Dinghy Floor

[mxtommy]

Hi,

Recently the Air floor in my inflatable 9ft dinghy has been giving me grief. I thinking of replacing it with some 3/4 in marine plywood. Has anyone ever done this before? Does it add way too much weight? Is it thick enough? One of the reasons I wanted to put plywood in is (aside from the fact that it's constantly leaking) that currently I find there's a lot of flex in the dingy when planning with the motor. I'm hopping it'll be better with firm support.

Also, would maybe some 1/2 in plywood with some thin re-enforcing planks be better (lighter?)

Thanks!

[JimsCAL]

I made some 3/4 inch marine plywood floors for an inexpensive Sevylor I had a number of years ago. No problems, worked well, and still in good shape when i retired it and bought an Achilles.

[sailingdog]

3/4" marine plywood is pretty heavy. It might be a better idea to make up a new floor of foam or balsa-cored fiberglass.

[heinzir]

I replaced the flexible fold-up floor on my 9' Achilles with a solid piece of 1/2" exterior grade plywood. I put a faired reinforcing 1 X 2 on the bottom side and thoroughly sealed and painted the whole assembly. Still going strong after 17 years.
The dinghy is never deflated except for a yearly cleaning; it is stored inflated. I added some wood cleats to the floor to keep the fuel tank in place and mounted a small tool box under the seat.

[Minnewaska]

If the dink wasn't designed to have a rigid floor, I suspect you would have to consider reinforcement or chafe protection.

[mxtommy]

Heinzir, What did you use to reinforce exactly?

Minnewaska, When I bought the dinghy, there was an option for an aluminum floor instead of the air floor. (which I stupidly turned down...) I called the manufacture but they said that it would be like $400 or so for a new aluminum one.

Sailingdog, I though about that. My worry it that to make the fiberglass thick enough wouldn't it not save much weight?

Thanks everyone!

[DwayneSpeer]

If you do replace it with plywood make sure it's marine grade not just exterior grade. There is a difference. The exterior grade just will not hold up to lots of water. Also be careful as some lumber yards will try to tell you there is no difference other than cost.

I know this from experience as a hatch cover I rebuilt last Summer fell apart this Spring. I got to rebuild it; doing it right this time.

[sailingdog]

If you make it a cored laminate, as I suggested, it won't be anywhere near as heavy as 3/4" marine plywood.

Originally Posted by mxtommy

Sailingdog, I though about that. My worry it that to make the fiberglass thick enough wouldn't it not save much weight?

Thanks everyone!

[heinzir]

Originally Posted by mxtommy

Heinzir, What did you use to reinforce exactly?

I put just one reinforcing rib down the center of the plywood on the bottom side. I ripped a 1X2 down to 1X1-1/2" and rounded the bottom side that comes in contact with the floor. My dinghy does not have a "keel" chamber, just the flat rubber floor. I put the reinforcing rib on the bottom of the wood floor instead of on the top with the intent of giving the bottom a little bit of a "V" shape to help keep her going straight. Maybe that is why the exterior plywood has held up so well after all these years: water can collect in the V instead of soaking right into the wood. I didn't put any reinforcement on the edges of the ply; it needs to squeeze into the crevice between the tubes and the floor. Of course the plywood and especially the edges were well sanded, sealed, and coated with several coats of paint.

[petes334]

Those are some great tips. Thanks.