O'Day 25 Bulkhead Replacement

Ritdog

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Jul 18, 2011
184
Oday 25 Portland, ME
Dan is right- one per bulkhead, 6 total including the galley and galley wall.
 

Ritdog

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Jul 18, 2011
184
Oday 25 Portland, ME
I had about 3 feet of blocking, then carefully placed a vertical 4x4 on the jack with a plywood panel on top for the ceiling. the ceiling . Not that hard to do- you are just jacking an inch or so- don't want to crack it! Better to put the compression post in last also.....
 
Sep 24, 2018
2,549
O'Day 25 Chicago
I got the bulkhead out last night. Wow those cabinet screws are a pain! They look like #10-12 stainless screws that dont like coming out or like to strip. I used an impact style screw guns. This is one thing I wish I had spent more money on. It has loads of power and instead of reducing power when a screw is stuck the impact feature starts hammering away which strips the screw head. This one is a black and decker 20v. I used a Craftsman one a few years ago that got just about any screw out even if they were severely stripped.

I used a sawzall with a bimetal (medium toothed) blade and it worked very well. Plenty of control and it only took 5 minutes to cut through the glass. I would recommend this to anyone else removing bulkheads.

Anyways, I found about a 1/2" gap between the bulkhead and the hull. They did a poor job cutting the bulkhead at the factory so I assume the gap was a lazy worker ensuring that it would fit. It's held up for 40 years so I'll probably do the same. The deck was stronger than expected without the bulkhead. No visible bending and it barely creaked when I walked on that area. I initially brought wood to support the deck while the bulkhead was out but after seeing how strong it was I skipped this step.

I have a few questions at the moment.
-Can anyone recommend a varnish to make the new plywood look somewhat close to the old or is this a case by case scenario?
-When I reinstall the bulkhead how many layers of glass should I apply and what type?
-If memory serves me correctly, someone mentioned that the bulkheads are almost identical. Can anyone confirm this?
 
Last edited:
Jun 2, 2004
1,923
Oday Day Sailer Wareham, MA
The reason for the gap is not just to avoid trimming exactly at the factory, the gap is there to prevent a "hard spot" where the hull touches the bulkhead. Fiberglass flexes and if the bulkhead fit tight it would ultimately result in a potential crack in the hull surface where the bulkhead presses against the inside of the hull. Some high-end builders will actually insert a foam strip between the edges of the bulkheads and the inside of the hull to cushion the area and if wedge shaped, tapering away from the bulkhead on both sides, will allow an easier application of the glass tape used to secure the bulkhead in place.

I would still use a wood or other material support to hold the deck up while the bulkhead is out, it may seem strong enough, and is, but the deck may still begin the sag down a bit without the bulkhead's support and you may actually want to slightly lift the deck up before installing the new bulkhead to make it easier to slip it into place. Several owners have left out the temporary supports while replacing bulkheads, only to have trouble with the new bulkheads not fitting because the deck has sagged and/or the hull spread slightly without the bulkhead in place.
 
Sep 24, 2018
2,549
O'Day 25 Chicago
I can dig up a piece of foam to maintain that space while the resin sets. I was pretty surprised at how much space was between the deck/hull and the bulkhead. So much so that I didn't bother with the temporary support. If I have time I'll cut out a board to help maintain hull shape.

Would this marine plywood from Menards work or does it need to be higher quality?

https://www.menards.com/main/buildi...ab-marine-plywood/1251595/p-1444452502117.htm
 
Jun 29, 2010
1,287
Beneteau First 235 Lake Minnetonka, MN
I can dig up a piece of foam to maintain that space while the resin sets. I was pretty surprised at how much space was between the deck/hull and the bulkhead. So much so that I didn't bother with the temporary support. If I have time I'll cut out a board to help maintain hull shape.

Would this marine plywood from Menards work or does it need to be higher quality?

https://www.menards.com/main/buildi...ab-marine-plywood/1251595/p-1444452502117.htm
That is the same stuff I bought. make sure it is half inch otherwise you will be doing a lot of mods and routing.
 
Sep 24, 2018
2,549
O'Day 25 Chicago
I just looked at the spec sheet for the Menards plywood. It's 5 ply douglas fir. Not exactly marine grade I'm told. Can anyone recommend a source for some real marine grade plywood near Chicago?
 
Sep 24, 2018
2,549
O'Day 25 Chicago
I ended up getting plywood from Owl Lumber. Cost was about $80

I cut and applied stain to one side of the wood last night. I'm hoping the stain will lighten up as the wood soaks it in. I will find out tonight.
2019-03-05 19.47.51.jpg

I suspected that you can get two bulkheads out of a single sheet of plywood. It turns out you can. Here's the proof2019-03-05 19.08.29.jpg