I seriously doubt that 1" foam would hold up on it's own for long. Under pressure, it will flex in the middle, which will cause it to pull away from the hull/deck at the edges. Sandwiching it between a couple of layers of thin ply or strips - leaving just 1/4" or so of the edges exposed - would help, but even then, the bonding surface is still pretty small.

What's your rationale for using foam instead of plywood or strips? Are you just looking for flexibility during impacts?