After much thought and with some shared ideas in this forum I built a simple seat with some 12mm marine ply and a couple of batten’s It e we irked well this week sailing up the East coast except my crew wants it padded !!
You can post links to photos hosted elsewhere. (They will be seen by forum readers as normal.)
Unfortunately the forum has reached its image memory limit, and for the moment new photos can't be directly posted on the forum.
I hope the current image posting problem will be solved before too long, but with a lot of other things on my plate I haven't had time/headspace to sort it out yet. It may involve e.g. paying a subscription for additional memory, deleting all/most existing photos, or setting up a new forum on a different host/software. (There are additional complications too tedious to explain here.)
Photo of simple LM30 stern seat on Lone Star - made of 12mm marine ply and Meranti battens - the upright panels are clipped to the stern rails with u shape clips - the load is taken by the panels to the deck the clips are only there the panels in the right place, it seems to work well so far.