quad question?
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Eric Carson
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At the Hatteras gathering last Fall, Andy Bezanilla brought his Blast round pin and his Friar Tucks, both quads. He related to me that his Blast worked better in steeper waves than the Friar tuck. He mentioned that the FT worked better in "Round waves".
Andy doesn't post often, but his opinion is valued to me, especially after seeing him surf. Check out his sequence shots from the gathering.
Andy doesn't post often, but his opinion is valued to me, especially after seeing him surf. Check out his sequence shots from the gathering.
Stemple,
I posted some stuff to the contrary on this thread viewtopic.php?t=445&postdays=0&postorder=asc&start=45
I think fins are given too much credit. Even looking at the pics you posted (nice boards, by the way), you can see big difference in the plane shape. I suspect the rails have their differences, too).
The fins are placed where they need to be in order to let the rest of the board work. Sometimes the algorithm that the shaper works for a particular board, sometimes a bit of fiddling is necessary, but I think the big changes come from the different tail widths at the fins and rocker/surface interactions (I include rail shape with rocker, since rails are an extension of the rocker curve)
That's not to say that fins are not important - you are right, they are vital. I believe that fins provide lift at 90 degrees to the rocker/bottom (or whatever the fin camber is), owing to their foiling. When trimming this "lift" "pushes" the fins towards the stringer (drag). This "lift" is also what pulls the tail of the board into the water when the board is on edge. It's possible to change characteristics of a board completely merely by altering fin foil. I know this is true on my thrusters.
Getting the zillion of things that make up a board to work together is what good shapers do. They have absorbed a ton of information into an intuitive picture far beyond what we can parametrise or put into computer models. That's why I've always tried to find a shaper who is good at his craft, open to discussion and constantly developing. I love Hart's idea that waterflow must be considered over the entire board surface - hence his boards travel as fast under the water as above it - really advantageous when you've overcooked it or really want to bury a rail.
Jack,
Sensational pic of the bro - extreme body positioning.
Notice how the outside fins are disrupting water flow off the side of the board (and forward), rather than out the back. Do you think this comes from the quad design or lack of fin toe-in? Maybe this also explains some of Steenos fan vs jet of spray ideas?
I posted some stuff to the contrary on this thread viewtopic.php?t=445&postdays=0&postorder=asc&start=45
I think fins are given too much credit. Even looking at the pics you posted (nice boards, by the way), you can see big difference in the plane shape. I suspect the rails have their differences, too).
The fins are placed where they need to be in order to let the rest of the board work. Sometimes the algorithm that the shaper works for a particular board, sometimes a bit of fiddling is necessary, but I think the big changes come from the different tail widths at the fins and rocker/surface interactions (I include rail shape with rocker, since rails are an extension of the rocker curve)
That's not to say that fins are not important - you are right, they are vital. I believe that fins provide lift at 90 degrees to the rocker/bottom (or whatever the fin camber is), owing to their foiling. When trimming this "lift" "pushes" the fins towards the stringer (drag). This "lift" is also what pulls the tail of the board into the water when the board is on edge. It's possible to change characteristics of a board completely merely by altering fin foil. I know this is true on my thrusters.
Getting the zillion of things that make up a board to work together is what good shapers do. They have absorbed a ton of information into an intuitive picture far beyond what we can parametrise or put into computer models. That's why I've always tried to find a shaper who is good at his craft, open to discussion and constantly developing. I love Hart's idea that waterflow must be considered over the entire board surface - hence his boards travel as fast under the water as above it - really advantageous when you've overcooked it or really want to bury a rail.
Jack,
Sensational pic of the bro - extreme body positioning.
Notice how the outside fins are disrupting water flow off the side of the board (and forward), rather than out the back. Do you think this comes from the quad design or lack of fin toe-in? Maybe this also explains some of Steenos fan vs jet of spray ideas?
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stemple
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Red,
I guess I would agree with you about fins (shape) not being that big of a deal. I can only really tell the difference in fins when I significantly change the size (length and base width). I have experimented alittle with fin rake etc without some of the results I have heard on this site. Some folks seem to be really into fin shapes and their effects. I probably have not surfed enough to know better.
I agree with you its about the board as a whole that must work together fins, rail lines, foils etc. I just hoping it was simple enough to break down into individual components.
If you envision the fins as foils or wings. Like any other wing they generate lift by water flowing faster over one side then other. A quad fin with two rail fins, like in the photo Jack posted, seems would create more lift along that submerged rail just by virtue of added wing or fin area. Is this additional lift also creating a bit of acceleration thus causing the tail to submerge kinda like a car speeding from a stop? Is this extra lift helping drive the board through the turn or help lift the rail out of the water? Does the toe-in of the fins "i.e.creating drag" compensate for the lift and acceration factor of additional fin area thus helping more of the rail stay submerged through the turn?
I think a couple more hits and it will all be clear
I guess I would agree with you about fins (shape) not being that big of a deal. I can only really tell the difference in fins when I significantly change the size (length and base width). I have experimented alittle with fin rake etc without some of the results I have heard on this site. Some folks seem to be really into fin shapes and their effects. I probably have not surfed enough to know better.
I agree with you its about the board as a whole that must work together fins, rail lines, foils etc. I just hoping it was simple enough to break down into individual components.
If you envision the fins as foils or wings. Like any other wing they generate lift by water flowing faster over one side then other. A quad fin with two rail fins, like in the photo Jack posted, seems would create more lift along that submerged rail just by virtue of added wing or fin area. Is this additional lift also creating a bit of acceleration thus causing the tail to submerge kinda like a car speeding from a stop? Is this extra lift helping drive the board through the turn or help lift the rail out of the water? Does the toe-in of the fins "i.e.creating drag" compensate for the lift and acceration factor of additional fin area thus helping more of the rail stay submerged through the turn?
I think a couple more hits and it will all be clear
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DrStrange
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Fins have critical effect differences at certain size/shape changes. Don't know exactly how this works with 3 or 4 but when boxes first came out, I experimented quite a bit with cutting/reshaping fins and found that I could cut and cut and feel no difference and then at one critical point 1/16-1/8 shaved off the trail edge or off the tip made a HUGE difference. Maybe multiple fins moderates this to a more gradual change effect but with one, it was very dramatic at one critical size difference.
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Steeno
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Hi stemple
My point of view only
I reckon the reason the you can throw the blast a little harder into a big carve is the fin placement and rail line, if you look at the two boards laying next to each other, the blast does have more tail area and with the back fins being that little further back than the parkes it is the compensation needed for that tail width, if the tail was narrower, you could place a third normal size fin at the same setting as the blast back fins-instead, to achieve a very similar feeling board in decent waves. But it would ride harder and deeper through a carve than the four because of the narrow tail in solid surf only, would be more a specialty board than an allrounder then.
On Daves board, with the back fins closer to the twin setup, should be alot looser than the blast and turn flatter, with Daves compensation only a slight detail of the swallow tail for a little more bite through turns.
As Beeline pointed out, these two are really apples V's oranges
line up the back fins not the twins to see the length of tail trailing behind them. The parkes has alot more length in tail from the trailing fins than the blast. completely different boards. would love to have a go on one of buds boards as a reference.
I know everyone cant have a quiver of boards for all surf conditions, and ideally it would be awesome to have an all round board to suit all conditions but I dont believe that is possible, to many variants in waves shapes and power. Buds board also has straighter lines with the step in the rail to pull the tail in a little plus tail lift, where as daves has a longer curve line, making it turn tightly in small waves-with no tail lift to help, and as you said a little more finesse is needed to get it on its rail-I would imagine more so in solid waves. As you also said buds has rocker in the tail and daves doesn't, this would be also to compensate somewhat for the straighter rail lines-in smaller punchy waves, Straighter rail lines to me means its easier to keep it on a rail in solid surf. to many variables to say these boards surf similar. Looks like buds board there is as close to an allrounder as possible. good post.
I reckon for myself that out of these two boards in 4ft sucky waves, on a carving re-entry Buds board would throw more spray because you need to carve it off the rail tail, not nurse through the carve, again, different boards for different waves.
just my thought
oh I forgot to say, keep this thread going, it went a bit of track from where we started but its all good.
My point of view only
I reckon the reason the you can throw the blast a little harder into a big carve is the fin placement and rail line, if you look at the two boards laying next to each other, the blast does have more tail area and with the back fins being that little further back than the parkes it is the compensation needed for that tail width, if the tail was narrower, you could place a third normal size fin at the same setting as the blast back fins-instead, to achieve a very similar feeling board in decent waves. But it would ride harder and deeper through a carve than the four because of the narrow tail in solid surf only, would be more a specialty board than an allrounder then.
On Daves board, with the back fins closer to the twin setup, should be alot looser than the blast and turn flatter, with Daves compensation only a slight detail of the swallow tail for a little more bite through turns.
As Beeline pointed out, these two are really apples V's oranges
line up the back fins not the twins to see the length of tail trailing behind them. The parkes has alot more length in tail from the trailing fins than the blast. completely different boards. would love to have a go on one of buds boards as a reference.
I know everyone cant have a quiver of boards for all surf conditions, and ideally it would be awesome to have an all round board to suit all conditions but I dont believe that is possible, to many variants in waves shapes and power. Buds board also has straighter lines with the step in the rail to pull the tail in a little plus tail lift, where as daves has a longer curve line, making it turn tightly in small waves-with no tail lift to help, and as you said a little more finesse is needed to get it on its rail-I would imagine more so in solid waves. As you also said buds has rocker in the tail and daves doesn't, this would be also to compensate somewhat for the straighter rail lines-in smaller punchy waves, Straighter rail lines to me means its easier to keep it on a rail in solid surf. to many variables to say these boards surf similar. Looks like buds board there is as close to an allrounder as possible. good post.
I reckon for myself that out of these two boards in 4ft sucky waves, on a carving re-entry Buds board would throw more spray because you need to carve it off the rail tail, not nurse through the carve, again, different boards for different waves.
just my thought
oh I forgot to say, keep this thread going, it went a bit of track from where we started but its all good.
Yep. Just remember that the lift is towards the curved side, so the "lift" when the fin is on its side in a turn is actually down INTO the water. (So I had it wrong before - in trim the fins "pull away" from the stringer, not towards it)Like any other wing they generate lift by water flowing faster over one side then other. A quad fin with two rail fins, like in the photo Jack posted, seems would create more lift along that submerged rail just by virtue of added wing or fin area. Is this additional lift also creating a bit of acceleration thus causing the tail to submerge kinda like a car speeding from a stop? Is this extra lift helping drive the board through the turn or help lift the rail out of the water?
If the fins don't pull the tail under water during a rail turn, the tail skips out. That's why I think it's more about correct foiling and shape than fin size. With a quad, speed-up effects between the 2 fins comes into play, but that starts to get all too complicated for me.
But the only way we can progress is to think about and discuss these things, come up with some ideas and see whether they fit what we observe in the water. I've learnt heaps from this and other "technical" threads.
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Beeline2.0
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hart
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Fins?
How could I not comment now?..coz I've been listening quietly.
Thanks the Beeline..
But, I hate fins.
I hate the way they dictate what your board does..and how some guys use them to make something in your board work.
Fins should be seen and not heard..(almost literally).
I want to feel the positive effect of fins (read, no slip) but not feel their negative effect (read, drag..water push..make you turn harder just to compensate for their area..) the list can go on.
The fin(s) should be as intrinsic to the shape as a rail..or bottom or outline. Like we wouldn't tollerate a bottom that 'pushed water'..or would we?
Why do Kneeboarders constantly refer to the incremental adjustment that finboxes acheive?..because we know how important each millimetre is.
Too far back..too hard.
Too far forward and is all too easy because we slide and lose control.
We are not like standups in this regard because we have a static prone position.
It all has to be as good as we can do it..we usually only get one chance..and as a Shaper, I know that I only ever do..once,
Crawford once said that when his (single) fin was put on a rail that the rail compensated by acting as a fin..I figure that was 1974..like 30 years ago..what have we now learnt?
Thanks to Red for really summing up what I believe most accurately..nothing is out there on it's own.
If your outline is too straight, with too much area through the tail, we will need more fin to control it. This will make us push harder. This may be good, but it may be not. If our fins are too far forward, we will need more straight through our tail..and a straighter bottom to control that. This may also be good..but similarly, may not.
To my point..
Let the fin(s) control your takeoff until you can sink a rail..once you do, let the curve in your rocker bring you off the bottom, naturally..and with speed. Allow the curve in your outline to then bring you off the top..if things are too straight..you WILL stick..or two stage..and either is fu#@ed.
Let the shape of your rails provide release out of the lip and the deck line of your nose provide a safe (uncatchy) arrival..at the bottom.
And then start the deal all over again.
Oh, and fins?..they were only mentioned once..a long time ago.
Regards again, from me.
Thanks the Beeline..
But, I hate fins.
I hate the way they dictate what your board does..and how some guys use them to make something in your board work.
Fins should be seen and not heard..(almost literally).
I want to feel the positive effect of fins (read, no slip) but not feel their negative effect (read, drag..water push..make you turn harder just to compensate for their area..) the list can go on.
The fin(s) should be as intrinsic to the shape as a rail..or bottom or outline. Like we wouldn't tollerate a bottom that 'pushed water'..or would we?
Why do Kneeboarders constantly refer to the incremental adjustment that finboxes acheive?..because we know how important each millimetre is.
Too far back..too hard.
Too far forward and is all too easy because we slide and lose control.
We are not like standups in this regard because we have a static prone position.
It all has to be as good as we can do it..we usually only get one chance..and as a Shaper, I know that I only ever do..once,
Crawford once said that when his (single) fin was put on a rail that the rail compensated by acting as a fin..I figure that was 1974..like 30 years ago..what have we now learnt?
Thanks to Red for really summing up what I believe most accurately..nothing is out there on it's own.
If your outline is too straight, with too much area through the tail, we will need more fin to control it. This will make us push harder. This may be good, but it may be not. If our fins are too far forward, we will need more straight through our tail..and a straighter bottom to control that. This may also be good..but similarly, may not.
To my point..
Let the fin(s) control your takeoff until you can sink a rail..once you do, let the curve in your rocker bring you off the bottom, naturally..and with speed. Allow the curve in your outline to then bring you off the top..if things are too straight..you WILL stick..or two stage..and either is fu#@ed.
Let the shape of your rails provide release out of the lip and the deck line of your nose provide a safe (uncatchy) arrival..at the bottom.
And then start the deal all over again.
Oh, and fins?..they were only mentioned once..a long time ago.
Regards again, from me.
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Jack Beresford
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finspins
Red - I have to plead total ignorance and have no idea why/how the water is channeling off my brothers board in that pic. It does look like the forward and aft fins are working as one.
Hart - I respectfully disagree with the statement that Kneeboarders are "prone" in one spot on their board. While we certainly don't move around as much as a standup, we do move our knees around - which has a critical impact on performance.
Hart - I respectfully disagree with the statement that Kneeboarders are "prone" in one spot on their board. While we certainly don't move around as much as a standup, we do move our knees around - which has a critical impact on performance.
Jack Beresford
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hart
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Prone position
Hi Jack,
Thanks for your comment.
I guess we can generalise and say that OZ boards are longer and have more curve than US shapes..(?)
In my opinion this means that we have much more of a critical sweet spot (due to bottom curve) than something straighter..oh yeah..and Thrusters are more critical again than a Quad..you gotta be in the right spot.
On all Farrer's boards we put a full foam deck pad..for his knees and feet.
I then have the statistics of his physical proportion between his knee bumps and the tops of both feet. And in actual fact, I am trying to develop grip that is based on a plaster cast that I have taken of the knee-shin-foot shape so that a fully moulded shape can be produced. I'm coming unstuck with flipper shape but..coz it works best for bare feet.
But back to Farrer..I then grind the entire pad of foam and contour it to take his prone position..designed for the same spot, each time.
So with foam that is one inch thick..in every place other than his knee, foot and shin position, it becomes almost impossible (or at least undesirable) to surf in any spot other than the one for which the board is designed..not to mention the individual for whom the board is Shaped.
Oh, and Red was talking about the water breaking of the outside fins..not the inside. And what a great Pic!..I love the committment the Surfer is showing to the turn in his body positioning..hot s#*t.
Hope it's all good.
PS
I in fact, also shape each board around the position of the surfer..so that I get bottom entry under the centre of weight, each and every time. Again, they're all Thrusters so this could attribute to the differences you are observing.
Thanks for your comment.
I guess we can generalise and say that OZ boards are longer and have more curve than US shapes..(?)
In my opinion this means that we have much more of a critical sweet spot (due to bottom curve) than something straighter..oh yeah..and Thrusters are more critical again than a Quad..you gotta be in the right spot.
On all Farrer's boards we put a full foam deck pad..for his knees and feet.
I then have the statistics of his physical proportion between his knee bumps and the tops of both feet. And in actual fact, I am trying to develop grip that is based on a plaster cast that I have taken of the knee-shin-foot shape so that a fully moulded shape can be produced. I'm coming unstuck with flipper shape but..coz it works best for bare feet.
But back to Farrer..I then grind the entire pad of foam and contour it to take his prone position..designed for the same spot, each time.
So with foam that is one inch thick..in every place other than his knee, foot and shin position, it becomes almost impossible (or at least undesirable) to surf in any spot other than the one for which the board is designed..not to mention the individual for whom the board is Shaped.
Oh, and Red was talking about the water breaking of the outside fins..not the inside. And what a great Pic!..I love the committment the Surfer is showing to the turn in his body positioning..hot s#*t.
Hope it's all good.
PS
I in fact, also shape each board around the position of the surfer..so that I get bottom entry under the centre of weight, each and every time. Again, they're all Thrusters so this could attribute to the differences you are observing.
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Birdie
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And here' s the bottom (sunglasses ladies and gentlemen) with the boxes for the Speeedfins installed....
I will be putting the Carbon Fiber Speeedfins in.....
http://www.speeedfins.com
I will be putting the Carbon Fiber Speeedfins in.....
http://www.speeedfins.com
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hart
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Wearing sunglasses at night?
Hi Birdie,
I was going to say something about 'Blue and green should never be seen..unless there's something in .....' and then I remembered my beautiful Gran doesn't have the Internet
But, I gotta say that the closer your rail fins are to the rail (and you've got four of the buggers..and they are way out there..) that the less rail you will get in the water..like the fins won't let your rail sink.
It's all good..your newy looks like it will react positively off it's fins and go from one rail to the other..quickly..and then back again.
Let us know how it goes..and was that 3" of thickness?
Regards from sunny OZ.
I was going to say something about 'Blue and green should never be seen..unless there's something in .....' and then I remembered my beautiful Gran doesn't have the Internet
But, I gotta say that the closer your rail fins are to the rail (and you've got four of the buggers..and they are way out there..) that the less rail you will get in the water..like the fins won't let your rail sink.
It's all good..your newy looks like it will react positively off it's fins and go from one rail to the other..quickly..and then back again.
Let us know how it goes..and was that 3" of thickness?
Regards from sunny OZ.