Blue or Pink Foam Board in Semi V

I am trying to figure out the best way to put the foam in the floor between the ribs of my bass tracker. My question is how close do you guys cut the foam to fit. Lets say the shallowest part of the V (closest to the side) is an inch and a half, do you just run an inch and a half thick piece of foam from one side to the other and leave an empty void under the foam in the middle where the v is deepest? or do you cut the foam at an angle and try to fill every inch of the v with foam? I am hoping to get some support from the foam so I can go with a thinner plywood to save some weight.

Thanks for all of your help guys I appreciate it as always.

My boat is a mod-v, so not as much of a V as yours. But for mine I ended up using 2 pieces of foam under my floor which filled the space between my ribs perfect right up to the top of the ribs. Where my hull started to take on the mod-v shape, I used 3 pieces. The third piece I hacked up pretty good to get it to fit as best it could. Wasn't perfect, but better than just throwing 2 pieces in there.

I think it would be frustrating to try to cut the foam such that it filled the space under the floor completely. I plan to light sculpting to the foam but it won't fit perfectly against the V shaped floor. I think the empty space would provide space for water to be able to drain to the back of the boat more easily, allow a bit of air circulation and minimize foam sitting in water where it will eventually get waterlogged.

I agree with 1lhorn. Leave some room for water under the foam. I'm putting new blue foam (from Lowes) into the bench seats and under my deck when I replace it in the next week or two. I would highly recommend using the 5-ply (thick) for your deck. Its not that much heavier than the cheap stuff and will last a lot longer.

Not sure how the chines/channels in your boat are, but mine run from the tip of the bow all the way back to the transom. Unless your cramming foam into the chine/channels in the "V" portion of your hull I don't see how it would trap water. Just like in the flat portion of your hull the foam will sit on the hull bottom, but above the chines/channel which allows water to freely get back to the bilge. I routinely get aluminum shavings, rivets, wire insulation, etc. washed all the way back to my bilge after doing work on the bow of my boat which has access to the hull bottom. Things like that get dropped while doing work, but still make their way back to the bilge via the chines/channels. I've had my floor and foam installed in my boat for nearly 2 years. It gets TONS of dirt, sand and mud in it, especially during waterfowl season. But I have zero issues with my hull bottom and chines getting clogged.