Mainship 40 DC - Rear Salon bulkhead

Looking for any info on the construction of the exterior bulkhead wall between the sundeck and salon. The wall with the rear-facing salon window.
It seems to have been built with formica?
Also, the small angled wing-walls on each side, were poorly sealed, causing core damage around them.
Is this common?

Did anyone find an answer on this? My bulkhead is rotten and I would love to have a Router file or DXF. DWG to be able to cut on CNC and replace.

Hi JCREASY,
I have had no replies. I think we are on our own with this one.
I think if you get seriously looking at it, you will find water damage in more than the bulkhead - check out the little wing walls at the rear outboard sides, and the forward edge of the sundeck as well. Mine is a bit of a mess. Still usable currently, but a long-term concern.

We have removed the rear salon bulkhead and the little angled wing-walls as they were all water damaged. See pic.
I have had a new rear bulkhead made of cored fiberglass and will be installing it shortly.

In progress

This is our newly built cored fiberglass rear bulkhead with the original window cleaned up and re-installed.

In progress

I have also cut off the angled wing-wall extensions that were always a trip hazard. They were cored with plywood-formica and rotten. See blue lines in this pic.
I have also ground off a small molded-in detail that was always a knee-knocker going up or down to the side decks. See red circle.

Spitfire said:

Hi JCREASY,
I have had no replies. I think we are on our own with this one.

Click to expand...

Honestly, I think the original post was lacking a model year of the vessel and a clear scope of the problem. For example.......

Exterior Bulkhead wall: Is this port, Stbd, aft? A bulkhead either separates two interior spaces, or in some cases, an interior and exterior space. What spaces are we talking about here?

It's not clear what you're calling the 'Sun Deck". The cockpit? The Flybridge? Flybridge, aft?

For water damaged cores, there is really only one solution.

1) Cut out the fiberglass skin (preferable on the inside or less obvious side).

2) hog out the rotted coring material (balsa)

3) Replace the coring material and epoxy and glass in place.

4) re-glass fiberglass skin

5) paint/finish repair.

in progress

Sorry for the lack of detail. It is a 1988 40' Mainship "Double Cabin".
I have included a pic (not my boat) to describe the areas of concern.
SD = Sundeck.
BH = Bulkhead (the wall between salon interior and sundeck exterior. It was constructed of plywood with wallpaper on the inside and formica on the outside. The plywood was rotten at the bottom.)
WW = small angled wing-walls either side of the Bulkhead. They are fiberglass on the outer facing surfaces, and were finished with plywood and formica on the inward facing (still exterior) surfaces.

No core to remove. Just had to make new cored panels completely.

in progress

We installed the new bulkhead. Adhered with 5200 along the horizontal top and bottom, and glassed in on both vertical ends.

Looks very nice. Also looks like a lot of work, keep it going.

Why 5200?

Spitfire said:

We installed the new bulkhead. Adhered with 5200 along the horizontal top and bottom, and glassed in on both vertical ends.

Click to expand...

Just curious - why 5200 top and bottom rather than tabbing in w glass/resin?

We used the adhesive/sealer top and bottom because of the joint design there. The previous plywood/formica bulkhead was originally installed with screws. I just did a good prep on the surfaces and then glued them together with the 5200. To tab them, would have meant much more work to hide the fiberglass afterwards.
Both far ends are going to be covered anyways, so no issue there.
Good question.