I used seadek flooring on my 2005 340 in the cockpit area and the swim step. It feels good to walk on and is great for nonskid safety. I used 6mm which is fine for what I wanted. I understand it also comes in 8mm thickness which would provide more padding. Probably would be good to evaluate both thicknesses.
Not sure of longevity of this material on the swim step being exposed to sun.
