Diamond Plate floor

So I am going to put a diamond plate floor in my boat. My question is, do I need to put flotation under it first? I am worried that water will get down in there, and the flotation will not let it drain to the back? I was just going to put it right on top of the metal stringers, so there's not much room anyways. Or should I put channel down first and then the diamond plate on that? Any feedback is really appreciated! Its my first build. Trying to make a sweet catfish boat...

You definitely want to put foam board in there. Not only will it provide a little bit of flotation, it will also give a little added rigidity to the floor you're installing, as well as some sound and vibration dampening properties. Cut a piece to go in between each rib, then, install the floor.

With foam board, the water will drain better than it would if you used the pour-in or blown foam.

It can be done either way, by attaching to existing ribs, or building it up some with framework. If you go to the existing ribs, it looks like you're going to be limited to 3/4" or less, for the thickness of your board. Building it up with framework would allow for thicker material, like 1 & 1/2"

Thanks!

I agree with PSG. I think you should build up the ribs though partially because they are round. If you screw/rivet into flat material it will make it a little more sturdy and less likely to flex and pop rivets.

The foam will help support the floor if you build it up right. With the slight v-shaped bottom glue in blocks of foam to the foam to help support it near the center because it will sag over time. Just my 2 cents