Would You Consider Sailing, But Without Sails?

It is, and is a good read, especialy if you follow on to the next chapters.

 

I'll keep pondering ideas.

I think it may be the familiar, that's keeping it going.

 

It was the ease that was the idea.

 

So you started the thread to suggest windmill powered boats because they are worse than sail? No You implied it is better. It would have to be to justify the cost and risk.

Moving parts -the 3 blades must rotate in the hub to adjust pitch, there are dozens of moving parts to accomplish this. The hub rotates relative to the nacelle to transmit power. Next is a gear box with dozens of moving parts then the generator with one more. The nacelle needs to rotate relative to the boat to actively point into the wind -another motor and gears. There is also a brake system for safety -more parts. So that's around 100 parts and they are at least 30ft above deck. The electric boat below might be equivalent to an electric aux sailboat but with far more batteries.

The windmill tips must reach a high velocity to generate enough power. They are dangerous in a large volume over the boat.

You suggested the the windmill boat would offer advantages to sailors with disabilities -you put them on the boat hypothetically which I responded to. Nobody is implying you are forcing anyone -just floating an idea asking for response. My response; bad idea, this is why...

 

Horses for courses . To be honest with you the power from wind is at best marginal and at worst has to be the most expensive way ever invented to move form A to B compared to big diesel inboard . I once saw in about the mid eighties a tomorrows world emission where a large trimaran had a windmill on it and it would head directly into the wind at some leisurely speed something like 3 to 5 knots .Don't ask how you can feather the blades in force 10 gale . The problem with wind power as every wind mill type electric wind generator s will tell you is that the power quadruples when the wind speed doubles . If you happen to know some basic maths and use computer projection programs it possible to estimate the power from sails or wind turbines or other wind driven equipment like wings from planes or kites for kite sailors .
Very quickly from these programs it becomes clear as day that the power from the wind is not a lot compared to the size of boat and size of sails until there is wind blowing force 6 or more .This 6kwatts of power you refer to is about equal to a small single cylinder ~10BHP diesel engine .
The big bug in the works is the downwind sailing .Where the windmill might perform interesting well in 16 MPH wind going directly against the wind as soon as you go downwind the same wind will be less . Large two or three propeller blades dont have much surface area and down wind sailing speeds are made with large sails like Spinakares and Genoa's to catch the wind . To make more propellers to make the extra sail area would often add a lot weight .Also carbon fibre plastic is very heavy compared to sail cloths like Kevalr. Carbon fiber like all plastics is typically 2.5 times more weight than the same thickness in marine ply .So just to get the weight similar to marine ply it has to be made 2.5 times thinner .However the rigidity of carbon fiber when it gets too thin becomes a problem so then you need to add foam and make a sand witch to keep it rigid enough and that all makes it relatively heavy OK strong but heavy.Compare that to sail of Kevlar .The mast is probably light weight aluminum with stainless steel wires and then a light weight Kevlar sail .Kevlar is thin strong same in tension as sheet of stainless steel but a lot lighter then stainless steel .However Kevlar is not rigid which is useful when you want to fold it away. However the lack of rigidity of Kevlar comes with its own problems so it requires battens to keep its form shape to be useful. The kevlar materiel has no real ability to resist chafing and can have holes worn into it in minutes from lose ropes .
The real bug of all boats with sails is they are close to the water where the wind has less power .One 60 foot racing boat I know will often do 5 knots in calms as it catches winds higher up and also probably the deck heats up to send warm air upwards to keep it going .sadly smaller boats cant reach to the skys to get the wind unless they are Kites sailors on their boards .Now what many people dont see about kite sailors is they often make their sails do figure 8s in the sky instead to just let the kite pull them down wind . the reason for this is not only do they get more power because the sail is high up some 100 feet in the sky but the diving part from the figure 8 will double the wind speed and quadruple the power they get. . However trying to scale that up would be tricky and dangerous as large sail could easily pull your arms out of your sockets if grip was strong enough . However nothing to stop you getting some small 25foot open deck light weight cameraman type boat with no mast or possibly wide light weight dory with lee boards us the engine to get out to sea .then put a few people on the decks with wind kites to pull it along .It might make the boat move along a bit clippy on a reach if there a few sails at work .The boat would have to be light as heavy keel boat wont want to know. It wont work so well if the wind gets up or if the wind is less than 10mph .For handicapped it will probably only suit those whose still have strong arms . Maneuverability will be very bad so requires lots of sea room .Also as the sailors can not relive the power as kite sailors do with going downwind and hopping into the sky there will need to be deck fitting to take the loads and the person steering the sail will be really only pulling on the cords to steer it .From that it might become clearer how to make larger kite sails that can be controlled from the deck like normal sail can be and if it cant be scaled up well it would be a bit of fun to try out the idea .
You really need to think this through research all the stuff that ever done and look the aircraft world like gliders and par gliders to get to know the forces and the real lack of BHP from wind before trying to make heavy solution that barly works .just my 2 cents worth
David forever paddling upwind in a rubber duck

 

That was far more than 2 cents worth, and very good.

 

Pure sailboats can be made very user friendly, if one goes to enough trouble to make them so.

First, sails can be made easy to furl and reef.

Second, booms, can be raised high enough, moved far enough aft, or eliminated completely, to remove the hazard they present.

Third, when coupled with a modest engine, and reasonably large fuel tanks, the size of the sail plan can be reduced to make it more easily managed, but still quite effective in decent sailing weather.

Just about all these reforms tend to reduce all up maximum performance, so are not particularly popular with the sailing press, which seems to be obsessed with youth, power, and speed.

All of these are far less expensive to build and maintain than a huge wind turbine, which can experience severe loads as the boat rolls and pitches.

 

Only three moving parts?

You are dreaming.

This has been discussed a number of times and it always falls apart when it gets looked at. The engineering simply does not work.

Sure, you can get something mounted on a boat and get the boat to sort of move, sometimes, at some speed, depending on various bugger factors, but compared to the cost & complexity of doing the same thing with sails, it's pointless. There is no gain at all in return for a great deal of complexity.

Now before you start arguing, please name the 3 moving parts that you claim are all that's needed and we can discuss their sufficiency (or not).

PDW

 

Good comments all.

Diesel engines: lots of data to suggest its very easy and cost efficient. Just notice that virtually 100% of shipping uses diesel instead of sail.

And wind mills certainly do generate lots of power, large ones generate far more than a sailboat uses to move around and keep the ice cream solid.

However, let me point out that sailing is simply fun. Pushing throttles, or watching current meters... Maybe not so much.

A 747 is an amazing way to get around. Stay in hotels where the cost is efficiently spread amongst many. Use electric utility companies, where energy csts an order of magnitude less than you can generate it on your own (mega economy of mega scale).

But to me, sailing is fun! 747s, hotels, and utility bills just don't do it for me anymore.

 

About diesel ships -by international treaty they pay NO TAX ON FUEL and I have read numbers as high as 20% of greenhouse gases are from international shipping. If (when) there is a worldwide carbon tax sails will dominate the seas again.

 

nah... with global tax on carbon, you will simply see higher shipping costs. the costs of the fuel for shipping are still dirt cheap. The reason the emmissions are so high is they burn Bunker Crude..... stuff that is so gloppy it has to be heated with high temp steam just to get liquid enough to run into the boiler

 

You have misconceptions about the cost add. It's not

(small percentage tax) X cheap bunker price = 120% of old price

it's (BIG CARBON TAX) + cheap bunker price = 300% to 500% of old price

30 cent/gal bunker muck contains more carbon than $3/gal gasoline so it would owe more than the $1/gal tax. So for a container ship who's biggest cost is $50K/day fuel, sails are the sane alternative to $200k/day fuel cost.

 

when you are carrying 18,000 TEUs at a price of $5k/TEU, you can absorb a lot of cost.

 

I must be doing something right, I've concluded, after much research that this thread has sent me on.

I may have to change my Sail's Pitch though.

Thank you, all.

 

interesting thread, I got a good laugh out of the Gougeon Flettner rotor experiment, they considered it a success powering the rotors with 2 x 10 hp electric motors drawing from a battery bank that needs recharging when 1 x 20hp diesel would also have achieved the 6 knots they achieved easily with good range.
Someone mentioned the boats built in New Zealand that were windmill powered,as I recall one was an old Yachting world diamond widened aft for stability and the windmill powered a large propeller mechanically rather than electrically. I believe that a large Malcolm Tennant designed catamaran was built with windmill power, I don't know how that turned out. I would think that a cat would be an ideal platform for both the windmill and the disabled boater, if i remember right there were problems with the Diamond when it would get hit by a gust and heel over it could dig a tip into the water with disasterous results. Im not going to try to dissuade you from your idea but rather make a few suggestions
1/ use a catamaran hull form to provide a stable platform that would be most suitable for disabled persons to move around on.
2/ rather than a windmill for the generator research using a 3 bladed vertical rotor, i saw a rather large one in New Zealand 40 years ago that was feeding in to the national grid and it struck me then that it would have advantages being omnidirectional so always facing into the wind and by rotating on a vertical shaft would be somewhat safer, it could also be easily stayed keeping weight down.
3/ Use an appropriate diesel generator as a back up.

Steve.