Winddriven propellers

jimi

jimi

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As there have been far too many frivolous posts here I've decided to take the bit between the teeth and start a serious one myself. So I do'nt want any nonsense from you lot on what is a genuine scientific enquiry.

Right .. deep breath ..

Would a wind driven propeller work? .. ie a big wind driven vane to a propeller in the water and use it for propulsion? Would save a lot of diesel and keep the environment a lot cleaner. Save all this nonsence about sail trim as well

<hr width=100% size=1>.. when's that again, but ..
 
do you mean the twins 36 that was in Plymouth a couple of seasons ago?

That had 1.5 metre diameter prop to a large turbine on the deck. Apparently they should have used the 40 ft hull cos the 36 ft hull squatted due to the forces on the turbine when going to windward. I think the boat is now in Jersey?

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Re: Flettner Rotor Ship

s'pose on starboard tack with wind thing rotating clockwise (i'm assuming a jock cocteau type turbine that rotates on the vertical axis). with enuff wind the frictional losses etc on the boat will start to rotate it clockwise which will require port helm - so the boat will tend to round up to windward. if turbine rotates anti-clockwise the helm requires to be put to port so the bluidy thing will b*gger orf into the gloaming .. oh and it can't work on a crummy little keel eg awb, can it?

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O for originality

yawn, sigh...
where've you been then?
Proof, if proof were needed of what happens when cousins marry.
My new years revolution fer wee jamesie is that during 2004 he has one original thought.

<hr width=100% size=1>regards
Claymore
/forums/images/icons/smile.gif
 
There used to be a Catalac in Bradwell Marina which used a large wind turbine (8 m diameter?) driving a water prop.

Ross Garrett's book "The Symmetry of Sailing" goes into the theory of such a craft. He gives results and a photo taken of a turbine boat using an 8 m diameter three-bladed variable pitch airscrew mounted on a 9.4 m monohull. He reckoned that in 14.5 knots of true wind the boat logged about 7 knots, independent of wind direction.

He also reckoned that such a craft could, theoretically, go faster than the wind downwind. In this mode the water prop would be extracting energy from the water and driving the airscrew to produce thrust. In fact, he used this case as one justification for the title of his book.

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I had asked my self this question some time ago. Remember seeing an article about various designs to test the concept and it worked! If I remember correctly there is an example at Irvine Maritime Museum that uses an adapted helicoter tail rotor through a gearbox to turn an underwater propeller. Could sail straight into the wind. Just phoned the museum and they do have such a beast.

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<He also reckoned that such a craft could, theoretically, go faster than the wind downwind. In this mode the water prop would be extracting energy from the water and driving the airscrew to produce thrust.>

He must have had a bit too much to drink when he wrote that. Beacause if its true, he's invented a perpetual motion machine, and all the worlds energy problems are solved!

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Propellor in the air

Jim - just got back to see this interesting post. I presume that you are wanting to take advantage of the capsize mode for a Beneteau. You will need to modify your propellor for something bigger, but as you have seen from the other pists, the whole idea is quite feasable. There may be one or two operation problems like - how do you keep the Gin bottle in place whilst in wind propeller mode. - but nothing a great scots engineer should not be able to deal with.

Crappy Histmas to you all

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Almost

What you did was gave a page address rather than image address. The image is embedded in the page and needs to be extracted. On a Mac you do that by clicking on the image and holding the mouse down which gives an option to display the image in a new page. I think, on a peecee it is achieved with a 'right-button' click. It is this 'new page' address which you need to include, thus:

windmill_boatPA300x516.jpg


<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>
 
Wouldn\'t that sort of thing...

...be much better employed driving a generator, which would power an electric motor driving a prop?

Much better, surely, than having gears, pinions and shafts cluttering up the downstairs?

Can see why it needs to be on a cat. It could get to be a very interesting rig if the boat heeled much.

"Yes sir, i know you've got your yachtmasters ticket but it's your pilot's licence I want to see."

<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>
 
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