Is this sailing?

[handmer]

Originally Posted by boat_alexandra

This obviously is very poor performance compared to sails in all angles except upwind.

The physics of a wind turbine powered craft mean the best performance is actually both upwind or downwind, and the wind speed can be exceeded.

I presume not this boat in particular though.

I am not sure if anyone has built a boat efficient enough travel faster than wind speed directly up or downwind, but the same concept on wind turbine powered cars has been demonstrated.

https://en.wikipedia.org/wiki/Blackbird_(land_yacht)

[Pete7]

Originally Posted by StuM

IMNSHO:
It's definitely a power-driven vessel. The fact that the power is derived from a wind turbine is irrelevant. It's only a sailboat if the force of the wind is directly transferred to the vessel's motion through the sails (and their rigging).

Strange, I thought windmill blades are called sails?

Pete

[Pete7]

Originally Posted by Dave_S

Ha ha. :-)

But it still won't take wind head on and make ground.

Au contraire:

https://www.treehugger.com/renewable...-the-wind.html

"Someone was thinking outside of the box on this one. The 36 foot catamaran, Revelation II, is powered by 3 20-foot long carbon fiber propellers on a 30 foot rotating mast. The windmill transmits power to a 6 blade propeller underwater, with the net result that the boat can make way even directly into the wind".

[StuM]

Originally Posted by Pete7

Strange, I thought windmill blades are called sails?

Pete

Again IMNSHO:

Even if you call the blades "sails", the force generated is not directly pushing the boat. It uses machinery* to drive the boat. (so COLREGs 3 (b) applies )

*Machine:
OED: An apparatus using mechanical power and having several parts, each with a definite function and together performing a particular task.

[danielamartindm]

I think I moored next to this guy one windy night in Block Island.

[Pete7]

Originally Posted by StuM

Again IMNSHO:

the force generated is not directly pushing the boat. .[/I]

Oh I think it is, in the photo in post No 1, there must be a sideways force acting on the above deck propeller and therefore the hull, it just isn't in direction the yacht is pointing.

[Dave_S]

Originally Posted by 44'cruisingcat

I read about this boat years ago. Apparently dead upwind was it's best point of sail.

Originally Posted by Pete7

Au contraire:

https://www.treehugger.com/renewable...-the-wind.html

"Someone was thinking outside of the box on this one. The 36 foot catamaran, Revelation II, is powered by 3 20-foot long carbon fiber propellers on a 30 foot rotating mast. The windmill transmits power to a 6 blade propeller underwater, with the net result that the boat can make way even directly into the wind".

This must have been written on the first of April ???

No, it's a scam, if the wind generator is attached to the boat any energy it can create is outweighed by the drag created by generating that energy. Then running that net loss through a mechanical or electric system to produce some form of propulsion to overcome that drag is not possible.

[Pete7]

Didn't they say the same thing about sailing down wind faster than the true wind speed, only for someone to build a land yacht and then do it?

Pete

[John_Trusty]

I always wondered about the efficiency of Cousteau's turbosail wind ship Alcyone, built in 1985. The wind supplemented diesel engines on the research vessel. There was not a wave of adoption of this technology, so I guess it was more of a gimmick than an efficient use of wind power to save fuel.
https://www.cousteau.org/english/more-vessels.php

[clockwork orange]

There must be large mechanical losses in the 2 large bevel gears.

[fahtcha]

How long is the cable between the wind generator and the boat?

[clockwork orange]

Originally Posted by John_Trusty

I always wondered about the efficiency of Cousteau's turbosail wind ship Alcyone, built in 1985. The wind supplemented diesel engines on the research vessel. There was not a wave of adoption of this technology, so I guess it was more of a gimmick than an efficient use of wind power to save fuel.
https://www.cousteau.org/english/more-vessels.php

This was not original work either, it was I believe a Flettner rotor powered vessel. My understanding (which could be very wrong) of the Flettner rotor is that a low powered engine turned the rotor rather than powering the underwater prop. I have no idea of how this contributes to forward motion. Its been a long time since I read about the Flettner rotor.

Steve.

[sailingunity]

Thanks for the video, though it looks like they are docking with a diesel engine from the water exhaust coming out the back?

No one over 6'5" allowed on board for insurance reasons

[Mariano]

I wonder how they handle it during a storm......

[Shrew]

https://en.wikipedia.org/wiki/Sail

According to the definition of sail, it is what is capturing the wind, it goes on to discuss 'using the power to propel a vessel'. Like a motorboat is 'motoring'. At best this would be 'turbining'.

This is only capturing the wind to convert it to stored energy, which is then used to power an electric motor, which then propels the vessel. In this case it is the electric motor that is propelling the vessel, not the wind or the turbine.