John,

This is a common mis-conception.

The truth is that most merchant vessels could do only do 160 deg between
tacks, but many other square sails could do well better than that. It
just took a lot of manpower and money to handle the extra rigging that
would tighten the luff. Vikings with wool sails reports taht they could
manage about 120 and that was not equaled until the fore and aft
rigged schooners appeared in the early nineteenth century.

Matt Colie
Lifelong Waterman, Licensed Mariner and Perpetual Sailor


John Weiss wrote:

Square-rigged boats could sail no higher than a beam reach. However, the sails
were not flat, and they were trimmed appropriately to allow the boats to be
sailed other than dead downwind.

I don't recall the date triangular sails were invented, but they were the dawn
of upwind sailing in the west; junk rigs enabled upwind sailing in the east.

"Axel Boldt" wrote...

Thanks a lot for the illuminating answers. I read somewhere that the
"sail-as-airfoil" trick is a rather recent one, and that formerly
people would just let the wind push them around. Is that true, and if
yes, how recent is the invention?