I put together a Navigator’s seat frame using stainless bimini fittings and 25mm stainless tube.
The Sheridans offering was out of stock with a long lead time (and I don’t think it looked that nice). The parts came to around £200 and making the re-inforcement board was probably the most technical part. I’ve still got some finishing touches to do such as plugging the holes for the board fixing screws and a few minor tweaks. The framework is held together with grub screws in the fittings. If they end up slipping, I’ll have a stainless fabricator weld and polish selected fittings.
The seat was an old original Freeman one which still has some life in it and the whole thing separates and stows with the hinge fittings using spring-loaded drop nose pins for easy removal.
The wooden plugs to cover the panel mounting screws still need to be glued in along with a few coats of varnish.