When I added the floor to my 1860 Landau in 1998 I used the blue board foam sheeting like used in residential housing ... but I stacked the pieces vertically between the ribs so that water could still get to the boat hull strakes and make its way toward the transom drain hole ...
That blue board sheeting is still in as good a shape as when I installed it in 1998 ...
Plus ... it’s easy to remove for working certain tasks ...
Rickie
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