Windmill or Wind Turbine- powered boats: how many are out there, and are they viable?

[Richard Atkin]

Windmaster, I agree that it is good to criticise each other's designs. I don't know a lot about boats and physics so I tend to just ask annoying little questions!
Rick taught me about the advantage of a 'tiny' little rudder. The rudder produces much more steering force than you would expect, because it is not surface piercing which means that ALL of the rudder is producing lift. Surface piercing rudders suck air which renders a large portion of the underwater surface useless. Looking down at Rick's rudder from above, you will notice that the foil shape is very fat,
This proves to be a better ratio between lift and drag.
I have the same sort of rudders on my catamaran design.

I will wait for Rick to respond about yaw issues with the wind turbine.

You can find indepth discussion and diagrams about this efficient type of rudder in my thread (Trying to design my own cat) and JCD's thread (Poll: Catamaran Evolution). Both threads are in the multihulls section.

[TeddyDiver]

Originally Posted by Windmaster

You are mounting it on the extreme stern of the boat I think this may lead to handling problems. In a beam wind.
It would be nice to hear the comments from any others who are interested. Whether they agree or disagree about my understanding of Rick's design which he has shown to us and therefore invites us to comment.

So far I've been only a listener here. So much that I really like the concept.
I think you got a point with the handling problem, but I reckon it's more an issue with keel/rudder placement.. There was for sale a stern drive sail/rudder unit a few decades ago. Placed like any sterndrive unit.

[Guest625101138]

Originally Posted by Richard Atkin

Fair enough, Rick (regarding the styling).

I can't see the point of making anything demountable, other than the wind turbine. If it's on a good submersable trailer, why would you want to pull the whole thing apart? Getting it in and out of the water could still be a one man job, using an electric winch? Or am I overlooking something?

Richard
It is 12m long. I want to stow it at home or in a boat storage shed. Something 12m long is just too big for this. I also think it might be overlength for tralering.

Rick W.

[Guest625101138]

Originally Posted by Windmaster

Rick

Having looked at your design, I have the following comments to make:
Positioning of the wind turbine:
You are mounting it on the extreme stern of the boat I think this may lead to handling problems. In a beam wind. Using two blades - which is what you intend - you are running the turbine a high-speed (8x windspeed?). The disc of a high-speed turbine presents an almost total obstruction to the wind (remember Lin Olen's comment that a fast-rotating windmill pulls better than a spinnaker downwind) - If you don't believe this you only have to think how an autogiro (gyrocopter) works.
So what it really amounts to is the equivalent of a sail the size of the swept area of your turbine mounted at the extreme end of the boat. With this running so far aft of the CLR in a beam wind you are going to get a considerable yawing force away from the wind at the stern, and you will have to use considerable rudder authority to counteract it and I notice the rudder shown on your drawing is absolutely tiny! You could get round this of course, by mounting another turbine at the bows. Or mounting the turbine on or near the CLR.
Going directly into the wind however the drag from your rear-mounted turbine will serve to keep the boat going head to wind - however you could have a problem when you want to turn away from the wind!
Maneouvrability: You seem to have designed the boat purely for high speed without any regard for handling - the turning circle would be very large indeed and there is a total lack of "rocker" on the hull which is the feature that allows a boat to "come about" more readily. You could certainly be embarrased when you attempt to turn in a harbour or narrow river.

I think the purpose of these forums is to share ideas and constructive criticism and not to just complement each other.

It would be nice to hear the comments from any others who are interested. Whether they agree or disagree about my understanding of Rick's design which he has shown to us and therefore invites us to comment.

Windmaster

If you go back to the original postings under Coastal Cruiser you will see it did get some critique. Not all comments were positive and I have had some unflattering responses from other sites where I have shown the concept. All thoughts are gladly accepted and taken into consideration.

I am a guy on the experienced side of 55yo who races sailing boats and kayaks in pedal boats. You want to hear the flack I get from home!

The steering moment from the placement of the turbine is a concern. The rudder will need to be oversize to cope with this. Unlike the long keel for the battery, the rudder will be a very efficient foil. It will have a maximum L/D ratio around 25. So if side force is at the controlled maximum of 250N then rudder drag contribution to compensate will be less than 10N. Will cost an extra 35W at 7kts. So it is not a problem from efficiency perspective. It may be a problem in varying wind where constant course directions may be required as the rudder loads and unloads. But a long slender hull with little rocker will track well so I am hopeful it is not annoying. I certainly intend to have an autopilot. Overall I think the autopilot will find it easier than say a yacht running downwind in light wind but with a decent swell. I found the only way to use the autopilot in these conditions was to run goose winged with the genoa poled out and the main boom tied off so it could not accidently jibe. Solar-Wind boat should not suffer this problem.

I did consider mounting a balancing turbine on the bow of the boat. The two would be a bit smaller than just one. However this would interfere with deck space and I intend to beach the boat bow first. I also considered mounting above the cabin but it would be hard to mount and demount from that position and also increases overturning moment because it would be around 1m higher.

Rick W.


My greatest concern was someone getting whacked with the blades as they really do belt around. My blades will need to be strionger than domestic units as I expect them to survive gale winds. The first ones will be alumiium flatbar with folded sheet for fairing. They would cause a nasty head wound if struck at high speed so for safety reasons they ned to guarded off.

I do not intend to race the boat around buoys. My aim is coastal cruising so the lack of rocker should not be a constrant. I do not have to worry about tacking as it will go directly to windward.

Rick

[Guest625101138]

I should add that the boat is aimed at what I perceive my needs to be in retirement. It is not a practical boat for taking a large family on a boating holiday.

The interior is not roomy for a 12m boat. I increased the beam to at least get it useful.

The numbers I have done on comfort indicate its roll may be too sharp for good comfort but there are lmany things at play here and very complex to analyse. I may end up making a model but I already have V12 pedal boat that has a similar hullform. Apart from the fact that I know it will capsize if I get it beyond 50 degrees it handles beam sea well. As you would expect it tends to ride up and down without rolling. I can get it to roll significantly by turning fast. It leans into the turn, which is a comforting feeling but I could probably capsize it inwards if I gave full rudder.

For its weight it will be quite expensive.

Hopefully it will give me something to muck about in in my retirement while keeping Brian happy with oil conservation.

Rick

[Richard Atkin]

You can always move things around a bit after it's built. I have no doubt it will give you a lot of pleasure when everything is fine-tuned, and you are out on the ocean with a hot/cool drink and a comfy seat.

All the best

[Lin Olen]

Hello Good People! Most comments are constructive and to the point. I sailed on Oriana's last trip out of Brisbane hoping to promote a trial of a Rotary Sail. Met with the Captain and an Engineer but found them hard to convince. They set me a problem which I solved for them but I was sorry to see this beautiful ship retire with a flow disturbing mustache high upon it's bow. A series of aircraft props as Rotary Sails mounted above the boat deck could power this mighty ship at speed 10 degrees off the wind. Cheers, Lin

[RHP]

I aint going to trawl thru 11 pages of posts just to see if this has been posted, but if it hasnt, it will be of interest to turbine fans.

http://www.tennantdesign.co.nz/index...age=revolution

Enjoy
Richard

[Richard Atkin]

Very interesting RHP. I go back to my previous statement....big turbines like that must feel quite intimidating and not very relaxing. Woosh woosh woosh. Noisy too. In my opinion, a huge thing like that should be for industrial/commercial purposes. Not for holidaying.
I can imagine people buying the boat, and then trying to sell it a couple of years later.

[RHP]

Talking as an innocent with zero experience of boat based turbines, not only would I fear the visual movement would make me seasick but I'd find myself constantly ducking to avoid imaginary incoming Stuka dive bombers.

All in all not my idea of a quiet day out with the kids.

[Guest625101138]

Originally Posted by RHP

Talking as an innocent with zero experience of boat based turbines, not only would I fear the visual movement would make me seasick but I'd find myself constantly ducking to avoid imaginary incoming Stuka dive bombers.

All in all not my idea of a quiet day out with the kids.

Or you could have a much smaller turbine charging battery ballast through the week and go for a totally relaxing stress free ride in a silent electric boat on the day out with the kids.

Lock the rotor before you set off and not be concerned whether the wind blows too much or too little. No need to start a smelly diesel. No need to worry about getting fuel - ever. Heck you could even add a couple of solar panels to top things up if the wind doesn't blow. No flapping sails. No swinging booms. No need to tack up a windward course.

Rick W.

[Windmaster]

This should be happening already. I can't understand why not.
After all, small power electric power producing wind turbines are easily obtainable. I can imagine a few of them mounted on the roof of a boat to charge up the batteries for the weekend jaunt.
Yet you never see this, all you see are solitary ones mounted alone on a few cruising yachts, just to keep the nav and lights going.

[RHP]

At what stage does yachting stop being yachting? To a large extent we are satisfying mental and physical needs when we retreat to our boats at the weekend for a a well deserved break, a reunion with nature and traditional seafaring ways. Personally a wind turbine sat atop the cabin does little to sooth away the midweek blues, flat batteries I can live with, sharing a 30 footer with a windfarm seems to defeat the objective.

[Richard Miller]

Originally Posted by Rick Willoughby

Or you could have a much smaller turbine charging battery ballast through the week and go for a totally relaxing stress free ride in a silent electric boat on the day out with the kids.

Lock the rotor before you set off and not be concerned whether the wind blows too much or too little. No need to start a smelly diesel. No need to worry about getting fuel - ever. Heck you could even add a couple of solar panels to top things up if the wind doesn't blow. No flapping sails. No swinging booms. No need to tack up a windward course.

Rick W.

Hi Rick;
Would´nt electric motors have a whinning/grinding sound to them? I´ve been following your additions to the forum and you seem to know what your talking about. You and I have a common friend: Pete.
Would like to hear from you Rick. I have built 2 WT models that worked well, and the local university has taken my full sized, 2 passenger model on as a project and hopefully will build it form my drawings with Pete´s advice.
Richard Miller
richardmiller592@hotmail.com

[Guest625101138]

Originally Posted by Richard Miller

Hi Rick;
Would´nt electric motors have a whinning/grinding sound to them? I´ve been following your additions to the forum and you seem to know what your talking about. You and I have a common friend: Pete.
Would like to hear from you Rick. I have built 2 WT models that worked well, and the local university has taken my full sized, 2 passenger model on as a project and hopefully will build it form my drawings with Pete´s advice.
Richard Miller
richardmiller592@hotmail.com

Richard
Yes they do and the noise gets magnified if motor is directly mounted to an aluminium hull. Listen to the video on this page:
http://boatdesign.net/forums/showthread.php?t=20445

I intend to enclose the motor on my solar-wind boat and direct some cooling air into the chamber.

Are you using a VAAT or HAAT type.

I have a reasonable theoretical model of a HAAT but nothing for a VAAT yet. The straight blades make the latter less complicated aerodynamically but the dynamic force ballance for pitch control will be quite complex. I have not started on this exercise yet.

If you want to play around with the theory and have some computing skill and maths ability I can assist.

I would love to see a video of your turbines. Even some photos. Did you get any power measurement?

Rick W.