Center seating

If I wanted pedestal seating for the oarsman how should it be supported so that there isn't a giant point load in the middle of the floor. What I imagine is an elongated front to back oval to allow the oarsman to shift around a bit fore and aft and also to store 2 or three 12 vt batteries. As a big clumsy oarsman I find it hard to negotiate up and over the seat. It would be nice to just spin around a central seat. Thoughts?

Sounds good. You could make a form and laminate it out of thin strips. Mount a tractor seat on it.

how to support the pedestal though? The way it is right now the sole and sides equally divide the load. If I go to pedestal seating and make no additions there would be a significant point load right in the middle of the sole. Remembering that I'm 265 plus and then 2 batteries at 60 ea. Without extra support I'd be fearful of ripping the tabbing along the sides, lengthwise.

It will hold. I pronounce it.

If you make a square pedestal make a 2-1/2" thick block that fits inside the open bottom of the pedestal.
Make it 1/4" less than the inside measurements.
Glass all sides except the bottom.

Make sure it still fits inside the pedestal. Maybe 1/4" inch less wasn't the right amount.
Glue it to the bottom of the boat with epoxy putty.

Now you plonk the pedestal down onto the block. And bolt it there. If something breaks it won't be the bottom of the boat.

......and put the batteries into that.

Okay. Once the weather warms.