Replacing Bulkheads in Fiberglass pontoons

Hey Guys,
I have a very low speed application on my old 34ft houseboat. This thing is a 1986 Aqua Cruiser. About 5 years ago the bulkheads started breaking loose. The top of the pontoons are glassed over but was thin and porous. Enough water got in to rot the glassed in bulkheads. The fiberglass in the logs seems fine but without the bulkheads its week and now we have a major project on our hands.
We are thinking of glassing in aluminum bulkheads since we have fabricating equipment available. Maybe 1/8" aluminum with a 1" flange welded on the edges.
My main question is about the resin / mat. We are not concerned with anything but a nice bond that will last. Thinking Epoxy resin (ran across some Laminating Epoxy from "Pro marine" for about $60 a gallon on ebay. Should we use Bi axial mat ? How many layers of Mat?
Any thoughts are welcome.
Thanks!

Attachment 391894

If you use alum, make the blkhds a little small and use some foam pcs to space the metal off of the hulls. 1/4'' X 1'' strips of core foam would work. (1'' flanges) Really, I would suggest you use some decent 1/2''or 3/4'' ply and glass it in. Much cheaper and easier to work with. Also, the original material and you could use a cheaper poly resin. One or two 6''-10'' wide strips of 1700 or 1708 bi-ply on each side would do it. Epoxy for alum, epoxy,poly or vinyl for wood. jm2ts

Upside down!
A layup worse than hydrostreamhttps://youtu.be/83Sf6cNGTFM

Looks like a real mess. Glad i'm not doing that kinda work anymore....Any more thoughts on the rebuild method?

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Originally Posted by XstreamVking

Looks like a real mess. Glad i'm not doing that kinda work anymore....Any more thoughts on the rebuild method?

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Man that is ugly isn't it! I'd like to clean it out with a "Hotsie". I have been speaking with a guy from California to determine the best products for the bonding.
Fiberglass cloth and which resin to use.
The dude is like a bonding gear Head. He had me confused so I sent him pictures of exactly what we are trying to do.
SpaceX and others use there epoxies so he was used to speaking with folks a bit smarter than I so we resorted to photos and sketches.
We have a long way to go.
It looks like the forward most bulkhead is still intact. They started popping lose about six years ago. Then just rotted away. The hull went from angled on the sides to a natural radius shape.
I was getting ready to dock it for winter (from bouy) and saw about a one foot long crack in the side. I'm not sure if my insurance would have paid for the $450000 house boat next to mine. So it was time to pull it.
I will let you know what we end up doing.

Is there really a resin that will bond aluminum to fiberglass? Anything I have seen in my experience where an aluminum flange is glassed it fails. Have boat manufactures still trying to do it on flanges to bolt fiberglass consoles to a deck and we end up running bolts through the console and then through the flange.

I'd use a quality epoxy like Raka or MarinEpoxy (West if you want to spend more) and marine plywood. Completely saturate it, and tape to the bottom and sides with biax. Will last longer than the rest of the boat.

The rebuild with epoxy & plywood will be a lot easier than the de-rigging / stripping / re-rigging part of the job.

I have had experience with those boats before. If it were mine I would go the route that Matt said and glass in good plywood bulkheads. Also, give the entire wood bulkhead a couple coats of the epoxy to seal it. Like he said it would last as long as you will use the boat. However, I would not 'close off' each section between the bulkheads. Leave a cut out at the bottom of each one so if any water were to intrude again it can drain to the back. Install access plates so that you can add auto bilge pumps inside the rear of each pontoon. These boats were notorious for water intrusion into the sections. The flange at the top of the pontoon was almost always the culprit. It would separate around the edge and let water in while underway.