this was for the Express, bolted to flanges extending down from the coaming. I made one for the NorthBay but the seat was a lot shallower in that low decked kayak. The forward edge of the seat is rolled down about 3/8" providing rigidity, minicell blocks are glued to the outer thigh area under the seat and directly under the seat, there's an area just big enough for a shallow (2 1/4"?) pelican box to fit 1/2 way under the seat, or a hip throw bag. I cut a hole big enough for a pump to fit inbetween the thighs through the seat for pumping water. With a couple of webbing strips attaching d-rings just forward of the seat on the bottom of the cockpit and under the seat there's a webbing of 3/16" bungie to hold stuff under the seat and about 6" forward. The seat is very comfortable and reduced the pressure on my knees/thighs a lot for the same amount of lean. I could imagine making a minicell seat then going back to carve out areas for framing a small box within for access to gear. The amount of underseat room available is probably also dependant on how high the foredeck is to afford the higher thigh angle.