312/320 Helm Seat modifications
By far my least favorite part of the 320 (and 312) is the helm seat. The front edge of the base cushion is too close to the steering wheel. It looks out of proportion, and you can’t stand up that moment to look over the windshield without ejecting your First Mate and flipping up the bolster. The seat back rides unfriendly surfaces on the wet bar countertop and gets marked up and cut. The storage under the helm is an ugly open space generally full of cleaning supplies, flashlights and junk fully visible from the salon.
I made some simple and inexpensive changes to the seat back mounting which let me move the cushion back an inch which is more substantial than it sounds. Now I can actually stand at the wheel without moving the bolster for short periods. It’s a straight forward project if you are comfortable with stainless steel staples, stainless steel T-nuts, a drill motor, a countersink bit, and some needle and thread. I moved aluminum seat back bracket attachment from inside the seat back plywood to outside or behind the seat back plywood. I haven't done anything where the seatback bracket meets the cushion, but that might come later. The modifications moved the seat back an inch forward relative to the seat cushion, and lets me move that cushion back an inch on its track. The project required drilling out and countersinking the tapped holes in the aluminum brackets, adding stainless T-nuts inside the seat back, and clearing a bit of wood to nestle the brackets into their new position. I sewed up the holes in the vinyl cover, and cut clearance in the seat back closure panel for the 1/2 inch aluminum. Photos also show some 1/4 plywood added to the seat back as a spacer to keep the seat back looking correct. 1/2 aluminum covered with 1/4 plywood would have left bumps, hence the 1/4 inch plywood spacer. I also re-drilled the aluminum seat track mounting holes to keep the nasty hardware under the seat cushion. The carpet touches on the seatback and under the cushion match my replacement carpets made by Snapincarpet.com and made a nice buffer where the seat contacts the wet bar countertop.