usage of sails for large vessels

Using sails can the ship of huge displacement be propelled in calm weather?
we are looking to install a foldable automatic sail on large vessels to reduce its fuel consumption and increase its efficiency by 20-30% .
The sail must automatically install itself in calm weathers and must be propelled only by it . And during rough weathers it must close down.

DELIVERANCE is such a vessel . what we're looking for is an advanced version of this prototype.

 

In calm weather there is no wind, so the system won't work. It may be useful in heavier weather.

 

You need to talk with these guys:
http://www.skysails.info/english/skysails-marine/

but you wont get 20-30% from any system.

However, the obvious flaw, as Gonzo noted, calm weather = no wind. No wind = no assistance = no savings!

 

Somewhere on Boatdesign net is a thread or threads on the subject.

Sails to propel the vessel are a pipe dream...sails to assist a motor driven vessel are worthwhile .

The threads concerning this had links to scholarly studies on the cost benefit of sail power.

 

When I was a kid, one of my dad's regular rants was that for non-perishable goods, sailing vessels could still be viable. His general thrust was that the extra time would be balanced out by the lack of fuel costs.

But I doubt it occurred to him that having money tied up in cargo for a long time is expensive in itself, because of the slow return. Money tracking the winds across the ocean isn't earning interest, or being invested in the next cargo.

I suppose an individual operator, with his own ship and no debt load, might be able to find a niche where he could make a living -- especially if he were captaining his own vessel. After all, lumber schooners plied the the Pacific coast well into the 20th century, with the last purpose-built one being launched in 1905.

Interesting side bar: those lumber schooners were built from the same wood they carried. They had Douglas fir (Oregon pine) frames, planking, decks, cabins and spars. And judging by the rosters they were heavily manned by Scandinavian crews, who seem to have faded into oblivion along with their ships.

 

even in calm seas, there'll be considerable amount of wind enough to propel the ship of dwt to some extent!
In extreme weather condt's, maneuverability will be a tough task
thanks for the reply..

 

like he suggested, calm weather = i dint mean like terribly calm, if there are waves, there must be wind, so it is possible!
and the eff part, even if its 5-10%, would save huge sum of money

thanks for the reply..

 

thank you very much...

 

Obviously you have never been rolling and pitching in a dead calm for days. What is your experience at sea?

 

Most sail deployment systems have been tried.
The "Flettner Rotor" may be what you seek, as it is a power-assist device, intended to assist a ship that is powered at all times, and could give the savings you require.
This thread is "random picture".

 

To what angle to wind does rotors provide forward motion? I would hate to tack in a freighter.

 

no one has made sail assist commercially viable in any large scale. you have two problems; the cost of installing and maintaining large automated sail system vs. the fuel you save by using it. Usually not worth the cost, burning diesel fuel usually less costly. The other issue is utilization of the vessel, to make it take longer to reach a given port (to take advantage of favorable wind or sea conditions) means less capacity to deliver cargo. IOW, the longer it takes to deliver load of cargo, it means the less total trips the ship can take over its useful life, means less total income off the investment of buying the ship.

That is why, for the most part, sailing has been reduced to either sport or recreation since the invention of fuel driven power plants for ships.n There may be a few isolated routes where it can be made worthwhile, but not in any widespread commercial applications.

 

http://en.wikipedia.org/wiki/Rotor_ship
http://www.thiiink.com/
http://www.thiiink.com/history-of-flettner-rotor/
One company at least claims to have something to cover your needs so maybe you should call them up.

 

That's really clever, aerodynamically it works just like a curve-ball...

 

So it can't sail into or out of wind? So it is best perpendicular to wind?