Anyone who has spent considerable time afloat with variable weather conditions will know that the trickiest part would be coming about or quartering islightly away from the oncoming wind. Should your hull present a large surface area, you'd be set back substantially. Cats make a good design defense against this problem, of course. But a big sided monohull would offer a stiff resistance.

Wow! Swinging boom hazard replaced by whirling blade hazard! Ouch!

This is an old concept. There were windmill-powered wagons in Britain in the 1700s, although more as toys than anything.

Sailboats can in fact sail very close to the wind sometimes, and with good sail management can actually go faster nearer into the wind than ahead of the wind.

I can however totally see where this would be useful in some instances. It might be perfect for double-ended ferry service, because you would not need to turn the boat around at each end, like you would with a sailboat ferry.

Perhaps a better design would be a vertical wind turbine (with very good anti-hand-chopping-off guards around it). That would distribute the mass and force along the mast length more evenly, like a traditional sailboat. This would eliminate the mast wobble caused by blades whirring in an off-balance arc. That would also allow a lighter mast.

You could never go directly into the wind, however you could zig-zag back and forth at 45 degree angles to the wind the same as if you were sailing.

Someone seems to hold a patent for vertical wind turbine boats they even make particular mention of cataramans.

http://patents1.ic.gc.ca/claims?patent_number=1272072&language=X

You get all the problems of a wind based ship. Namely, [i] you can't run it when there is no wind [/i]. You also have the added problem of mechanical parts to go wrong. As previous posters have said, it just takes a busy crew to go in the direction of the wind (not into it). I would also think that on rough waters this would be very top heavy and fall over, as the hull looks low and light, with, presumably, many metal, plastic, and other heavy components on the top.

I personaly like this one http://www.transatlantic21.org/ , powered the sun.

I had the same idea too, I guess ints not a big logical step.

Good to see someone put it into practice.

Fantastic!

Interesting,

As many have pointed out, winds do not always cooperate, so why not go the next step and integrate a generator into mechanism combining electric power with same mechanical wind mill power?

Sale boats need ballast, so a bank of batteries used as ballast would solve the extra load factor and to top it off, integrate solar into hull surface design and now you have something to boast about. A direct drive from windmill effect doesn't do it for me.

ITS-YOUR-NET.com

I don't see why this wouldn't work. The wind is moving but the water is stationary (unless you are in a river or tide current). The only resistance to overcome is the wind and hull (and limited minds). Even if the wind had a 10 to 1 ratio to boat speed the boat would still move against the wind.

Idea was in Popular Science 75 years ago.

I am a Naval Architect and can shed some light on this subject. This concept has been around for years, although this is probably the best use of it I have seen. When I was growing up, there was a converted tug boat that had a similar propulsion system and even that high drag hull could go directly into the wind. A light catamaran could probably do it rather quickly. Some misconceptions in the comments above which I can dispell: Catamarans do NOT need ballast. Their stability is derived from the flotation and separation of the hulls. This boat could certainly go directly into the wind, and would NOT need to tack back and forth like a traditional sail boat. The energy losses of converting to electricity and then back to mechanical power would significantly hurt the speed of such a vessel. Although generators and motors are becoming far more efficient, it is still hard to beat mechanical gearing. Where this boat would see it's biggest problems would actually be going downwind, where it would probably be far faster to jibe back and forth to get downwind. This would allow the boat to use apparent wind to go faster than if it just pointed dead downwind.

The survival rate of those CF blades in heavy storm probably would not be that great. Lots of odd angles of force would be applied to the blades. Further, you lose the blades, you lose your source of propulsion- just like a sailboat too, I suppose. I've just seen enough demasted boats in my day to think this would be a great idea... would be very neat on a moderate day, though.

This might be a good way to reduce emissions from big cargo ships. Wind power could supplement the diesel engine. Unlike sails, it would not require radical changes to the design of the hull, and with automatic controls it would not require any additional crew. It could create a problem with loading and unloading container ships though.

Ok, so this is probably just a clever photoshop image, but even if it isn't, it would be impossible for it to go directly into the wind.

Why? Well, it's because of something called efficency. The wind turbine isn't 100% efficient in converting the wind energy pressing against it into rotational energy. Now, if you were to gear the windmill to the propeller, the propeller isn't 100% efficient in converting rotational energy to forward motion.

Strictly speaking, since no machine/process/whatever can be 100% efficient (physics working against you there), it would be impossible for the (wind powered) boat to even tread water facing directly into the wind.

Not to say that this hasn't been tried; here's a website that talks about autogyro boats: http://uk.geocities.com/fnsnclr@btinternet.com/yachts/auto/hist4.htm

If you consider standard sailboat sails, they work like airplane wings poking straight up out of the water. They can tack into the wind because the sail generates forward lift along with downwind drag. High performance boats can tack at relatively small angles to the wind (45 degrees or so). When you "come about" or turn across the wind, you're pretty much coasting until you get to around 45 degrees from upwind in the other direction.

I'm not saying that this type of vessel could not work, I'm simply saying that it couldn't travel upwind without some additional power source. Anyhoo... I just thought I'd throw my $.02 in.

Cheers!

The last comment by David can not be more wrong. Clearly, he is not up to speed with what is going on in the boat research field.
The picture of the "windmill" boat is certainly no photoshopped image. This boat is the second wind-turbine boat made by Jim Wilkinson who is a member of the AYRS or Amateur Yacht Research Society. It works.
I myself am an experimenter who has made a successful windmill powered boat. As it happens, I have just uploaded a video of my models to youtube, check it out on: http://www.youtube.com/watch?v=GzNq3aEyP2w

I must disagree with David's logic. To examine the feasibility of the windmill boat sailing directly into the wind, I offer an analogy. Yesterday, I hoisted a 500 lb engine using a winch and my hands. As I pulled downward on the chain, the engine lifted off of the ground. I only weigh 200 lbs. According to David's logic, this is not possible because Since I have only the force gravity and my weight to work with, the 500 lb engine could not be lifted using a pulley since the engine outweighs me. But clearly, this happens every day. It's called a mechanical advantage.

With respect to the windmill boat, as long as the gear system leverages the wind, even with mechanical losses in the system, it can produce a resultant force many times greater than the force of the wind at the cost of speed. Since the resultant thrust vector is always a balance of forces acting on a center of gravity, the only forces that matter are propeller thrust, wind drag and hull drag. Drags can be minimized by better aero- and hydrodynamic engineering. This can drive efficiencies of the propeller up as well as the forces harnessed by the wind turbine.