Tiny boat restoration

Hello everyone,

I'm restoring and modifying an 8ft Jon boat. I would like some input from people that have completed some of the things I have left to finish. At some point a previous owner removed the middle bench and it's causing quite a bit of flex. I would like to leave the bench out and put a wood/carpeted floor on top of a very low aluminum frame. Has anyone fabricated an aluminum brace/support for the floors and sides to prevent flexing? I'm capable of welding and bucking rivets. I would prefer to buck the rivets for anything below the waterline instead of welding or using pop rivets. I have removed the front and rear benches so I could braze some cracks and put new foam. What would be the best choice for foam to completely fill the bench cavity? Also what would be the best wood to use for a new transom? Most likely I will only be using a trolling motor. I appreciate any help, thank you.

To be honest, you would be money & time ahead just to find a unmoletested boat. But if you want to proceed, one way to add flotation & rigidity at same time would be to line floor & sides with foam board, retained by aluminium angle. Exterior plywood for transom, waterproofed with old timers formula.

I got the boat for free when I purchased another one. I have plenty of flat stock, angle and rivets left from different types of projects. About the only thing I don’t have on hand is the foam, marine plywood, carpet and wood for the transom. I use to build aluminum floors on refrigerated trailers, so I have a round about idea for the floor framing. I’m wondering if 1/4X1 flat stock buck riveted to the walls and floor then welded at the joints will stop the flexing or do I need to also add round stock going from the wall to floor. Thank you for the tip on the foam, I want to lay some in between my framing before I put the plywood down.