Got the same problem too. But with your info I finally, found out that it is from Oct 1979. I believe it is a N27S based on the cabin configuration but the sail says N27. I am about to buy a new mainsail and was wondering about the dimensions. My measurements of the old sail were 31ft and 9.5ft (foot) but all rigging
configs show 10.25ft foot. I am pretty sure the boom would support 10.25ft. Just wanted to make sure.