My comments below:

: The historic kayaks are so old and were intentionally lightly constructed,
: the best you can really do is make an educated guess to their orriginal
: shape.
: Bill H.

Actually some kayaks that have been stored for hundred years are in pretty good shape, some doesn't seem to have almost any bending. In this case the Illorsuit kayak was build in 1959 and surveyed about 5 years afterwards. It's unlikely there's any damaeg done in such short time.

: Oh yeah, as someone else that right now I forget said, these boats were
: designed for 5' tall 100 lb. people. Since few of us are of those
: dimmensions the orriginal designs need a bit of modification if we intend
: to actually try to paddle them. So the boats can't really be to exact
: historical dimmensions anyway.
: Bill H.

For Illorsuit this issue is easy - Both famous (for western people) Illorsuit kayaks are made for two persons - Ken Taylor and John Heath. Ken Teylor's Illorsuit drawing has the waterline set at "carrying 150 pounds", I guess that's about his weight.

For other kayaks its a bit tricky subject. I tried to ask about the issue at qajaqusa forums, but no real replies there. However the newer kayaks are made as small as the kayaks historically. The KOG has several kayaks from 70's - 90's if I remember correctly. Those kayaks are not larger than the older ones. But like I said it would be nice to know with weight person some kayaks are made - now it's just a guess.