Bulkhead replacement fitting problems

[Ritdog]

I'm in the process of refurbing an Oday 25- I pulled the bulkheads out because they were getting old and had water damage. I'm replacing the half inch with three quarter ply. BUT, am finding that I have to make them 5/8ths - 3/4" smaller between the cabin top and the settees, and/or the cabin floor. Don't know why.

Am assuming that maybe the cabin flattens out without the bulkheads in there to hold the top up?

I did this once before with no problem, on another 25. I had to KICK those in for tension, but these new ones are just not going to go.

Anybody see this before?

 

[cb32863]

Maybe because at the top of the bulkheads the extra thickness is not letting it fit up in the groove? I used a router on mine and beveled the top like the originals were. They were 1/2" and you are replacing with 3/4". I did the same but routed out for the chain plates and as I said, beveled at the top. Makes sense to me that having an extra 1/4" of thickness is going to make a difference in how things slip in to the groove. May want to be sure your chainplates are going to align correctly with the slot in the deck too.

 

[Technodad]

After I took mine out they were a little tight to go in too. I ended up kicking them in.
I've since realized that they and the mast post hold the roof up so I think you need only to get your car jack and a piece of 2x4 cut to fit between the jack on the floor and the roof, jack it up and put the bulkheads in, I reckon everything will fall into place just nicely!!!!!!!!!!

I have also learned that the sliding hatch cover flattens out over time, this leads to the hatch rubbing in the middle on the underside onto the roof rib....anyone noticed this? My solution was to put 1/4" strips of oak under the wood hatch slides, now it is fine. When I made my new boards I made them 1/4" higher to compensate.
My theory is that the gel coat shrinks more than the fiberglass underneath and curls the panels flattening them. My bilge cover is warped to hell, curled up because it was flat to begin with, it stands to reason that the roof will flatten down as well, that's why it drops when you take out the bulkheads and post.
Check out the gelcoat cracks on your topsides, they don't go all the way through, just the gelcoat, this shows the gel shrinks more over time.

Just my thoughts...........

 

[Indysailor]

My sliding hatch scrapes as well, but I've never really thought it was a big enough of a problem to worry about. I'd never really put the cause together though.

As for the bulkheads not fitting, I guess my question is why change the thickness? I replaced mine with the same 1/2" and the job went very smoothly. Jack up the roof, remove, cut new ones and install- probably 5 hours of work, total. It's a little more work on a 25 because they are tabbed in place, whereas on my boat the originals were not tabbed in.
Are you beefing up the load carrying capacity of your rig, just looking for extra piece of mind? Not a criticism, but rather I'm curious about the reasoning.

 

[Ritdog]

Thanks for the input guys- I WAS thinking of jacking the headliner up, but with my luck it would just punch through, or crack, so was leery of doing so- I might try that for the last piece though, just to see what happens..... The headliner on a 25 is usually solid to the deck over it , so I'm not sure how well that will work though....

I went with 3/4" in my first 25, just because it would be a bit stronger than the 1/2" . I did taper the edges to fit in the slots at the top, and the chainplates fit very nicely. It all just seemed more solid after I did that. This boat had some standing water for a while, so the bottoms were parting a bit, (the compression post was just rotten at the bottom...)

In good news, I found marine vinyl at half price, so am able to do the whole hull liner for about $160, front to back! I'm going to do the bulkheads with a slightly thicker slightly off-white vinyl that feels like leather.

We are cold here now in Maine, so I am switching to wiring and all the other stuff that I don't need heat for. Ifx we get sosme warmer days, I'm going to break out the heat lamp and do some poly work!

Actually, I'm thinking of doing a whole "page" on this rehab - will try to get it together.

 

[Indysailor]

I only had to jack the cabin top up about 3/8 inch to slide my bulkheads out. Good luck with the work; I look forward to following the progress!

 

[25yearslater]

Same as Indy I only jacked 1/2 to 3/4 inch. My hatch was scraping so I made new sliders from the teak I bought. They wear something fierce over time which might be why these older boats experience this. While your at it check your support under the compression post for degradation. I just replaced mine and should have checked during the restoration.

 

[Golden Road]

On my 23 I found that the clearances expanded a lot on a hot day. note for future.