Cargo Sailing Ship: a near future reality?

I'm planning building a Flettner rotor from 50 year old drum shells.

 

If you could back this up with some data, examples, industry trend stories it would be of great value.

A large number of ports have had extremely attractive natural gas prices for nearly a decade now and to my knowledge LNG shipping is just getting started while nat gas power of ships is not even foreseeable. First LNG shipping will transform worldwide natural gas prices, then shipping will make it's investment (motors are easy vs safe storage). My projection is that natural gas prices approach BTU parity with oil and any carbon tax advantage just offsets storage issues. The multi-fuel capability makes perfect sense for the future -it doesn't cost much and can save in many ways.

 

paste this into google and start reading

"lng powered ships"

There is a good chance when the Shell offshore liquidification vessel the Prelude starts to operate Australia will mandate all vessel operating there to be lng
It has been built to not only fill lng tankers but refuel vessels

 

started a new thread here

http://www.boatdesign.net/forums/pr...-frettner-rotor-project-50587.html#post690828

 

So if Power = force times speed, why is KW or HP a wrong way of expressing performance ?

Again - they have KW in the Polar diagram.


So, explain why you said my referencing Kilowatts or HP is wrong in the previous posts !!

 

As previously stated, and show in actual performance graphs, Rotors can approach the wind as close as 20 degrees.

Kites can only work when the wind is in the stern half of the ship





PS - the Power figures in HP and KW are in the table at the monorotor.com link, Rastapop.

 

So that would imply that kite surfers cannot go to windward.... yet they do.

a claim made by the same people who say kites don't work to windward...

Fig 1:2 of http://usir.salford.ac.uk/14811/1/360406.pdf shows Flettner rotor best L/D of about 2.
That means apparent wind needs to be at least 26 degrees just to get the force vector perpendicular to the keel.
Low L/D, a hull with little lateral resistance(lots of leeway and it's additional drag) plus the power needed to drive the rotor diverted from driving the main screws; suddenly Flettner's device looks to be the one that can't work higher than a beam reach.

To get the thrust up to a level of half the total rotor force you need apparent wind at 26 degrees for L/D + 30 degrees to rotate the vector forward to where the component along the keel is 50% of the total. Then if for example the ship speed is the same as the true wind speed you need another 45 degrees to account for apparent vs true wind direction. That's a total of 101 degrees.... And that is before putting the leeway, drag-from-leeway, and the effective drag resulting from diversion of the power to drive the rotor into the situation. There's no mystery in why rotors are not being used!

 

"to windward" is a matter of degree.

Kitesurfers are not Cargo ships, but even they cant get to windward well
"What is going upwind?
Going upwind is moving with an angle of 70° to a maximum 45° toward the direction from which the wind is blowing. - "

http://www.sbckiteboard.com/kiteboarding_101_display?news_id=324

If you look at the Polar diagrams supplied with the Kite study, the performance is closer to 80 degrees maximum for a cargo ship.

Which is what I am saying. Actual published results from Flettners boats achieved higher than 25 degrees, but even that is acceptable.

Remember that a Rotors Life coefficient is at right angles to the wind. The attached Polar diagram shows that your theory is incorrect. Actual performance figures show that the Rotor can be useful at very high angles to windward.

The power required is only about 50 hp for a large ship, which is hardly a problem for 1000 hp diesel engines typical on large cargo ships. In practice, its easier to use two small hp engines for each rotor rather than a power takeoff from the main engine.

I am sorry, I don't follow your logic here. I can only repeat that actual sailing performance figures are superior to standard sail standards.

 

Clearly, you don't. Nor do you seem to understand that the polars you are showing are not sailing performance polars. They are thrust component polars that completely ignore the side force and leeway aspects.

Further you claim that the polar proves that kites must have wind from aft of the beam to function. However, in this, you are misinterpreting the authors arbitrary breaking strength limit for the kites.

 

Feel free to explain more

So the polars are about breaking strain ?????

 

The straight lines in the polar represent the point where apparent wind is high enough to make the kite lift force exceed the author's arbitrary strength limits.

 

That is a side issue.

The main intent is to show the force in all wind directions obviously, as the Flettner rotor has no cable.

Once again, the polars show that wind from a direction more than ~80 degrees from dead ahead cannot be used by a kite.

 

Once again you are misinterpreting the polar. The author is not showing the kite going closer than 80 dregrees because he has arbitrarily decided the kite is not strong enough. The kite has better L/D and will go closer to the wind than the low L/D rotor.

 

I am curious why you say this, Fred? Do you refer specifically to petroleum cost, or to energy costs in general? Do you refer to cost or to price (sometimes not the same thing)?

Many reasons, the drive for efficiency will not be reversed so the world is slowly doing more with less ,, LED lights for example.

Dead dinasours as the source of oil is over as a theory , that the Earth makes oil from methane a few miles down is the current concept.

Waste as fuel , plastic or rubber tires to fuel oil or methane from a garbage dump is also here to stay.

Fracking , has just begun as a fuel source , so much of the world is un researched in terms of fuel.

The dream of Fusion power has remained a well funded dream for half a century , with nothing but paper to show for the cash.

Finally in much of the advanced world DEFLATION is slowly advancing. Much to the horror of govs deeply in debt money is not loosing value.

The working person will find his cash buys MORE (although his home value will not go up).

Fuel will cost less as a percentage of income, but pay raises will be a thing of the past..


Thorium used as a nuke fuel has almost none of the problems ( or possible bomb waste) as the Uranium power plants do.

Once it was thought that nuke power would be so cheap, there would be no reason to have a meter , that dream is back on the drawing board.

So a 50 gal drum with a bearing and slots cut in , or a recycled parachute may not be of much interest in the future.

 

Could you please refer me to the page and location of that information.