Back in 2003, retired Admiral Stuart Platt and sailor Mark Ott, formed The Harbor Wing Company after dreaming up a breakthrough concept of an unmanned computer-controlled wingsail on a stable sailboat, and it was not long before they had one of the world's top experts on wing sails on their team—Dave Hubbard, who designed the rig for America's Cup winner 'Stars and Stripes' plus many others before and since, including the latest AC72s. With Admiral Platt's connections, they soon had the US Navy interested and perhaps it was no mere coincidence that they test sail out of Pearl Harbor, Hawaii!
What they have achieved since that time is both fascinating and remarkable. Here is a film of the demo that was used to convince the skeptical of their success with a 30ft prototype. The vessel type is officially called an 'AUSV'—or 'Autonomous Unmanned Surface Vessel'. www.harborwingtech.com/products_demo.htm
This prototype has a 14ft beam and a 40ft wingsail with a single pair of control fins.
In order to have control in a greater range of winds, they have since split the wing sail into two parts with a separate set of trailing control wings on the upper section, so that in high wind conditions, the upper part can be depowered for improved control, stability and safety. This concept is now known as the WingSail™
Since 2009 their plans have expanded and they have designed a 50ft commercial trimaran (X-3) that will have the split wing design, and this concept is one that might even reach across to the recreational sailboat—initially at least, on a multihull platform. It was a natural fit that famed multihull designers Morelli & Melvin would become involved with this design. As this new boat is also planned with hydrofoils, it's also not surprising that this already formidable team has brought in Dr Sam Bradfield, an expert who has been successfully playing around with and on hydrofoils for over 35 years. The first X-3 is now being completed for the US Coast Guard, 'for surveillance of marine natural sanctuaries', and Homeland Security is no doubt taking a long look at this development for further surveillance duties, possibly linked to unmanned surveillance drones etc.
As pleasure sailors start to get more comfortable with having a rigid sail up at all times, we might indeed see this technology slowly grow into the recreational field. It certainly has some capacity to save a percentage of fuel costs on merchant ships but that will depend on the balance of 'cost & maintenance' versus 'predicted fuel cost'.
(This is something that has been around for a long time as I remember attending technical papers on this subject in the 1970s, and the Maritime Division of the US Dept of Commerce followed this up with an extensive 270 pg study prepared in 1981 by the Wind Ship Development Corporation, then of Norwell, MA, that is still in my bookcase. Their rotating 'SpinSail' was then featured in a cover article of Popular Science in 1984, a concept based on the Flettner Rotor invented back in 1922, with an early rotor-equipped vessel even crossing the Atlantic in 1926! You'll find the PS Jan '84 edition on line (pg 70) if you want to learn more on how the Flettner Rotor works through the Magnus Effect. In Europe, this concept is still being promoted and there are a few ships even using it commercially.) The latest Cousteau Research boat also used a version of the Flettner Rotor called 'TurboSails'. See pic
As my principle aim in briefly covering this WingSail™ concept here, is to make sure this work is not totally overlooked by my readers, I now refer you to their website, from which you can learn more and stay up-to-date with the latest developments.
Footnote: I have just noticed that Multihulls Magazine Jan/Feb 2013, is currently running an article on this development so this could be a source for another perspective.
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