I made a mold of closed cell foam then topped it with a 2x12. Drilled a few holes and poured some two part foam in. Once is was dry and stabilized I used some stainless steel L channel and screwed the 2x12 to the bulkhead and stringer. On top of the 2x12 I used some shop flooring pad under the battery box. The pourable foam underneath will conform to the hull so there is no way it could damage the outter hull, but it will also hold up the side near the step down. I didn’t screw in that side.

Good plan. Thanks for the insight..