Looking for help with an outfitting question. For kayaks with hard plastic seats bolted to the cockpit rim, should the seat hang unsupported above the hull? Or should the seat rest entirely on the hull with the hangers just used for positioning? Or maybe something in between if possible to fine tune? If some or all of the weight is taken by the hull, what material you would put between the seat and hull to spread the force or prevent abrasion? Thanks.
combo
it should be a combination of hanging and resting on the hull. This gives MAX security from shifting side to side/ fwd/aft.
some closed cell foam works as a pad.
steve
Doesn’t matter
Seats can be placed directly on the hull, at least on composit and stitch and glue boats. Don’t see a problem with plastic ones either.
Do what ever feels good 
By custom, in composite WW kayaks
the seat would hang at least half an inch above the bottom of the boat. One reason was so the hull could flex without being damaged if one went over a rock, log, or ledge. If the seat waggled from side to side (which could be avoided by proper design of the seat sides) then one could put some foam in the SIDES of the boat to prevent waggle.
Composite layups do not stretch if they include enough glass or carbon, and stretch little even without glass or carbon, so humping over things will not produce oil-canning. Poly kayaks, on the other hand, are made of a material which stretches easily, so letting the seat contact the floor in the proper way (perhaps including some added foam) may sometimes reduce the amount of stretching, and the amount of permanent oil-can deformation.
hanging unsupported —
seats which hang unsupported tend to ultimately break at the point where the seat sides are fixed to the cockpit rim. that’s why the vast majority of composite boats have the seat fixed at a point about 2 inches off the hull of the boat and actually sitting on closed cell foam. the foam takes the weight and stress of your shifting weight and the sides of the seat keep it if position front to back.
Maybe they do that now, but for decades
composite boats were built with truly hanging seats, and there was no breakage of the sort you describe.
weight
if we were to build a true hanging seat, it would have to be quite strong, thick and heavy. The ol’ school ww boats of yesteryear did have hung seat that were quite sturdy.
The reason we brace them in more than one place is to have a lighter material, braced often.
steve
decades
true, but for decades, boats weighed considerably more than today’s boats. today’s lighter materials require more bracing and support. witness the plethora of ‘broken seats’ in NKK Explorers (for example only - not meant to get into another one of those lengthy NDK diatribes) in the past due to poor support and too much ‘hanging’.
Sorry, guys, ww slalom boats are still
made with free-hanging, carbon seats. Nineteen pound slalom boats.