Bouke-Witchcraft said..

SchobiHH said..

Bouke-Witchcraft said..
Physical laws tell us that width is more important than length. More efficient. Look at the wings of sail planes or windmills. But there are other important factors. If you make a shorter board with the same total amount of rocker, it will have more curvature, thus drag more when getting planing. OTOH, for wave sailing, a longer board needs more total amount of rocker not to bury the nose and turn as well, so in fact have the same amount of curvature. Another really important and often overlooked factor is foot strap placement to adjust the trim angle. It has become fashion to place the straps quite far to the back. Moving the straps forward makes a big change to early planing, even more so for less skilled riders who are not as good in using mast foot pressure to keep the trim angle low. (BTW, for very big or tall riders often the boom cut out is (too) low, moving the boom up also helps to give MFP) By moving the straps forward you are increasing the planing area and especially the tail area. But in float n ride DTL riding there is hardly any sail pressure to convert into MFP so there it is also a good thing for skilled riders, given that the board has enough rocker to turn well. Or if you find the board slow and dull, moving the straps back just one position can totally change the board, make it faster and looser. Its happened various times that I gave such advice to customers and then hearing: I should have known that years ago.

"Physical laws tell us"? What do you know about physical laws? Everything I read from you doesn't make my believe that you have any.

Question: Why are airplane, windturbine or sail plane wings long (perpendicular to the flow=width with boards) and narrow (with the flow=length with boards)? I guess they are all developed wrong than eh? Why didn?t they listen to you? And we can go on to Formula boards, foils etc. etc.

If you would know something about physics than you would know the answer. But you have no shame to talk about physics... Simply tell me the governing physical law which backs your statement.

Bouke-Witchcraft said..

SchobiHH said..

Bouke-Witchcraft said..

SchobiHH said..

Bouke-Witchcraft said..
Physical laws tell us that width is more important than length. More efficient. Look at the wings of sail planes or windmills. But there are other important factors. If you make a shorter board with the same total amount of rocker, it will have more curvature, thus drag more when getting planing. OTOH, for wave sailing, a longer board needs more total amount of rocker not to bury the nose and turn as well, so in fact have the same amount of curvature. Another really important and often overlooked factor is foot strap placement to adjust the trim angle. It has become fashion to place the straps quite far to the back. Moving the straps forward makes a big change to early planing, even more so for less skilled riders who are not as good in using mast foot pressure to keep the trim angle low. (BTW, for very big or tall riders often the boom cut out is (too) low, moving the boom up also helps to give MFP) By moving the straps forward you are increasing the planing area and especially the tail area. But in float n ride DTL riding there is hardly any sail pressure to convert into MFP so there it is also a good thing for skilled riders, given that the board has enough rocker to turn well. Or if you find the board slow and dull, moving the straps back just one position can totally change the board, make it faster and looser. Its happened various times that I gave such advice to customers and then hearing: I should have known that years ago.

"Physical laws tell us"? What do you know about physical laws? Everything I read from you doesn't make my believe that you have any.

Question: Why are airplane, windturbine or sail plane wings long (perpendicular to the flow=width with boards) and narrow (with the flow=length with boards)? I guess they are all developed wrong than eh? Why didn?t they listen to you? And we can go on to Formula boards, foils etc. etc.

If you would know something about physics than you would know the answer. But you have no shame to talk about physics... Simply tell me the governing physical law which backs your statement.

There is not one single law but a combination of laws as I have learned from aerodynamic or hydrodynamic experts I have worked with over the years. Which in the end are physical laws. It is also common knowledge nowadays that also in wave boards, width is the most important parameter to compare to judge a boards range, after that comes tailwidth, length, rocker and volume in no particular order. Also that is a result of physical laws, even without knowing the exact laws. The important thing is to know the result. But maybe that is all wrong and I am always happy to learn something new. So please share your infinite wisdom with us.

If they were experts they clearly wouldn't have told you that nonsence. That means that have made it up. And this is exactly what I am saying. You know nothing about the laws behind it. So please don't use "the physical laws tell us" in your statements. Thats bold and ignorant to the experts out there in the world. I could explain you difference, but why should I? It doesn't help anyway telling you. You are the most ignorant person when it comes to your "fake" theories you try to spread into the world. you are like a flat earther. Discussion sense less. (And I am allowed to this statement because I am a physicist and mathematician with a master degree.)

SchobiHH said..

Bouke-Witchcraft said..

SchobiHH said..

Bouke-Witchcraft said..

SchobiHH said..

Bouke-Witchcraft said..
Physical laws tell us that width is more important than length. More efficient. Look at the wings of sail planes or windmills. But there are other important factors. If you make a shorter board with the same total amount of rocker, it will have more curvature, thus drag more when getting planing. OTOH, for wave sailing, a longer board needs more total amount of rocker not to bury the nose and turn as well, so in fact have the same amount of curvature. Another really important and often overlooked factor is foot strap placement to adjust the trim angle. It has become fashion to place the straps quite far to the back. Moving the straps forward makes a big change to early planing, even more so for less skilled riders who are not as good in using mast foot pressure to keep the trim angle low. (BTW, for very big or tall riders often the boom cut out is (too) low, moving the boom up also helps to give MFP) By moving the straps forward you are increasing the planing area and especially the tail area. But in float n ride DTL riding there is hardly any sail pressure to convert into MFP so there it is also a good thing for skilled riders, given that the board has enough rocker to turn well. Or if you find the board slow and dull, moving the straps back just one position can totally change the board, make it faster and looser. Its happened various times that I gave such advice to customers and then hearing: I should have known that years ago.

"Physical laws tell us"? What do you know about physical laws? Everything I read from you doesn't make my believe that you have any.

Question: Why are airplane, windturbine or sail plane wings long (perpendicular to the flow=width with boards) and narrow (with the flow=length with boards)? I guess they are all developed wrong than eh? Why didn?t they listen to you? And we can go on to Formula boards, foils etc. etc.

If you would know something about physics than you would know the answer. But you have no shame to talk about physics... Simply tell me the governing physical law which backs your statement.

There is not one single law but a combination of laws as I have learned from aerodynamic or hydrodynamic experts I have worked with over the years. Which in the end are physical laws. It is also common knowledge nowadays that also in wave boards, width is the most important parameter to compare to judge a boards range, after that comes tailwidth, length, rocker and volume in no particular order. Also that is a result of physical laws, even without knowing the exact laws. The important thing is to know the result. But maybe that is all wrong and I am always happy to learn something new. So please share your infinite wisdom with us.

If they were experts they clearly wouldn't have told you that nonsence. That means that have made it up. And this is exactly what I am saying. You know nothing about the laws behind it. So please don't use "the physical laws tell us" in your statements. Thats bold and ignorant to the experts out there in the world. I could explain you difference, but why should I? It doesn't help anyway telling you. You are the most ignorant person when it comes to your "fake" theories you try to spread into the world. you are like a flat earther. Discussion sense less. (And I am allowed to this statement because I am a physicist and mathematician with a master degree.)

Hmm, I wonder who is the flat earther? Because everything I have said you can see all around us, even if you dont have a masters degree. Any experienced windsurfer knows that width is more important than length or volume, there is nothing shocking about stating that. And windsurfing is all about physical laws. So there is absolutely nothing wrong about what I said. I dont care about masters degrees, I care about stuff that works and for things I do not know myself, I search for people who can help me. If what they said didn?t work, I would have stopped using it. I have worked with various experts in aero or hydrodynamics who were, are or went on to work for big companies in this field like Airbus, windturbine or Naval architect companies and even becoming the boss there. You dont become the boss in such companies if your theories dont work. I have some of such people amongst my customers and also had students in this field as interns to do research for me and some have made a steep career since. There were also some who were pretty useless, which makes one think how much a masters degree is worth. If your theory says different, please explain and with proof. Untill proven, a theory is only a theory. When a theory is proven right, it turns into a law. If you cant question a theory or science, it is not science it is propaganda. So it is fine to question what I said. But maybe in a more reasonable way? I dont know why but between the lines your words radiate so much hate that it seems to prevent you to have a normal discussion. If you have proof or a theory about how it is, please share it, I am all ears but in a normal adult tone please, even if you hide behind a nickname.

Mmmm Have we forgotten about formula boards? If I understand Bourke correctly he is saying a wider board will plane earlier? All things being equal that is correct. A wider board has a higher aspect planning surface. The bulk of the lift is being produced at the leading edge of a planing surface as the water flows towards the rear of the board it also starts to flow outward. The closer to the tail the less lift is created .
Assuming there is no major differences in rocker, volume etc a wider shorter planing surface will generate more lift than a longer narrower planing surface of equal area. Parastic drag is impacted mainly by the surface area so that is equal.
Yes I know his is over simplistic as there are so many other factors...

Yep It's all about width. A windsurfer is a planning hull, not a displacement hull and a higher aspect planning surface has less drag. The hump isn't a concern as we can just bounce the board over it by pumping.

plenty of books written about this from the 1940's and on.

Mark _australia said..
No argument there.
My issue is likening it to wings with the inference that a wide wing is better so a wide board must be also. That was such a strange statement

Well, a fin with a narrow chord will stall earlier than a fin wirh a wide chord, no?

Mark _australia said..
No argument there

My issues is a "wide board is better, look at wings"
Look at what?
A glider and a Edge540 and a F35 are all the same are they?

Its a silly statement. Then if anyone questions him, he yells that scientists advise him and nobody else knows anything about the science. He was the same in the fin thread.

Yes. It was another silly statement.

That's why I had KT:Quatro shape me this custom. It's basically a 118 liter Goya Quad, with paper thin rails. When it's flukey side to side-off, it's gold in the event I drop the sail and have too uphaul. It's the bomb on the wave up to about rib high crunchy closeouts and head high soft waves.

I'm 183cm tall (6") and weight 77kgs and a competent weekend wave sailor. Been short boarding in waves all my life , but in 2008 I had a serious cardiac problem that make me take betablockers daily ever since , to prevent my heartbeats to pass a certain threshold . The doctor said no more windsurfing for me. Well I could go on the flats but no more lightwind waves, too hard on BPMs. Especially when you have to cross white water on the way out, but also catching waves on the way in . I purchased the Exocet Kona 9.5 at the time, it saved me and became my most used board for the next 15 years. No more jumping obviously, but the easiness of the board made it possible for me to keep on going in waves and do turns. 125 liters, 300cm long and only 59cm wide, this thing is super long, super narrow in relation to its length, and incredibly easy and efficient to get going, uphaul , and catch waves. It planes better than most normal 95-105L freestyle waves boards in lightwind, and just the same in steady 20knots+ winds. It does not accelerate as quickly, more like a cadillac against a sportcar, but it is just as fast in a straight line. Now it doesn't turn as tight as my 84L Goya quad of course, the difference is like when surfing a shortboard vs surfing a longboard. It's different, but there is fun in using both. Some may argue that you don't use them in the same type of wave , it's true that when conditions get better I stay more on the flats , on the shoulder, the better the conditions the less likely I am going to try to hit the lip, but in mellower waves I can do stuff nobody else can do , kites and wingers included. Some would hate that kind of shape at first, although I think it is an acquired taste and everyone who struggle with finding a good float&ride board should try one before passing judgement. Like a shortboarder who struggle on crap waves should change his point of view and try a longboard instead. But if you live in Fuerteventura or any place with clean peeling waves and a channel to get back to the peak you don't need such boards.
Since then and hundreds of waves caught with my Kona my health got better, but I never got rid of the board. I actually have owned a spare one at a time. And now, just yesterday, I purchased the newer version just released, the Exocet Breeze 8'10", the slightly shorter slightly wider more modern version of the 9'5", same ducktail for the longer rail line when shlogging that makes this shape so bloody efficient , same volume that will keep me totally relaxed when crossing the white water and keep me fresh and not tired before attacking the next wave. The marketing blurb promises more maneuverability and same efficiency. Can't wait to try it.

Al1 said..
I'm 183cm tall (6") and weight 77kgs and a competent weekend wave sailor. Been short boarding in waves all my life , but in 2008 I had a serious cardiac problem that make me take betablockers daily ever since , to prevent my heartbeats to pass a certain threshold . The doctor said no more windsurfing for me. Well I could go on the flats but no more lightwind waves, too hard on BPMs. Especially when you have to cross white water on the way out, but also catching waves on the way in . I purchased the Exocet Kona 9.5 at the time, it saved me and became my most used board for the next 15 years. No more jumping obviously, but the easiness of the board made it possible for me to keep on going in waves and do turns. 125 liters, 300cm long and only 59cm wide, this thing is super long, super narrow in relation to its length, and incredibly easy and efficient to get going, uphaul , and catch waves. It planes better than most normal 95-105L freestyle waves boards in lightwind, and just the same in steady 20knots+ winds. It does not accelerate as quickly, more like a cadillac against a sportcar, but it is just as fast in a straight line. Now it doesn't turn as tight as my 84L Goya quad of course, the difference is like when surfing a shortboard vs surfing a longboard. It's different, but there is fun in using both. Some may argue that you don't use them in the same type of wave , it's true that when conditions get better I stay more on the flats , on the shoulder, the better the conditions the less likely I am going to try to hit the lip, but in mellower waves I can do stuff nobody else can do , kites and wingers included. Some would hate that kind of shape at first, although I think it is an acquired taste and everyone who struggle with finding a good float&ride board should try one before passing judgement. Like a shortboarder who struggle on crap waves should change his point of view and try a longboard instead. But if you live in Fuerteventura or any place with clean peeling waves and a channel to get back to the peak you don't need such boards.
Since then and hundreds of waves caught with my Kona my health got better, but I never got rid of the board. I actually have owned a spare one at a time. And now, just yesterday, I purchased the newer version just released, the Exocet Breeze 8'10", the slightly shorter slightly wider more modern version of the 9'5", same ducktail for the longer rail line when shlogging that makes this shape so bloody efficient , same volume that will keep me totally relaxed when crossing the white water and keep me fresh and not tired before attacking the next wave. The marketing blurb promises more maneuverability and same efficiency. Can't wait to try it.

Sounds really good, looking to hear how the new shape goes. Especially interested to hear if it handles steeper more critical waves better than the predecessor.

I have the old 10'5 (I'm 6'2 and 92/94 kg) and it's as you describe. Perfect for those less than perfect days. Once the waves get crunchy I switch to a 128 L Flikka custom. My biggest problem is not enough nose rocker in the 10'5 so lots of nose diving after big lip smacks in crunchy waves, hence the Flikka for those conditions.

Gestalt said..
Yep It's all about width. A windsurfer is a planning hull, not a displacement hull and a higher aspect planning surface has less drag. The hump isn't a concern as we can just bounce the board over it by pumping.

plenty of books written about this from the 1940's and on.

I don't know of any book. Maybe you can share your information sources. BTW AFAIK this is the main study that many refer to as the basis of planing hull empirical phycial relations. But this is from the 1964. www.boatdesign.net/attachments/hydrodynamic-design-of-planing-hulls-savitsky-1964-pdf.89527/
And this study is nothing else than accepting that we do not understand the governing laws in detail, therefore we need to do empirical laws, i.e. we assume some functional relationship and then fit the data with the curves.... Very useful in practice even it is not very satisfactory from a physical point of view.

Bouke-Witchcraft said..

Mark _australia said..
No argument there

My issues is a "wide board is better, look at wings"
Look at what?
A glider and a Edge540 and a F35 are all the same are they?

Its a silly statement. Then if anyone questions him, he yells that scientists advise him and nobody else knows anything about the science. He was the same in the fin thread.

Sorry guys, busy days over here, wind and waves every day and loads of customers.

The huge difference between a glider and an F35 is the amount of power. If you need to be power efficient, like us windsurfers also need to be, a wider, shorter board is more efficient. Like Mr Love also explained in different words. With any foil, the first part the medium we are in (water or air) makes contact with, provides the most power/lift. Off course there are other things to take into consideration like leverages and construction strength. With the amount of force of an F35, the wings of a glider would snap right off and with such speeds is not necesary either. With a very long and narrow windsurf sail, the leverage would get higher so harder to hold and the forces on the mast increase. With a board, once at speed more width becomes harder to put the rail (the leverage you can apply with your feet is limited) and to control.

This is a waveboard thread. your argumentation is flawed, or do you see F1 Cars at the Rally Dakar. Width main reason is not the Lift/Drag coefficent which your argument is, but because to have a bigger lever for the bigger fin you put into your slalom board. Which lets the board fly higher of the water which in the end reduces drag. Nothing else matters that much. BTW or why do think the tail in the slalom board is so narrow looking from under the board compared to the top. It is only the surface that touches the water that matter. Or why are Speed boards long and narrow. If width would be of any importance, speed boards would look different for sure.
But hey the earth is flat.

Ola,

Can you make any comment about how to keep a larger board from riding very rough when there is some chop?
This is something I deal with a lot in the side/side-on sailing I do.

SchobiHH said..

Bouke-Witchcraft said..

SchobiHH said..

Bouke-Witchcraft said..
Physical laws tell us that width is more important than length. More efficient. Look at the wings of sail planes or windmills. But there are other important factors. If you make a shorter board with the same total amount of rocker, it will have more curvature, thus drag more when getting planing. OTOH, for wave sailing, a longer board needs more total amount of rocker not to bury the nose and turn as well, so in fact have the same amount of curvature. Another really important and often overlooked factor is foot strap placement to adjust the trim angle. It has become fashion to place the straps quite far to the back. Moving the straps forward makes a big change to early planing, even more so for less skilled riders who are not as good in using mast foot pressure to keep the trim angle low. (BTW, for very big or tall riders often the boom cut out is (too) low, moving the boom up also helps to give MFP) By moving the straps forward you are increasing the planing area and especially the tail area. But in float n ride DTL riding there is hardly any sail pressure to convert into MFP so there it is also a good thing for skilled riders, given that the board has enough rocker to turn well. Or if you find the board slow and dull, moving the straps back just one position can totally change the board, make it faster and looser. Its happened various times that I gave such advice to customers and then hearing: I should have known that years ago.

"Physical laws tell us"? What do you know about physical laws? Everything I read from you doesn't make my believe that you have any.

Question: Why are airplane, windturbine or sail plane wings long (perpendicular to the flow=width with boards) and narrow (with the flow=length with boards)? I guess they are all developed wrong than eh? Why didn?t they listen to you? And we can go on to Formula boards, foils etc. etc.

If you would know something about physics than you would know the answer. But you have no shame to talk about physics... Simply tell me the governing physical law which backs your statement.

He can't tell you as he doesn't know, I think he is just regurgitating heresay. You can't have a logical factual discussion with someone like this. He's too dogmatic. It's like questioning religion with a religious person who's thoughts are based on "Faith"
But good on you for challenging his statements, as his replies then show everyone his flaws.

Ola H said..

Grantmac said..
Ola,

Can you make any comment about how to keep a larger board from riding very rough when there is some chop?
This is something I deal with a lot in the side/side-on sailing I do.

I assume you mean on the wave. But can you say a littel more about the type of chop. Is it still light winds but lumpy groundswell where you still get a kind of high riding speed. Or something else?

It's gusty 5-6m conditions (I'm 95kg) where you need a bigger board to get through the lulls but it's either choppy windswell or cross chop on groundswell if that makes sense? Probably a place where a FSW makes more sense than a pure waveboard.
I have in the past used a windSUP on the lighter days and I may do that again.

Gestalt said..
V to counter chop.

Here is my float and ride board. 232x68 135lt. Foam and 2.5 layers volan. No sandwich.

in my experience longer boards aren't as much fun once planing on a wave because swing weight slows the top turn down. You can't really see it in the photo but there was a lot of effort put into rail and bottom shape. Outline is pretty much inline with ola comments and again is what it is because of how it functions. So every element of the board was chosen to produce a specific outcome.
i tried to simplify the design into a purely functional response to the issues faced in light wind. Sounds wanky but is an approach I'm comfortable with.

Thoughts on the Exocet approach of the step tail? Absolutely not radical but definitely reduces swing weight.