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Sea Transportation: Big Ships Back Under Sail
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October 15, 2008: The rising price of petroleum products is making wind power practical again for merchant ships. A century ago, sail powered merchant vessels were fading fast, replaced by faster, more expensive, but more economical (because of cheap fuel), steam powered ships. But now that has changed, with advances in sail technology and rising oil prices making it cost effective to resume using wind power. For example, the U.S. Navy recently chartered a 400 foot, 20,000 deadweight ton merchant ship (the MV Beluga) to move some cargo. This ship was one of the first equipped with the SkySail. This device looks like a large (160 square meters) kite, flying 100 meters in the air in front of the ship. What this rig is doing is actually pulling the ship, reducing the use of the engines, and saving over a thousand dollars a day in fuel costs. At that rate, SkySail pays for itself in less than a year.

About 60 percent of the worlds 100,000 merchant and fishing ships can use SkySail efficiently. The equipment is computer controlled, and weighs only a few tons. Not much training is required to run the system, and smaller warships could use it as well. Depending on wind conditions (which vary greatly across the oceans), ships can save 10-50 percent of their fuel costs a day using SkySail.

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CJH       10/19/2008 4:16:25 PM
The age of sail ended partly because steam ships required fewer crew members and less training/experience amongst the crew.
 
Of course now we have automation,  robotic technology and advanced materials. Imagine a computer actuated sailing ship with lots of carbon fiber and titanium.
 
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doggtag    21st century sailing: not your great-father's 12-knot schooner anymore   10/19/2008 5:37:03 PM
The SkySail is so new and revolutionary, as of yet there isn't a good homepage up for the company (was still under contruction).
 
So, luck has it that Popular Science magazine has the goods on it,
even though their magazine had its article on the SkySail some months ago.
 
{   ht*p://www.popsci.com/category/tags/skysail   }
 
Yes, with today's automation and computer control, the system has proven to self-deploy and recover with minimal direct human intervention (providing everything works as it should).
Certainly has a lot of potential, especially considering it's quite scalable to larger vessels (but wouldn't count on seeing it pulling along a USN destroyer anytime soon!...)
 
Despite sailing generally being looked at as "antiquated" technology at least as far as the 21st century is concerned,
there is still a lot of interest in high performance sailing, and using the latest technology has to offer to take wind powered ships into areas early man never dreamed of.
Case in point: the Volvo Open 70 70-foot racing yachts have recorded speeds, by wind power alone, of 39 knots!
(another link courtesy of Popular Science...
{   ht*p://www.popularmechanics.com/outdoors/boating/1681731.html   }).
 
Now I don't see us returning anytime soon to three-masted schooners and other wind-powered ships that rely solely on wind power for propulsion (at least not for anything other than expensive pleasue craft),
as there are instances when there is a dead calm about the waters and a given commercial cargo vessel may travel even a few days at sea without any noticeable wind.
 
Also, a lot depends on the fact that a wind blowing the opposite direction you want to be going in isn't going to help much,
at least as far as typical sails are concerned.
 
In those such instances, we can borrow an idea from the legacy of Jacques Cousteau, whose ship the Alcyone was equipped with two turbosails that used wind moving around a curved vertical airfoil section that effectively works somewhat like an airplane wing or helicopter rotor, but assists in pulling the vessel forward rather than up.
 
The main shortcoming of the turbosail design, unlike the SkySail, is that the turbosail is always there, taking up valuable deck space, wheras the SkySail can be fully retracted into a compartment and is out of the way when not needed.
 
There have been numerous incarnations of airfoil designs replacing standard "soft" sails in sailing vessels.
One of the most infamous (depending which side of the race you were on) was in the winged catamaran Stars and Stripes which was used in the 27th America's Cup Challenge in 1988.
Working just like an aircraft wing, the sailfoil on the Stars and Stripes worked moreso by creating forward lift (or more accurately, pull) even in head-on winds, whereas normal sails catch the wind from behind to do the most working in pulling a ship forward (if I'm understanding that one description correctly).
 
But rigid wingsails (sailfoils), just like turbosails, still have the disadvantage when compared to SkySail, where these rigid designs are always there sticking vertically out of the ship, unlike SkySail's retractability when not needed
(which is a primary reason why the turbosail never fully caught on with the worldwide commercial shipping designers,
as these rigid sails would've encumbered the operation of pierside shipping container cranes and other cargo gantries).
 
However, sailing tech isn't done yet: a Turkish design team is in the process of creating a nautical X-craft (almost literally) called Volitan  (link also courtesy of Popular Science
{   ht*p://www.popsci.com/environment/article/2008-06/sun-powered-sailboat   }),
wh
 
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