time I did it, it was difficult to remove since it had been epoxied to that fiberglass surface. In that case, I used a router and cut many slots as a way of destroying most of the plywood, and then chiseled or ground away the remaining plywood between the slots.
I suggest a grinder with a cutting disc to cut the tape attaching it to the hull and deck. You'll make good use of it (along with some 36 grit sanding discs for preparing the surfaces you'll bond to) in this project.
4. You can't get the replacement bulkhead in there in one piece, and maybe not even in two. It's very difficult to get it between the mast beam, fiberglass bulkhead, and hull stiffeners in the forepeak (ie. owner's stateroom) that support the vee-berth.
5. I don't think you'll have any luck preserving the original to make a template, but it's easy to make one from cardboard. Cut a bunch of largish pieces with some mild curves and you can lay them over one another and tape them together to get the shape. If necessary you can easily fair the curve between pieces. Make a final template on a new, big piece of cardboard. I suggest doing the template-making before removing the old bulkhead.
6. When you put it together, use epoxy thickened with a high-density (strong) thickener to fill gaps at the hull, overhead, and where it joins to the other half (or whatever) of the bulkhead. At the hull and deck, make a cove-shaped fillet. [Empty caulking tubes are useful for applying thickened epoxy in significant amounts and in corners] Then overlay that with at least 2 layers, maybe 3, of 10 or 12 ounce cloth, properly wet-out. If you don't fill the gaps so it fits tightly against everything, it will 'work' over time as the boat goes through waves and could ultimately break the the glass tabbing. The bulkhead is an important structural part of the boat.
-- I would not take great effort to epoxy the new bulkhead to the fiberglass bulkhead. In retrospect, it's not necessary. I would suggest maybe running 3 ribbons of thickened epoxy across it where it is in contact with the fiberglass bulkhead. Probably put the epoxy on the fiberglass before pushing the bulkhead in place. You want to hold it together, but the fiberglass part isn't structural.
7. *** Ding ding ding! Important! On a boat of your vintage, if it hasn't been done, you should caulk the hull/deck joint with polyurethane BEFORE you replace the bulkhead. My 1978 boat once got 75 gallons of water below just sitting in a boatyard over a couple months in the winter. And we were always bailing on windy racing days. The boats were initially caulked with bedding compound which isn't resilient or adhesive. Rip off the toerails, take out the hull/deck fasteners, pry up the deck, and scrape that stuff out. Then re-caulk with polyurethane. There's no point in putting in a new bulkhead if the boat isn't dry. That's why I re-did my bulkhead 8 years after I first did it. The second time was in 2004, and it's still fine.
7 a. You can use Loctite PL polyurethane from Home Depot for ~$5.65 per tube. Much cheaper than the 3M stuff from the marine store. And I don't recommend using 3M 5200 for anything. It's stronger than the chopped strand mat laminate that the boat is made of, so if you ever have to remove something, it destroys the laminate. 4200 or the Loctite are fine. They're adhesive and waterproof but you can still get them apart, with some effort.
8. If you have any rot in the deck in the area of the forward part of the hatch tracks, you might find that you have access to do the repair there while you've got the bulkhead out.

I'll make another post with some pictures. I was going to insert some here, but I just can't make sense of the SW interface when I experiment with posting them. Not sure how they will come out.
- Vince Harris
 

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#9
Surprised to see that photo there! I think there's a lot of capability here, but tough to tell how it works.
That's about to start cutting slots in the bulkhead to destroy it and enable its removal.
 
Thread starter #10
I used an oscillating multi tool to cut the old one out, mine was made by Ridgid but I assumed when you said Dremel that is what you meant. I only did the port side since the starboard side was still solid. and I only did from the door opening to the hull. the space above and below the door were also still solid. My thinking being that my new work would not be as solid as the original so if its not broken then I won't fix it. I did three layers of fiberglass as well but was also told that two would have been fine. Make sure you research how to "tab" in new pieces with fiberglass and how to overlap the layers for strength. I may have gotten lucky but i was about to use the fiberglass i cut out as a template for the new piece. I just cut it a little too big and sanded and trimmed as needed for it to fit. As for attaching it to the fiberglass side facing the cabin side i believe i used adhesive caulk. and a couple small screws to hold while that dried. once that dried the new piece of wood stayed in place for me to be able to do the fiberglass work. In the next season or two i plan to tackle the vermiculite job.
 
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