Maybe, although I haven’t seen anyone doing it. I’m guessing you would need a sheet to each corner to trim the sail tightly enough which I think would be too much of a headache for the crew. Worth thinking about tho, especially in a castaway situation!
I think the square rigged sails could be rotated, so you could sail with a cross wind. You would just have a fair amount of trouble sailing upwind.
Maybe, although I haven’t seen anyone doing it. I’m guessing you would need a sheet to each corner to trim the sail tightly enough which I think would be too much of a headache for the crew. Worth thinking about tho, especially in a castaway situation!