Foam board insulation and vibration?

Quicksilver has a foam sandwich floor. Ribbed 16-gauge steel with 20 gauge flat factory spot welded. The original floor. 2"x1" teak stringers were used full length as longitudinals. Every four feet cripples were laid. Nothing but Franklin Tite Bond was used for the longitudinals and cripples. 3M spray adhesive was used to prevent noise squeaking of the insulation when flexing was borne by the foam. Then half-inch laminated plywood teak (marine tongue & groove) flooring was laid. Adhered to the stringers with Tite Bond and to the foam with adhesive spray. Concrete cinder blocks were used for compression clamping during the 2 day adhesive "cure". Salvaged marine through-fittings were used to pass pipe tubing and electrical.