Has anyone actually seen this moving?

[RIN]

Saw this in Elizabeth Marina at Guernsey last week in QEII Marina. There was a write up nearby saying it was designed for wind speeds of 15 knots.

Have any Guernsey or other forumites seen it moving? The energy stored up in the propeller when under way must be frightening, and the gyroscopic effect of the prop must cause some interesting problems if the boat heels to the wind.

 

[boatbuilder]

It was built here in Millbrook, and it does indeed work. look at the multihull centre site.

 

[Major Catastrophe]

The Multihull Centre website is useless, except for a couple of pictures, which add nothing to the original post.

I did a bit of googling and discovered that the windmill does not drive the boat, but actually drives a conventional propeller, so I now understand why it was posted in the MOBO forum.

 

[Bandit]

The boat indeed works, the "AIR Propeller" which swivels and drives a fixed direction propeller between the hulls.

The boat also has a traditional engine in each hull for when there is no wind.

It is a wierd thing to see it sailing into the wind.

 

[Auntie Helen]

Quote from a random website

"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. Right now, you are either astonished, thinking "Why didn't we think of that before?", or your head is spinning with reasons why these boats are not currently plying the seas in great numbers. For instance, how well could such a thing possibly go into the wind if wind and water drag are offset by the forward propulsion generated? Or "who photo-shopped that windmill onto that catamaran?", for the real cynics. But it seems like there is evidence that the wind turbine concept really functions, and even some rather grainy video proof [their link went to a tiny wind-powered dinghy, not the cat]. If you want to evaluate some examples of the math for the proposition yourself (or just learn how a great forum can break down when we don't treat each other with respect), see the comments at Sailing against the wind. If you are leaning towards the photo-fixing theory, check out the Revelation II from another viewpoint at the Multihull Centre."

 

[Deleted User YDKXO]

Mmm, so I suppose that the more the wind blows, the faster it goes, in which case, does it do 50knots in a hurricane? Or is there some kind of control mechanism for limiting the speed?
Why is this a multihull concept? Can it not be used on a monohull?

 

[Nautorius]

Mike,

Given the weight of the rig I think a monohull would fall over a lot! Interesting option...but just plane barking to me!

Cheers

paul /forums/images/graemlins/smile.gif

 

[Deleted User YDKXO]

[ QUOTE ]
Given the weight of the rig I think a monohull would fall over a lot

[/ QUOTE ]

Why? A sail 'pushes' a yacht over but there's a keel to counterbalance it. Surely it would be the same with this thing?
I think the real reason is that the inventor already owned a cat and woke up one morning thinking what a good idea it would be to nail a propellor to it's roof. Praps the original idea was just to build one of those wind generator things you see on yots and he got his maths wrong?

 

[Nautorius]

True Mike,

But you can spill the wind from a sail, and because of the rig design the majority of force is exerted on the greater sail area which is at the bottom of the sail. With that thing a ton of weight is at the top with the rotars. Also if you get knocked down with a sail, it gets wet and then you carry on sailing. If you got knocked down with that it would get lots of sea water in it...would it still work? You would also need a huge keel to counter weight her!

Cheers

paul /forums/images/graemlins/smile.gif

 

[omega2]

There used to one of those if not that one in Bradwell Marina Essex a few years back, and yes I saw that one moving once not very quickly mind. The fan drives a gearbox that drives a propellor but it does not actually plane!!

 

[Deleted User YDKXO]

But I guess you can rotate the prop off the wind too otherwise it could over power the boat and if the prop mechanism does'nt like seawater, then it should'nt be on a boat. We don't know how much the prop mechanism weighs (it could be made of lighweight materials) so the keel weight could be minimised and, anyway, I guess the prop weight directly affects the boat's performance so it must be designed light
Leaving all this aside, it looks really naff so I would'nt buy it for that reason alone /forums/images/graemlins/smile.gif

 

[RIN]

I still think the real problem would be the energy stored up in the rotating blades and how it would get dissapated in an accident.

Also surely any gust of wind that made the boat heel would cause a force downwards (or upwards) at the bows from the gyroscope effect which would make it difficult to use.

 

[Wiggo]

Jeez, look at the head injuries the WAFIs already get just from the booms. Just think what they could do to themselves with one of those...

 

[JKay]

Seaside rescue?

/forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif

Cheers Joe

 

[Grajan]

There was a mono hull that was in the Boatyard at Tighnabruich a number of years ago that had a similar propulsion unit looks kinda scary to me

 

[RogerRat]

[ QUOTE ]
the more the wind blows, the faster it goes, in which case, does it do 50knots in a hurricane? Or is there some kind of control mechanism for limiting the speed?

[/ QUOTE ]

I think you'll find that it has a variable pitch windmill props, looking at the centres. If the wind was too strong, it could be feathered to reduce rotary speed. The rotating mast will mean that you could capture apparent wind when under way too.

The cat seems the best option to me as this gives a much more stable platform. I doubt if it's direct drive to the water props (even through a gearbox) though, more likely a large electric motor driven by windy mill turbine which is why it needs force 4 to operate.

The weight of the blades shouldn't be too heavy in carbon fibre either, while the mast is no longer than that on a 30' sailing cat and this ones 36'.

I know it looks a bit iffy but you have to give the inventor full marks for innovation.

What would you think if it could be developed to give 20 knots in a force 2 with a 3' windmill eh? /forums/images/graemlins/cool.gif

 

[PeteCooper]

I think that one is now in the museum in Irvine.

 

[PatrickB02]

To answer the original poster's question, yes, I have actually seen it moving.

I was out for a sail on Staurday afternoon, and saw it sailing down past St Martin's Point, albeit only from a distance. I have also seen it out once or twice previously, but again only from a distance, so I can't really comment on its sailing performance or whether it really can sail into wind.

 

[itsonlymoney]

If it was a different time of the year I would swear that bthis was an April fool. That thing has got to be a wind up /forums/images/graemlins/grin.gif