We now experience fierce competition between different concepts:-sliding on the surface - planing hulls and boats_ foiling on under water wing.-sail, blade like wing or kite to power.
But what could be ultimate sailing craft the could beat all those in next 30-50 years from now ? In may imagination that will be combination of kite and reverse foil.Kite will provide unlimited force which can no longer be possible to control by weight and gravity force.The only way is wing like foil design now to pull down not up.

I can imagine the sailor or kiter will be hanging comfortably in the seat 3 or 5 meters above the water level. Foil in the water will be remotely operated to keep exact optimal depth all the time. Powerful kite above at surface well above what is possible today to control.In fact this future kite most likely looks like a rigid blade or wing for future aerodynamic efficiency.

Now if somebody live long enough or could check in next 30 years if my prognosis was right.

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Macroscien said..
We now experience fierce competition between different concepts:-sliding on the surface - planing hulls and boats_ foiling on under water wing.-sail, blade like wing or kite to power.
But what could be ultimate sailing craft the could beat all those in next 30-50 years from now ? In may imagination that will be combination of kite and reverse foil.Kite will provide unlimited force which can no longer be possible to control by weight and gravity force.The only way is wing like foil design now to pull down not up.

I can imagine the sailor or kiter will be hanging comfortably in the seat 3 or 5 meters above the water level. Foil in the water will be remotely operated to keep exact optimal depth all the time. Powerful kite above at surface well above what is possible today to control.In fact this future kite most likely looks like a rigid blade or wing for future aerodynamic efficiency.

Now if somebody live long enough or could check in next 30 years if my prognosis was right.

Kind of like Sailrocket with a kite. There could be all sorts of computer chip 'fly by wire' controls that may make it work. You could well be close to it.
I certainly plan to check your forecast Macro.

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Macroscien said..
We now experience fierce competition between different concepts:-sliding on the surface - planing hulls and boats_ foiling on under water wing.-sail, blade like wing or kite to power.
But what could be ultimate sailing craft the could beat all those in next 30-50 years from now ? In may imagination that will be combination of kite and reverse foil.Kite will provide unlimited force which can no longer be possible to control by weight and gravity force.The only way is wing like foil design now to pull down not up.

I can imagine the sailor or kiter will be hanging comfortably in the seat 3 or 5 meters above the water level. Foil in the water will be remotely operated to keep exact optimal depth all the time. Powerful kite above at surface well above what is possible today to control.In fact this future kite most likely looks like a rigid blade or wing for future aerodynamic efficiency.

Now if somebody live long enough or could check in next 30 years if my prognosis was right.

From Scientific American, The Amateur Scientist, 1975 miriam-english.org/files/ultimate-sailing-rig-without-hull/The%20Ultimate%20in%20Sailing%20is%20a%20Rig%20Without%20a%20Hull.html

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Macroscien said..
The only way is wing like foil design now to pull down not up.

Why wait 30 years - that is exactly how SailRocket works... not even as of today... aka a few years ago.

...so I think you have good post-prognosis.

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Pacey said..

Macroscien said..
We now experience fierce competition between different concepts:-sliding on the surface - planing hulls and boats_ foiling on under water wing.-sail, blade like wing or kite to power.
But what could be ultimate sailing craft the could beat all those in next 30-50 years from now ? In may imagination that will be combination of kite and reverse foil.Kite will provide unlimited force which can no longer be possible to control by weight and gravity force.The only way is wing like foil design now to pull down not up.

I can imagine the sailor or kiter will be hanging comfortably in the seat 3 or 5 meters above the water level. Foil in the water will be remotely operated to keep exact optimal depth all the time. Powerful kite above at surface well above what is possible today to control.In fact this future kite most likely looks like a rigid blade or wing for future aerodynamic efficiency.

Now if somebody live long enough or could check in next 30 years if my prognosis was right.

From Scientific American, The Amateur Scientist, 1975 miriam-english.org/files/ultimate-sailing-rig-without-hull/The%20Ultimate%20in%20Sailing%20is%20a%20Rig%20Without%20a%20Hull.html

Fantastic ! Because this is absolutely the same idea. Which means that good concepts never die, just waiting for their time,Like Electric Cars had to wait a whole century for their renaissance ( and found their prorok in Elon Musk).Obviously this ultimate sailing machine now will incorporate everything we now know about aerodynamic and water flow.
The best so far is fat wing, airfoil for lift, propulsion.So we could create light wing structure filled with helium to be almost weightless. Thin carbon structure as the latest solar planes use.
Foil - close to recently used in our water sports but with active controls.Most likely electronics taking care about depth , angle of attack, surface area, maybe swing back at speed and obviously with winglets to deal with turbulence.

( I still wonder why nobody cares to do speed fin with winglets !!?? So obvious . If I have any skills in doing carbon fibre fin I will do this for free for you guys to try and bear world records. Winglets are beneficials for speed records because they do work only in one direction. Winglets on our fins - our fin is bent at the angle at very end at near 90 degree for few cm. The main purpose for our winglets is not only provide lift UP , to rise a board but deal with with terrible turbulence that limit our max speed. I thought the the easiest could be bent fin made of steel, but we still need somebody brave to use such fin made of steel and sharp as damascus sword. Because I had some nasty experience recently with Chainsaw cutting trough my plain trousers - I do advice use some protection for sailing with steel fins. Maybe boots from ski shop and kevlar pants from Stihl?? )

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Macroscien said..
Which means that good concepts never die, just waiting for their time,Like Electric Cars had to wait a whole century for their renaissance

The concept of an electric-car, is not interesting in its own right... who cares how a personalised-transport-device is propelled ?!? .... what matters is the end result. It was the limitations of material-science that limited electric-cars to specialised cases [ up until about 20-30 yrs ago ] -> electric cars were never a good concept for mass market.

Its the advancement in material-sciences that changed the status quo. For personalised-transport, the energy-density of batteries (and fuel-cells, etc) increased to the point where other advances in efficiency - such as neodymium-magnet-motors, carbon fibre body panels, etc - all contributed to make a compelling transportation device.

I want my ionic-wind self-flying craft so that I dont have to listen to an engine... [ and not be limited to roads ]. I am unlikely to see that anytime soon because energy-density needed for ionic-wind is incredibly high.

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mathew said..

Macroscien said..
Which means that good concepts never die, just waiting for their time,Like Electric Cars had to wait a whole century for their renaissance

The concept of an electric-car, is not interesting in its own right... who cares how a personalised-transport-device is propelled ?!? .... what matters is the end result. It was the limitations of material-science that limited electric-cars to specialised cases [ up until about 20-30 yrs ago ] -> electric cars were never a good concept for mass market.

Its the advancement in material-sciences that changed the status quo. For personalised-transport, the energy-density of batteries (and fuel-cells, etc) increased to the point where other advances in efficiency - such as neodymium-magnet-motors, carbon fibre body panels, etc - all contributed to make a compelling transportation device.

I want my ionic-wind self-flying craft so that I dont have to listen to an engine... [ and not be limited to roads ]. I am unlikely to see that anytime soon because energy-density needed for ionic-wind is incredibly high.

If you ionic craft will be fast you will still must deal with wind noise. The problem we have now with electric cars is lack of that noise , to warn pedestrians. I guess that popular subwoofers now should be installed outside, and speakers could recreate any noise you like. Jet engine, horse, bicycle, HarleyD, etc. Similar with foil sail boards today. Luckily problem possibly resolved by whistling sound generated by mast extension (?) Some foilers now are more noisy then riding on chop speed boards.

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Macroscien said..
If you ionic craft will be fast you will still must deal with wind noise. The problem we have now with electric cars is lack of that noise , to warn pedestrians. I guess that popular subwoofers now should be installed outside, and speakers could recreate any noise you like. Jet engine, horse, bicycle, HarleyD, etc. Similar with foil sail boards today. Luckily problem possibly resolved by whistling sound generated by mast extension (?) Some foilers now are more noisy then riding on chop speed boards.

You must not have been in an electric car - they are definitely noisy - they sound like a sewing machine (or model-electric-plane, or a turbine). They are just orders of magnitude quieter than a piston engine.

The lack of noise for pedestrians, is a problem. Humans have become used to using their hearing, to determine if a vehicle is approaching - we used to listen for horse-hooves, and thus people were run down by the first motor-cars. ** Modern cars (not electric) are very quiet, so the red-paint still occurs anyway. It will take time, but people will get stop looking at their phones before crossing the street.

** Which is why there was (is?) a law requiring people to walk in front of their vehicle holding a red flag: www.mentalfloss.com/article/71555/ridiculous-uk-traffic-laws-yore

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Macroscien said.( I still wonder why nobody cares to do speed fin with winglets !!?? So obvious .

You need to study hydro/aerodynamic a bit more.
Winglets work by reducing the tip vortex as a proportion of the total drag.
Tip vortex drag is proportional to the Coef. Lift, which is proportional to the angle of attack.
The greater the AoA= greater the tip vortex drag.
Speed foils work at low AoA so not much tip vortex drag. This is why fighter jet don't have winglets but slower commercial jets do.

But on the question of lift there may be a benefit with small tip winglets. Slowie tried this a decade or so ago. I think he felt some benefit but not enough to pursue.

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yoyo said..

Macroscien said.( I still wonder why nobody cares to do speed fin with winglets !!?? So obvious .

You need to study hydro/aerodynamic a bit more.
Winglets work by reducing the tip vortex as a proportion of the total drag.
Tip vortex drag is proportional to the Coef. Lift, which is proportional to the angle of attack.
The greater the AoA= greater the tip vortex drag.
Speed foils work at low AoA so not much tip vortex drag. This is why fighter jet don't have winglets but slower commercial jets do.

But on the question of lift there may be a benefit with small tip winglets. Slowie tried this a decade or so ago. I think he felt some benefit but not enough to pursue.

Shorter fins - shallower water - ground effect ?

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NotWal said..
Shorter fins - shallower water - ground effect ?

I think so, especially in thick weed.

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NotWal said..



Shorter fins - shallower water - ground effect ?

Plural fins on the one board. Ground effect takes care of gravity but you still have to throw enough water sideways to counteract the lateral component of sail lift. One short fin can only throw so much water. If the fins just graze the bottom you won't have tip vortices to worry about, Ground effect works for fins as well if they can skim the bottom the deflected water interacts with mother earth. But boards will have to be wider so side by side fins don't overly interact. Maybe multihulls? I think there's much more to be got out of even shallower water.

There could be a bit to be gained by using asymmetric speed boards in shallow water. Water deflected by the hull and fin combination needs to counteract the sum of gravity and lateral sail reaction. Throwing water upwind is not beneficial. Kite boarders are a better off in this regard throwing very little water directly upwind. If windsurfers had a strongly curled down windward rail, like that kite board edge, it would further minimise water being deflected windward. In very shallow water you'd aim to leave an almost dry wake. We've got asymmetric fins, asymmetric sails, asymmetric booms. Why do we have symmetric boards???

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You need to study hydro/aerodynamic a bit more.
Winglets work by reducing the tip vortex as a proportion of the total drag.
Tip vortex drag is proportional to the Coef. Lift, which is proportional to the angle of attack.
The greater the AoA= greater the tip vortex drag.
Speed foils work at low AoA so not much tip vortex drag. This is why fighter jet don't have winglets but slower commercial jets do.

But on the question of lift there may be a benefit with small tip winglets. Slowie tried this a decade or so ago. I think he felt some benefit but not enough to pursue.

Tip vortex drag (induced drag) is dependent on coefficient of lift / angle of attack, but these are dependent on velocity and fin area. Induced drag is also heavily dependent on span.

Speed sailors use fins of smaller area for high speed conditions, and paricularly they use fins that are shorter for high speed boards, due to limits on the leverage available on a narrow board to counteract the heeling moment of the fin.

So the reality is that speed fins often work at reasonably high angles of attack, even at high speeds at places like luderitz, due to loads encountered in gusts and chop.

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Pacey said..

So the reality is that speed fins often work at reasonably high angles of attack,

Can you give us a number ? It wouldn't be as high as 7 degrees would it? The number curves you can find on the internet suggest for best L/D

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Ian K said..

Pacey said..

So the reality is that speed fins often work at reasonably high angles of attack,

Can you give us a number ? It wouldn't be as high as 7 degrees would it? The number curves you can find on the internet suggest for best L/D

I dont know, but i have to admit to being surprised at the high leeway angles you can see on boards sailing the Luderitz course in gusty conditions and during the acceleration phase early in the run. The fins look they are sized to be optimal at over 50 knots, but look like they are sub-optimal below that.

I am just to another idea.Did somebody try already two fins instead of one? But not like popular wave boards.Using two fins - one in front , another at the back would create enormous turning moment.So our angle of attack could be minimized below this fatal 7 degree (?)We may have 3 options:1. Two smaller fins in line. The problem could be that second find travel in the wave/wake of the first2 Two fins but lateral position . One leading in front by several cm and one to the back We could avoid disturbance from front fin .this combination will be asymmetrical - works better on in one direction.3.Fin with long hole along, isided fin. So instead of fin 10 cm width we would have 2-3 cm material hole 5- 10 cm and another fin surface.This combination could be quite interesting in real life experiment. Because rear surface will travel in the wave/ turbulence created by leading surface. Like two sails on your yacht that works better than a single one. Maybe construction will need a lot of tests because any change in this distance/ hole inside and position of those two surfaces may create tremendous difference in performance.I imagine that to test our fin the best method will be creating rail and running along 50m swimming pool or long artificial tank/ channel with water.We could run our wagon at 50 knotts and measure all parameters to test our fins.

There's a kitefoiler who lives locally and he's out at marmong regularly on his foil board and 18 metre kite. There is nothing on the water that even comes remotely close to possibly contemplating the insignificant possibility that perhaps one day someone might get close to him. It's truly awesome to watch this guy doing close to 30 knots in about 10 knots of wind and pushing 40 knots in the chop when the wind picks up. Don't get me wrong, this bloke is a red hot sailor but still, this kind of performance was unthinkable 25 years ago. It hadn't even entered our heads.

Now skip ahead another 25 years. Will things have progressed the same amount? will it be something we can't even contemplate now? whats the advancement curve here? will it continue, accelerate or plateau?

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Cluffy said..
It hadn't even entered our heads.

It has - Macquarrie Innovation only made use of the low-20's to do 50 knots.

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Cluffy said..
There's a kitefoiler who lives locally and he's out at marmong regularly on his foil board and 18 metre kite. There is nothing on the water that even comes remotely close to possibly contemplating the insignificant possibility that perhaps one day someone might get close to him. It's truly awesome to watch this guy doing close to 30 knots in about 10 knots of wind and pushing 40 knots in the chop when the wind picks up. Don't get me wrong, this bloke is a red hot sailor but still, this kind of performance was unthinkable 25 years ago. It hadn't even entered our heads.

Now skip ahead another 25 years. Will things have progressed the same amount? will it be something we can't even contemplate now? whats the advancement curve here? will it continue, accelerate or plateau?

Cluffy are those speeds of 30 and 40 kts your eyeball estimations or are they GPS verified?

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Cluffy said..
There's a kitefoiler who lives locally and he's out at marmong regularly on his foil board and 18 metre kite. There is nothing on the water that even comes remotely close

Probably half a dozen here. Practicing every evening till the sun goes down, (they must be young enough to be in the work force). The exact distance of the LOC may be in dispute but the straight line 19 km from Rottnest lighthouse to Leighton is not. 18 min 45 secs.

www.perthnow.com.au/sport/new-record-set-in-lighthouse-to-leighton-kiteboard-race-in-perth-ng-b881044504z

I'd only first sighted these high aspect foil kites this summer. Still room for improvement you'd think.

If you were a young bloke, not from a windsurfing family, but into speed, cashed up, with a fascination for extracting the best from wind and water, this is the direction you'd go. The windsurfing genre looks set to collapse into just wave sailing.