RedM Posted April 20, 2008 Share Posted April 20, 2008 Have you seen this? I'm gobsmacked. I'd love to have a go on it. http://www.hydroptere.com/_en/ I've no idea how hydrofoils work but to lift the whole hull out of the water so that it's almost flying is amazing. jCuP-XHefTo Link to comment Share on other sites More sharing options...
Wez Posted April 20, 2008 Share Posted April 20, 2008 Wow Link to comment Share on other sites More sharing options...
Guigsy Posted April 20, 2008 Share Posted April 20, 2008 Thats how hydrofoils work. Like an underwater wing to lift the hull out of the water so there is less resistance and its faster/more efficiant i guess. Very cool. More info - http://en.wikipedia.org/wiki/Hydrofoil http://www.boeing.com/history/boeing/images/hydrofoil_n.jpg Link to comment Share on other sites More sharing options...
Ewen Posted April 20, 2008 Share Posted April 20, 2008 Im not really into rag and stick boats, but that one is amazing:) Besides, it wont be too long before all motor yachts will be powered by sail;) The speed of a boat is basically governed by weight, power and drag. Weight can be minimised using hi-tech materials etc etc, and power can be increased with larger engines / more sail area. But even a lightweight, high powered boat still has to overcome drag. Drag comes in the forms of wind resistance (usually ignored) and friction between the hull and water. In the case of a fast power boat, drag can be dramatically reduced by using a planing hull form....this hull shape allows the hull to ride up on top of the water at speed, rather than plough through it. Once planing, the surface area of hull in contact with the water is vastly less than when the boat is static, or at slow speed. The drag (resistance) is greatly reduced, and the boat can go faster with a given power. In the case of a single hulled sailboat, the same principals would cause problems as a large sail area and small amount of hull in the water would be unstable...if keel weight is increased as sail area is increased, the overal weight / design would preclude a planing hull design anyway. Twin-hulled or tripple-hulled sailing boats provide a far more stable platform for maximum sail area / power, and allow the designers to come up with ways of making the hull rise up out of the water thus reducing drag. A Hydrofoil is basically a wing, and works in the same way...at speed, the aerofoil section foils will make the boat rise up out of the water, untill no hull just the foils and keel are in the water...the weight and power remain the same, but the drag (total boat surface area in contact with the water) is considerably reduced and it goes faster. Link to comment Share on other sites More sharing options...
Pete Posted April 20, 2008 Share Posted April 20, 2008 Link to comment Share on other sites More sharing options...
RedM Posted April 20, 2008 Author Share Posted April 20, 2008 Besides, it wont be too long before all motor yachts will be powered by sail;) I'm intrigued. Do go on. Link to comment Share on other sites More sharing options...
Pete Posted April 20, 2008 Share Posted April 20, 2008 I'm intrigued. Do go on. Fuel prices perhaps? Link to comment Share on other sites More sharing options...
RedM Posted April 20, 2008 Author Share Posted April 20, 2008 Fuel prices perhaps? Probably. I was hoping the Ewen was hinting at some 'sail' based engine or something. Link to comment Share on other sites More sharing options...
dangerous brain Posted April 20, 2008 Share Posted April 20, 2008 Nah just the fact that technology is advancing so fast that sails will be reliable and advanced enough to make engines unrequired. Link to comment Share on other sites More sharing options...
Ewen Posted April 20, 2008 Share Posted April 20, 2008 I'm intrigued. Do go on. Fuel prices perhaps? My comment was slightly tongue in cheek, but the basic issue is indeed fuel. Fuel consumption / emissions is going to be a major factor in the design / marketing / legislation of marine pleasure craft in the near future. The same basic concerns have already started to affect how these things are built, the oil-based materials and styrene emissions for example. It takes a special kind of person to remain cold to the fact that his 'pleasure' yacht uses 50 tonnes of diesel to travel 1000 miles...and it takes a fairly average person to question wether that 1000 miles could have been travelled cost / pollution free. Wind power is already making its mark in the super yacht / cruise ship market, and several wind power ideas are being tried by commercial ship owners / designers. Maybe bio-fuel will answer the questions in the short term, but long term, sail power will play a larger part IMO. http://www.kiteship.com/ http://www.skysails.info/index.php?L=1 Link to comment Share on other sites More sharing options...
Pete Posted April 20, 2008 Share Posted April 20, 2008 Nah just the fact that technology is advancing so fast that sails will be reliable and advanced enough to make engines unrequired. I think that happened around 17th century? Link to comment Share on other sites More sharing options...
RedM Posted April 20, 2008 Author Share Posted April 20, 2008 What about solar powered electric engines? Might be useful for the Sunseekers. Link to comment Share on other sites More sharing options...
Alex Posted April 20, 2008 Share Posted April 20, 2008 Ewen isn't there a ship that has 3 metal wing sails out there? Big-ass cargo ship or something...probably Japanese... Link to comment Share on other sites More sharing options...
Pete Posted April 20, 2008 Share Posted April 20, 2008 What about solar powered electric engines? Might be useful for the Sunseekers. Waaaaay too inefficient. The power requirements to drive are boat are quite high. It'd be like trying to build a Supra with the same power purely through sunlight. There are advancements in solar panel effeciency all the time. These guys have hit 40% effeciency now which is quite amazing. At what cost though I dare not think. Link to comment Share on other sites More sharing options...
Ewen Posted April 20, 2008 Share Posted April 20, 2008 Take a boat X, this boat carries 20,000 litres of diesel. Its designed to plane, and it can do 35 knots fully fuelled. If the owner hooned around at 35 knots, hed be out of fuel after 300 miles. If however, he slobbed around off the plane at 10 knots, he would manage closer to 1200 miles. Two things are in play here, one, at high speed the boat is very efficient as far as how fast it can go versus the overal weight...well done to the designer, shame on the owner for not caring about the consumption....two, at low speed, the hull isnt that efficient off-plane compared to others designed to go slower speeds from day one...well done to the owner for watching the consumption, shame on the designer for going for max performance ability and compromising the slow speed consumption. Theres obviously more economical motor yacht designs, but Ive used a planing hull as a typical type. Its a fact that around the 10 / 15 knot range (the typical, boring cruising speed for many large motor yachts for maximum range) there are many sailing yachts that will offer the same speed and faster, no fuel consumption and more fun at the same time. At the moment, its customer choice...maybe one day they wont have a choice. Link to comment Share on other sites More sharing options...
Ewen Posted April 20, 2008 Share Posted April 20, 2008 Ewen isn't there a ship that has 3 metal wing sails out there? Big-ass cargo ship or something...probably Japanese... Yes, Im trying to find a pic of her as we type Alex. Link to comment Share on other sites More sharing options...
Alex Posted April 20, 2008 Share Posted April 20, 2008 Yes, Im trying to find a pic of her as we type Alex. I'm failing to do that too.... Link to comment Share on other sites More sharing options...
RedM Posted April 20, 2008 Author Share Posted April 20, 2008 Ewen, Those massive super-yachts, the ones favoured by billionaires and the like. Could a luxurious vessel like that ever be powered by sail. I'm assuming that the size and weight isn't an issue but what about the leaning that wind-powered boats suffer from? Can that be countered? Link to comment Share on other sites More sharing options...
dangerous brain Posted April 20, 2008 Share Posted April 20, 2008 I think that happened around 17th century? Yeah but it was hardly reliable. Combustion engines proved to be way more reliable and technology couldn't manage 40 odd knots in a galleon. These days material tech is leaping along. Theres a new war going on in the world that people don't consider. Corporate war and the man with the best tech wins and gets all the money. Link to comment Share on other sites More sharing options...
Pete Posted April 20, 2008 Share Posted April 20, 2008 Can that be countered? http://travel.howstuffworks.com/sailboat5.htm Link to comment Share on other sites More sharing options...
Pete Posted April 20, 2008 Share Posted April 20, 2008 Yeah but it was hardly reliable. Combustion engines proved to be way more reliable and technology couldn't manage 40 odd knots in a galleon. These days material tech is leaping along. Theres a new war going on in the world that people don't consider. Corporate war and the man with the best tech wins and gets all the money. Ah well..you didn't specify you were in a hurry. Link to comment Share on other sites More sharing options...
Ewen Posted April 20, 2008 Share Posted April 20, 2008 Ewen, Those massive super-yachts, the ones favoured by billionaires and the like. Could a luxurious vessel like that ever be powered by sail. I'm assuming that the size and weight isn't an issue but what about the leaning that wind-powered boats suffer from? Can that be countered? Maltese Falcon ((280 feet, it can do almost 20 knots, pic below) is a true Superyacht in the accepted sense, and the same technology could be applied to bigger yachts...they would all lean though, and they would require a substantial keel. A twin-hull or tripple hulled Superyacht would lean far less under sail, but the overall beam would be colossal. Link to comment Share on other sites More sharing options...
AndyT Posted April 20, 2008 Share Posted April 20, 2008 Quick question Ewen. I've heard "the more hull in the water the quicker it goes" hence two or three hulls equals better performance. Is this a fallacy mate? Link to comment Share on other sites More sharing options...
Ewen Posted April 20, 2008 Share Posted April 20, 2008 Quick question Ewen. I've heard "the more hull in the water the quicker it goes" hence two or three hulls equals better performance. Is this a fallacy mate? I've limited knowledge when it comes to sailing boat design Andy, but Ive not heard that maxim before. With fast powered craft, the LESS hull in the water the better for higher speeds...ultimately to the extent that they plane on top of the water (or even hydrofoil as mentioned earlier). A sailing boat does not normally plane, so the amount of hull in the water stays pretty much the same whatever speed its doing. For hulls like this, another additional factor is the ratio between waterline length against waterline beam...generally, the longer the hull length compared to its beam, the faster it can go for a given power. Multi-hulled sailing boats offer two main advantages over mono hulled ones... One, the extra stability from the additional hull / hulls allow larger sail area for less keel weight (Im generalising here, hopefully Im not too far off), and two, the individual hulls have a much narrower beam for their length, which will allow higher speed. Link to comment Share on other sites More sharing options...
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