I deem my cooler project finished! I cut and fit pieces of the 2" Styrofoam to seal up the lower section beneath the bench. spray foam was used to fully seal all gaps and edges. then I sewed up a covering from the same material used for the boat cushions, and used a bit of super 77 spray glue to attach it to the sides of the portion of the box that's above the bench. for the cooler top I also cut a piece of the carpet runner material and sewed that onto a cloth edging. the foam top piece is attached to the hard cooler lid with several large pieces of velcro, so the lid lifts as one, as it should. We stayed 3 days on the boat a week or so ago, before the lower portion was even finished, and the two 1/2 gal jugs of ice still had over 1/2 their ice when we got home, so I guess it works .