quote:
Originally posted by geoschmo:
A ship with a square sail and a keel or rudder can follow the wind or go at angles to the wind (but still with it) because the friction of the water against the keel or rudder will keep the ship from rotating.
A ship with a triangular sail can go into the wind at angles by aerodynamic principles similer to how a wing on an aircraft generates lift.
Actualy ships with square sales can sail up wind like ships with wing shaped sails. the difference is that they just can't get quite as high up (i.e. closer to the wind). This is called pointing. Most modern keel boats can get to within 30 degrees of the wind when beating up wind (zig zaging up wind). The older square sailed boat usualy managed 45 degrees or 60 degrees (including the drift). The thing to remember is that even with a square sail, you could turn it around the mast and have one part of the sail near the bow and the other part near the stern. This allowed you to point the boat at less than 90 degrees to the wind and still catch the wind. The shape of the sail is inefficient for this but not ineffective.
Strangeone. (who was a sailing instructor at one point in his mis-spent youth).