Rebuild backseat on 96 prostar 190

I just wanted to know if anyone had any ideas on how to fix my back seat. It is really starting to sag in the middle. Right now I have 4x4 underneath it to support it, but was looking for suggestions on how to rebuil it or reinforce it.

Your best best would be to get some new marine grade plywood. Use the old boards as templates for saw cutting. After you've cut them to size, coat them in fiberglass resin, you can also add some glass plies for added reinforcement if you need added strength.

Good Luck - Chris

I was thinking about using starboard? anybody have any thoughts on this idea? just cut it and your ready to go? no fiberglass

I was thinking about using starboard? anybody have any thoughts on this idea? just cut it and your ready to go? no fiberglass

Adam, I don't know what starboard is but you could use 1/2" MDF and coat it in fiberglass epoxy. They factory used a plastic board for the base on the seat. You can always order a plastic sheet and cut it to the correct size. Check www.mcmaster.com they have a bunch of different kinds, you should be able to find one that is sturdy and not too expensive. This would keep your boat wood free, the same way it came from the factory.

It was made out of aluminium honeycomb you should be able to get a replacement at your local dealer

I would take it out and leave it,more room.If someone complains let them set on life vest.

aluminum honeycomb is VERY expensive stuff, check McMaster for prices. Starboard is supposed to be pretty good stuff, but is not as stiff as the honeycomb and would need more bracing. http://www.kingstarboard.com/Products/StarboardFamily.aspx

I dont know what the back seat looks like in a MC but I was thinking about putting a plastic tank as a seat bottom for the back seat in my 86 nauti. Then you could have the ballast and seating all in one.

I just want the seat to be sturdy again so I can lay it up top to extend the "sundeck" Once i get it up there people can sit on it and i can have my 600lb fatsac underneath.

I think the cheapest and easiest way is get some goog 3/4" plywood, waterproof it and put the foam and skin back on. The other thing you could do, if you can straighten it out is get a couple pieces of AL angle iron (2x2 or smaller), take the cover off and thru bolt them from side to side under the seat w/ carraige bolts.
Thats what I'm going to do if mine gets any droopier.

never heard of AL angle?? where can you get it? Some mentioned to me to get two pieces of 1/2 inch plywood put a small layer of fiberglass in the middle then fiberglas expoxy the whole thing to waterproff. overkill? thrall what do you recomend for waterprofing? how much weight will the plywood hold?

Two layers of half inch ply should work well also don't think you need to fiberglass it, that won't add any strength unless you use alot of layers, just glue them together and use alot of screws. With 3/4 ply, use good BB plywood (7 layer). I'd still put a gusset underneath the seat. 3/4 or 1 inch of plywood won't hold up very long with adults stepping on the midle of the seat getting in and out of the boat.
By AL, I meant aluminum angle (no rust)to keep the center of the seat from flexing. Run 1 or 2 pieces from side to side on the front half of the seat, right where you would get the most flex. If you're going to use it mostly as a sundeck, you could get by without the brace underneath, as people will not be stepping on it.
Unless you have problem w/ stuff staying wet, I'd just use a couple good coats of Thompson's Water sealer, or a good deck stain/sealer to water proof it.
Good luck