John...Ooh, lovely post to reply to.
Foam.....yes, I did discuss it with my inner self and rejected it for reasons that may well become clear.
It may well be a "good" material in some instances. But I have (as always) other thoughts.
For a start...re-read MS84 again and you may well discover that only the inner layer of planking was diagonally laid. The outer one was fore and aft. And this is what I'm trying to replicate. I also believe that the outer planking was 4" wide, which makes my choice of 3/8" pretty reasonable.
But this is a "plug" I'm making...not a "plank on frame" model. So, being aware that even on such a prestigious vessel as an Admirals Barge, there would still be indications of some plank landing edges. So it's my desire to at least give a hint of those landings on the eventual hull. It may work, or it may not.
As always with my models I'll be going down the GRP route. Strengh, longevity and all that. However, if the hull was to be a varnished and shiny one then perhaps, just perhaps, I could rustle up some long forgotten and unwanted skill to make one. Until that day arrives I think that GRP is the answer. For me, anyway.
BUT for whatever reasons you are reading this build, I'm grateful...even if it's only a dispute. Bryan.