View Full Version : Omer Wing Sail

12-05-2011, 04:38 PM




"Mark III is based on a new concept of a free standing "A frame" mast. The wing shape is made by two main sails and one leading edge sail.
Once all of them are hoisted, we get a variable geometry wing that can be reefed."


"A free-standing, rotating carbon fiber mast, is fixed to the boat (at the same location of a standard rig) by a ball at the bottom and a roller bearing on deck.

The airfoil shaped wing is made of conventional fully battened sailcloth, and is attached to the mast at about 25%-30% of the airfoil's chord length (meaning that 25% of wing area is fore of the mast).

The wing is made of three different sails - Two main sails aft of the mast, and one leading edge U shape sail fore of the mast. Each of the sails is hoisted and reefed independently.

The sails are hoisted along tracks attached to the "legs" of the mast, at both port and starboard sides (see picture No.4 in the gallery). Once all three sails are up - you get a wing.

The A frame mast enables hoisting the fully battened U shape leading edge sail, and keeps the right distance of the wing's port main sail from the starboard main sail.

The bottom of the leading edge sail is fixed to a U shape piece of carbon (kind of forward small U shape boom). The wing's trailing edges (the leech of the two main sails) are attached to the boom like any other standard main sail.

A small electric or hydraulic ram induces wing's camber by changing the angle between the mast and the boom. Since the camber is induced by the boom at wing's bottom, the wing's trailing edge is spontaneously twisted to a "0" camber (symmetrical airfoil) at the top of the wing.

When the wing is hoisted, the mast and the wing rotate spontaneously (weather-cocking) into the wind.

By slightly sheeting in to 80-100 Angle of Attack, off you are..."

Sanity Check
12-06-2011, 08:16 PM
Wow. Really interesting post and idea for a wing sail.

I am, though, not sure I understand about the sail being reefable as three distinct sections. My guess is that despite this division between sections, they are nonetheless intended to always be used with identical reefing levels... and I'm still not getting a clear mental picture of what intermediate stages of reefing would look or behave like...

Reminds me of Phil Bolger's "100 Small Boat Rigs" wherein he describes a variety of designs and expains the advantages of staysails over sails with turbulence-inducing spars at their leading edges; likewise the relative advantage of "sock" type mains such as on Lasers.


From my experience sailing with a free-swinging unstayed rig - the lateen setup I made for my dinghy - I can tell of the strange characteristic when sailing downwind with the sail out well past 90 degrees as seen in the picture: the sail acts as though it is on a boat going upwind in the reverse direction and the boat heels to windward. Also, when the sail is weathercocking spontaneously in blustery conditions it can cause the boat to oscillate wildly as the motion of the boat's rocking and the swaying of its boom feedback on each other.


12-07-2011, 11:02 AM
Would be interesting to see/demo a unit in real life.