Martin, you must be using very thick/dense ply (or light scales ! ) Here are
my seat component weights.
Base ply 308 g (6mm)
Back ply 391 g
-----
691 g (1.5 lb) 3 lb the pair
2" foam back 459
" seat 351
------
810 (1.8 lb) 3.6 lb the pair
Covers 150 g (0.33 lb) 0.7lb the pair
Total 2 seats ............................... 7.3lb
(except for the bridge strips below, glassed in beyond weighing now)
I originally intended to back the lightweight foam with a denser variety but
headroom for my giraffe type frame precluded this. Anyway it weighed in
nearly twice as heavy as the foam above so would have added another 6 lb. So
it's better to get the backup (bottoming ?) spring from a thin ply than a
layer of denser foam.
Foam idea sounds good though as long as it doesn't crumble with time. But
you lose a place to store emergency rations, valuables etc., (and a place to
lose nuts/bolts and spanners (:-))).
Graham C.
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