Replace foam n floor on bubbledeck

I have a "70" wreidt jet boat. I've already pulled the old floor n water saturated foam. I'm planning on replacing the floor with MDO plywood. I want to use pour in#2 marine foam. My goal is to create floatation as well as noise reduction. Is it possible to pour or inject the foam through holes after the floor is epoxied in in order to fill every void and add rigidity to the floor and reduce sound and vibration? And after glass n fill the holes. Or should I pour the foam and sand it perfectly flat where the floor could be in contact and glued to the foam underfloor. I'm looking for a quiet n fast machine. Got a 454 Gen 6 for it n need guidance

 

Welcome to the forum.

You can do it either way, though pouring first will insure every area is completely filled with foam. The trick with pour in foams is being able to get it in quickly, as it expands fast, so you don't have much time to play with it and most importantly, having enough air escape holes, so the foam doesn't bulge out the hull in places, which is can easy do if it doesn't have enough air and foam escape room, under the sole (floor).

For the novice I'd recommend pouring first, waiting a day or two for it to fully cure then using a hand saw (yeah a regular old cross cut saw) to knock off the major ooze out areas and smaller blades to fine tune it flush with stringers and other supports. This will leave you a rough, but flat surface to bond down the sole piece(s). Do some basic math and figure out how much you'll need for each compartment. All of these foams have a specific expansion rate, for example a gallon of 2 pound foam will usually make about 8 cubic feet. Roughly figure out how much area within each compartment, so you don't have foam oozing out the top and wasting a bunch of "muffin top" foam.