Theory of Winged Sails

What do sailboats and airplanes have in common? They both rely on airfoils to generate lift!

Sails produce lift in a horizontal fashion while airplanes produce lift in a vertical fashion. Now, if airplanes and sailboats are both using airfoils to generate lift, why do wings look so different from sails?

Well, the answer is complicated. First off, they really shouldn’t look that different. Airplane wings are “wings” because that shape produces more lift and less drag, making it a much more efficient system and thus has been widely adopted on all airplanes.

Sailboats struggle with a thing called “Traditional” which is a nice way of saying “I won’t put that newfangled gizmo on my traditional boat!”

As a result, airplanes moved on to wings instead of sails long ago but sailboats remained in the past.

The only word strong enough to break tradition is “racing” and winged sails have burst into that scene with fury due to their incredible boots of efficiency. A wing sail will generate many times the lift of a similar sized sail, meaning that the same surface area can be used to produce more power without increasing weight, and as a result, greatly increase speed.

Hull speed was a global governor to sailboat speeds, which halted the desire for super-charged winged sails, as there was no way to exceed this speed limit. That was until foiling became commonplace on racing yachts, where this added power means insane top speeds! The only way to be faster than your competition is to have a better sail, and so the arms race of sail design is back on and winged sails are leading the pack.

The reason winged sails haven’t been fully adopted by every marina dwelling racer is the issue with stowage. Sails can be furled or flaked, winged sails are somewhat of a structure, and stowage of them is rather complicated. Until this aspect gets ironed out, winged sails might not be an option you can check the box next to on your new yacht at the boat show; but give it time.