With my most recent Sunfish purchase last month, I hadn't had a chance to examine this 1971 Sunfish's sail.
Yesterday, examination showed a silky all-white sail with about 15 holes . It risked a major tearing, but I took it for a spin anyway, with a variable wind from 1 to 7-MPH.
Labeled Ratsey & Lapthorne, it appears to be the original sail. Comparing it with my crinkly Intensity sail, what stood out right away was how "unflat" it was. There must be 6-inches of draft at the tack—and pulled the Sunfish remarkably well—noticeably well!
Some debris will wash off the sail, but not sure how I'll fix the holes. The edges of some of the holes are seared. Stored downstairs, it appeared as though someone emptied the contents of a charcoal grill on it from upstairs.
I've photographed a close-up of the Sunfish logo, so might print 15 little Sunfish templates to make sail-tape patches in a contrasting color.
Ratsey Lapthorne did supply the early Sunfish class legal sails for years. I recall they were an English company with a loft in City Island, NY (?) So, yeah, I think you have an original factory issued Sunfish sail, and a pretty knarly one at that!
Fun! To repair it I'd suggest adhesive backed insignia cloth. Sailrite makes several colors. You could by samples, they are about 3 inches square, or buy a yard
The vintage sails had a red and blue stripe at the peak, very simple but it looked nice.