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This is CRAZY. How fast are you going(estimated). I have never even been that fast in the water PERIOD…except for a ski boat, but that is a boat. Were you shitting your pants? I would!!
Also, in reviewing the video again, I notice that the hydrofoil is placed far aft of the center of gravity, so I would suspect that the a great deal of the sail energy is lost by the hydrofoil needing to create gobs of extra lift to counter act the board/sail/rider’s weight well forward of the hydrofoil. I know the sail generates some vertical lift, but I suspect not nearly enough to counteract the placement of the hydrofoil.
i think its cool for trimarans. though the only benefit is speed (not even sure). You don’t have the real surf feeling, playing with the waves etc. what does it add besides some possible speed benefits?
Interesting discussion about the theories of tradional vs. hydrofoil board speeds.
On this video, I would offer two thoughts:
1) Intuitively, it appears that a properly designed hydrofoil board with a designed sail should be faster due to less water resistance.
2) In this video, I think part of the story is that the traditional board APPEARS to catch up because the point of view of is rotating as the sailors pass the buoy. Perhaps the traditional board is faster, but it’s not clear.
The foil used for these is a very inefficient low aspect ratio foil that originated for waterskis and the “airchair”.
They have a large amount of induced drag and form drag for a hydrofoil. ie, not ideal. The other sailboard has less foil in the water and very similar wetted surface plus highly aerated water in contact due to surface chop. The planing board has a higher speed potential for the same sea and wind conditions. Improving the foil design would help but these are dudes not scientists
The surface sealing effect yes is significant, but the resistance from the hydrofoil is SO MUCH less … doesn’t explain fully why hydrofoiled guy slower. Lot has to do with the elevated board gives elevated point of thrusting forces to act, and the reactionary forces, below the water are also lowered, this created a huge capsizing moment, so thust from the sail has to be reduced in order to stay upright, and that is why the guy that over took the foil could use a much larger sail, noticed?
Another reason the foil may be slower, on a conventional board - you can ‘close the slot’ ie bring the foot of the sail down to the board and stop the wind going under, giving you a speed increase. With the foil the wind will just go under the board.
so you are saying that the hydrofoil decreases the resistance between the keel and the water, therefore the entire rig cannot capture as much power as if the board was planing.
hi yes it is the air on the sail that solely affects the speed (with air) the only difference it being out of the water is there is less resistance because it is not pushing the water slightly
but doesnt the hydrofoil lift the board out? why would the air under the keel affect the speed of the boat, i mean even if it does lift the board up out of the water, isn’t the important air the stuff thats captured in the sail, because that is what is pushing the windsurf forward. air under the keel usually doesnt propel a windsurf board because it is usually planing, not foiling.
The wind has its resistance. Planes use wings and rudder to drag air and take a direction in the same way water does.
However, if too much airpressure is captured under the keel that would be counterproductive. It would lift the board rather than pushing it ahead by reducing the speed. Also, to manage such lift you would have to use a smaller sail. Look at the video, see how the conventional surfer goes faster?
March 26th, 2008 at 2:09 pm
is there something attached to the fin?
March 29th, 2008 at 5:46 pm
This is CRAZY. How fast are you going(estimated). I have never even been that fast in the water PERIOD…except for a ski boat, but that is a boat. Were you shitting your pants? I would!!
March 31st, 2008 at 10:48 am
automaticreply - Another good point.
Also, in reviewing the video again, I notice that the hydrofoil is placed far aft of the center of gravity, so I would suspect that the a great deal of the sail energy is lost by the hydrofoil needing to create gobs of extra lift to counter act the board/sail/rider’s weight well forward of the hydrofoil. I know the sail generates some vertical lift, but I suspect not nearly enough to counteract the placement of the hydrofoil.
Other thoughts?
April 2nd, 2008 at 7:59 am
also we don’t know the weight of the riders or the size of their sails.
April 5th, 2008 at 2:48 pm
i think its cool for trimarans. though the only benefit is speed (not even sure). You don’t have the real surf feeling, playing with the waves etc. what does it add besides some possible speed benefits?
April 5th, 2008 at 4:51 pm
did u gwt thet from the boondocks
April 6th, 2008 at 9:43 pm
if you can control the foil angle and height I bet you could go a lot faster?
April 8th, 2008 at 9:20 am
Interesting discussion about the theories of tradional vs. hydrofoil board speeds.
On this video, I would offer two thoughts:
1) Intuitively, it appears that a properly designed hydrofoil board with a designed sail should be faster due to less water resistance.
2) In this video, I think part of the story is that the traditional board APPEARS to catch up because the point of view of is rotating as the sailors pass the buoy. Perhaps the traditional board is faster, but it’s not clear.
April 9th, 2008 at 8:33 pm
sexy why they not in the shop no good ha
April 10th, 2008 at 11:12 am
That was bloody cool.
April 13th, 2008 at 10:10 pm
jesus youre smart man did you mum tell you that
April 15th, 2008 at 10:40 pm
THAT IS SICK!!!!!
April 16th, 2008 at 2:56 pm
esto da gusto verlo….arriba windsurf!
April 19th, 2008 at 6:56 am
English mother fucker, do you speak it!
April 21st, 2008 at 3:04 pm
?????????
April 24th, 2008 at 4:58 pm
The foil used for these is a very inefficient low aspect ratio foil that originated for waterskis and the “airchair”.
They have a large amount of induced drag and form drag for a hydrofoil. ie, not ideal. The other sailboard has less foil in the water and very similar wetted surface plus highly aerated water in contact due to surface chop. The planing board has a higher speed potential for the same sea and wind conditions. Improving the foil design would help but these are dudes not scientists
April 26th, 2008 at 10:57 pm
The conventional board in the background appears to be going faster! How is this an improvement on a standard board and why?
April 29th, 2008 at 5:24 pm
The surface sealing effect yes is significant, but the resistance from the hydrofoil is SO MUCH less … doesn’t explain fully why hydrofoiled guy slower. Lot has to do with the elevated board gives elevated point of thrusting forces to act, and the reactionary forces, below the water are also lowered, this created a huge capsizing moment, so thust from the sail has to be reduced in order to stay upright, and that is why the guy that over took the foil could use a much larger sail, noticed?
May 2nd, 2008 at 3:02 am
he looks relaxed…
May 4th, 2008 at 6:09 am
he looks relaxed…
May 7th, 2008 at 12:05 pm
Another reason the foil may be slower, on a conventional board - you can ‘close the slot’ ie bring the foot of the sail down to the board and stop the wind going under, giving you a speed increase. With the foil the wind will just go under the board.
May 9th, 2008 at 2:56 pm
so you are saying that the hydrofoil decreases the resistance between the keel and the water, therefore the entire rig cannot capture as much power as if the board was planing.
May 11th, 2008 at 2:24 am
hi yes it is the air on the sail that solely affects the speed (with air) the only difference it being out of the water is there is less resistance because it is not pushing the water slightly
May 14th, 2008 at 2:03 am
ok, thanks, i kinda get what you are saying.
but doesnt the hydrofoil lift the board out? why would the air under the keel affect the speed of the boat, i mean even if it does lift the board up out of the water, isn’t the important air the stuff thats captured in the sail, because that is what is pushing the windsurf forward. air under the keel usually doesnt propel a windsurf board because it is usually planing, not foiling.
May 16th, 2008 at 8:52 am
The wind has its resistance. Planes use wings and rudder to drag air and take a direction in the same way water does.
However, if too much airpressure is captured under the keel that would be counterproductive. It would lift the board rather than pushing it ahead by reducing the speed. Also, to manage such lift you would have to use a smaller sail. Look at the video, see how the conventional surfer goes faster?