You have a better sense of the proportions but when I extrapolate from a screenshot found on the making of the Sol video there is little encroaching on the prime use portion of the bunk - a mere 15 degree rotation of the bed solves that. And the part lost under the seat is probably not prime storage volume.
I also do not understand the requirement for beefing up the internal structure: fixating the original lower beam requires a hole and a lashing as you explained; with the higher beam there are just two holes in existing walls (and no hole in the hull ;-)
Is there a difference in the stresses if the beam is above or below the bridge deck?
--- In harryproa@yahoogroups.com.au, Rob Denney <harryproa@...> wrote:
> ... Putting the beams on the bridgedeck would have
> required more internal beefing up and made an already small bunk smaller.
...