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There's a fair amount of information concerning the sail. The corner of a piece of woven wool like a blanket was found in the attice of a church in Norway, IIRC.
Of interest is that there is an "eyelet" or opening woven into it. and, again because I'm lazy and not looking at sources, I think it's dyed red. The red die of the time was made from madder root. The piece of fabric is very rough and thick. Looms of the time were as large as a meter wide, so the sail could have been made up with long meter-wide vertical panels.
It would have weighed a lot, and smelled like a wet dog.
great work.
Bill