Chiming in on this three months later. I'm also interested in building a hard deck for my FC470. I currently have the roll up floor. Anyone ever get around to successfully making one on this thread and care to share or PM the specs? I'd love to have a hard deck to support my 55hp Johnson Enforcer.
"The FC-470 can be used for over-the-horizon transportation, inserting lightly armed raiding parties or reconnaissance teams onto beaches, piers, offshore facilities and larger vessels."