The Phantasm carbon 103W is super-stiff but is it bending?
GoPro SuperView perspective?

Try to ignore the 3/4 wetsuit legs

All materials "move", just a question of how much. Ii suspect that visual is more lens distortion though. The single piece desigh of the W103 (huge foot, large radius fillet at the foot to mast interface, and variable cord length), certainly could be the most rigid design possible.
Beyond the design though, it's all about the execution . "Proof is in the pudding" . I've only ridden the aluminum 90cm hoverglide and W103.
Huge difference for me.

Interesting pictures!

There may be some distortion from the wide angle lens, but the mast is definitely bending quite a bit. I read an interview from top foil racers/developers where they stated that they have gone away from mast longer than 95 cm, even though they offer advantages in chop, due to stiffness issues. But in your pictures, there seems to be quite a bit of bending close to the board (I measured ~ 10 degrees, vs. 15 degrees further down).

I wonder how much the top plate mount adds to the bending. Mechanically, the right-angle connection at the top could easily be the weakest point, since you do not have any straight carbon fibers aligned with the direction of the bending force.

Yes they do bend, sometimes visibly. I think the bottom pic is an exaggeration of both lens distortion and probably the camera not being able to catch a quickly moving image. What was the frame rate you were using?

The effect can be really bad on things like propellers.

I don't think the angle between the board and the top of the mast looks right though, so probably just lens distortion making them not look 90deg.

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WsurfAustin said..
All materials "move", just a question of how much. Ii suspect that visual is more lens distortion though.

Check out the section near the bottom of the board with the image straightened out so the board is horizontal:

The observed angle can NOT be explained with lens distortion.

Should be easy to verify on land by putting the board on its side and a kettle bell or two at the end of the mast.

Yes, they bend.

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segler said..
Yes, they bend.

I wonder if the bending can even be beneficial? For example, a bit of give could dampen some sudden load changes, both from gusts etc. above the water, and from turbulence in the water. Intuitively, I would think that carbon has better bending and rebound characteristics than aluminum, although I have no clue if that is really so.

I'd say that's at least 50% lens distortion or else the W103 base plate is massively underbuilt.

I don't think my 103 W would bend like that my guess is that frame grab is from a go pro? Your going to have some distortion even with the newer ones

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boardsurfr said..
I wonder if the bending can even be beneficial? For example, a bit of give could dampen some sudden load changes, both from gusts etc. above the water, and from turbulence in the water. Intuitively, I would think that carbon has better bending and rebound characteristics than aluminum, although I have no clue if that is really so.

In my experience, no. Stiffer mast, both torsionally and laterally, allows a more controlled and faster ride. I've gone back and forth between SB Race 95 carbon (1st gen) and a custom mast (stiffer than C600), same wings, same board. So far I haven't found a scenario where I'd prefer a softer-flexible mast.

You can look at the moments, (torques) about the longitudinal axis of the board. (There isn't too much moment of inertia around that axis, it's not hard to flip the bare board over before putting it on the roof rack). If the moments are too much out of balance it will spin up about that longitudinal axis pretty quickly.

So you've got the mast, judging by its bend, wanting to rotate the board clockwise, the universal joint, judging by its bend - anticlockwise. Any pressure from the right foot is clockwise. All to be balanced by JJ's mighty left foot pressure only 6 inches out from the centre line?

Don't think so. It's distortion added by the GoPro Superview perspective. If you stand up and view your screen looking down at 45 degrees you can add a whole lot more distortion.

In Segler's shot the torque applied anticlockwise is balanced by the full rider's weight right out on the rails. Plus the bend is nice and smooth, not all concentrated at the box.

All materials deflect under load. Obviously stiffer materials deflect less for the same load.

Having said that, I think the photo is an optical allusion. The camera angle is not at 90 degrees to the back of the board, its view is slightly offset to the right. Also, the mast appears to be bending the wrong way. JJ loading up his heals as he banks a turn to the right. Under these loads, wouldn't you expect the mast to bend the other way?

Yes, absolutely they bend.

I think as others have said there's a certain amount of camera related distortion in the two pics, but I've foiled along behind Bastien before and watched his foil mast bend in a similar fashion to the first pic for real, quite close to the foil head. Bastien is a very talented sailor who tests his equipment to the extreme, and sadly the foil at a later date broke off on him with the break occurring at the location of the maximum flex. That's not to say flexing means imminent breakage though.

Have watched plenty of other foil masts flexing on a more natural curvature as well. I think most of the opinions I've heard on whether flexing masts are a good thing range from "no, but I can live with it" to an outright "no, not a good thing at all".

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Ian K said..
You can look at the moments, (torques) about the longitudinal axis of the board. (There isn't too much moment of inertia around that axis, it's not hard to flip the bare board over before putting it on the roof rack). If the moments are too much out of balance it will spin up about that longitudinal axis pretty quickly.

So you've got the mast, judging by its bend, wanting to rotate the board clockwise, the universal joint, judging by its bend - anticlockwise. Any pressure from the right foot is clockwise. All to be balanced by JJ's mighty left foot pressure only 6 inches out from the centre line?

Don't think so. It's distortion added by the GoPro Superview perspective. If you stand up and view your screen looking down at 45 degrees you can add a whole lot more distortion.

In Segler's shot the torque applied anticlockwise is balanced by the full rider's weight right out on the rails. Plus the bend is nice and smooth, not all concentrated at the box.

I reckon you're spot on - SuperView lens distortion.

Look forward to seeing you back on the water when it warms up

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azymuth said..

Ian K said..
You can look at the moments, (torques) about the longitudinal axis of the board. (There isn't too much moment of inertia around that axis, it's not hard to flip the bare board over before putting it on the roof rack). If the moments are too much out of balance it will spin up about that longitudinal axis pretty quickly.

So you've got the mast, judging by its bend, wanting to rotate the board clockwise, the universal joint, judging by its bend - anticlockwise. Any pressure from the right foot is clockwise. All to be balanced by JJ's mighty left foot pressure only 6 inches out from the centre line?

Don't think so. It's distortion added by the GoPro Superview perspective. If you stand up and view your screen looking down at 45 degrees you can add a whole lot more distortion.

In Segler's shot the torque applied anticlockwise is balanced by the full rider's weight right out on the rails. Plus the bend is nice and smooth, not all concentrated at the box.

I reckon you're spot on - SuperView lens distortion.

Look forward to seeing you back on the water when it warms up

When it warms up Some of the joints squeek and groan as you get to the 8th decade. You did well to get out yesterday on the 2.8! I was overpowerd in a thick beanie. Blown off my feet in a gust at Sth Beach!

The GoPro lens did not distort the sail mast which is at a similar position relative to the GoPro, or the trailing edge of the sail below the boom, so I think the bend seen in the foil mast is real.

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boardsurfr said..

WsurfAustin said..
All materials "move", just a question of how much. Ii suspect that visual is more lens distortion though.

Check out the section near the bottom of the board with the image straightened out so the board is horizontal:

The observed angle can NOT be explained with lens distortion.

Should be easy to verify on land by putting the board on its side and a kettle bell or two at the end of the mast.

It would be easier to verify if you set the board at the same angle on dry land and take a screenshot from the video with the camera in the same position.

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PhilUK said..

boardsurfr said..

WsurfAustin said..
All materials "move", just a question of how much. Ii suspect that visual is more lens distortion though.

Check out the section near the bottom of the board with the image straightened out so the board is horizontal:

The observed angle can NOT be explained with lens distortion.

Should be easy to verify on land by putting the board on its side and a kettle bell or two at the end of the mast.

It would be easier to verify if you set the board at the same angle on dry land and take a screenshot from the video with the camera in the same position.

The sail mast and trailing edge of sail are internal controls for any lens distortion.

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Sandman1221 said..

PhilUK said..

boardsurfr said..

WsurfAustin said..
All materials "move", just a question of how much. Ii suspect that visual is more lens distortion though.

Check out the section near the bottom of the board with the image straightened out so the board is horizontal:

The observed angle can NOT be explained with lens distortion.

Should be easy to verify on land by putting the board on its side and a kettle bell or two at the end of the mast.

It would be easier to verify if you set the board at the same angle on dry land and take a screenshot from the video with the camera in the same position.

The sail mast and trailing edge of sail are internal controls for any lens distortion.

Not they aren't, they are at the top of the picture, using a different part of the lens. These go-pros are extreme wide angle lenses, I wouldnt assume that all parts of the lens are perfect or comparable. I dont know about gp-pro's software, but some digital cameras correct barrel distortion from using wide angle lenses on small sensor cameras. If anyone wants to take a video of a mast bending in use, I'd suggest framing the shot to put the mast in the centre of the picture to avoid barrel distortion.

ps, and image stabilization software can distort images as well.

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aeroegnr said..
Yes they do bend, sometimes visibly. I think the bottom pic is an exaggeration of both lens distortion and probably the camera not being able to catch a quickly moving image. What was the frame rate you were using?

The effect can be really bad on things like propellers.

I don't think the angle between the board and the top of the mast looks right though, so probably just lens distortion making them not look 90deg.

There is a LOT going on in that picture that doesn't apply to the mast bend topic. You mentioned frame rate, which is most of what is happening in your picture, but frame rate doesn't really have much affect on Azymuth's picture. Why? Because in Azymuth's picture nothing is really moving relative to the camera. It can largely be considered a static picture. Another thing that is happening in your picture is the way an individual frame is taken. (And again, this doesn't apply to Azymuth's picture.)

Way back in the day when the camera shutter was first being developed the engineers decided it made more sense for the shutter to close downwards so that it didn't have to fight gravity. That practice still continues today on mechanical shutters. (Incidentally, the shutter is in reality two shutters moving together. Once the exposure time exceeds a certain value what you really have is a moving slit of light exposing the film or CCD array.) On an electronic shutter such as a full frame mirror less there is an enormous amount of data being generated in a quick burst. It can't be transferred all at once so the engineers decided that they would stick to the old convention and gather it from the top to the bottom which is again the direction that the mechanical shutter moves. This is why if you look at a 1/400 speed picture of a golf swing at impact the shaft looks SO bowed forwards. Most of that is the effect I just talked about. Only a small amount is that the shaft really does bow.

Anyway, again, in the foil mast bend pictures we are seeing I agree that the lion's share is wide angle camera distortion. In fact, if you lay a piece of paper across the water on the horizon you see that IT is bowed as well. (Of course some of that could be the shoreline, can't tell.) But there is no doubt at the end of the day that the masts ARE bending some and maybe a lot. I've seen too many permanently bent aluminum masts to doubt it and has been pointed out, everything bends to some extent. (I know you know this.)

(Source? 33 years of engineering at Nikon.)

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BullroarerTook said..

aeroegnr said..
Yes they do bend, sometimes visibly. I think the bottom pic is an exaggeration of both lens distortion and probably the camera not being able to catch a quickly moving image. What was the frame rate you were using?

The effect can be really bad on things like propellers.

I don't think the angle between the board and the top of the mast looks right though, so probably just lens distortion making them not look 90deg.

There is a LOT going on in that picture that doesn't apply to the mast bend topic. You mentioned frame rate, which is most of what is happening in your picture, but frame rate doesn't really have much affect on Azymuth's picture. Why? Because in Azymuth's picture nothing is really moving relative to the camera. It can largely be considered a static picture. Another thing that is happening in your picture is the way an individual frame is taken. (And again, this doesn't apply to Azymuth's picture.)

Way back in the day when the camera shutter was first being developed the engineers decided it made more sense for the shutter to close downwards so that it didn't have to fight gravity. That practice still continues today on mechanical shutters. (Incidentally, the shutter is in reality two shutters moving together. Once the exposure time exceeds a certain value what you really have is a moving slit of light exposing the film or CCD array.) On an electronic shutter such as a full frame mirror less there is an enormous amount of data being generated in a quick burst. It can't be transferred all at once so the engineers decided that they would stick to the old convention and gather it from the top to the bottom which is again the direction that the mechanical shutter moves. This is why if you look at a 1/400 speed picture of a golf swing at impact the shaft looks SO bowed forwards. Most of that is the effect I just talked about. Only a small amount is that the shaft really does bow.

Anyway, again, in the foil mast bend pictures we are seeing I agree that the lion's share is wide angle camera distortion. In fact, if you lay a piece of paper across the water on the horizon you see that IT is bowed as well. (Of course some of that could be the shoreline, can't tell.) But there is no doubt at the end of the day that the masts ARE bending some and maybe a lot. I've seen too many permanently bent aluminum masts to doubt it and has been pointed out, everything bends to some extent. (I know you know this.)

(Source? 33 years of engineering at Nikon.)

Yup, bingo. Thank you for the thorough explanation. I was thinking the only way it would be that effect is if there was a lot of rotation of the whole thing or the camera in that particular frame. It's probably all lens. It's more of: be careful with video/pics because sometimes it's not what the observer thinks it is.

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BullroarerTook said..
I've seen too many permanently bent aluminum masts to doubt it and has been pointed out, everything bends to some extent.

Again, I wonder how much of the "carbon masts are better" comes from how a mast returns after being bent. Some of the stiffness numbers posted on this forum showed that some carbon masts bend more than aluminum masts. Looking at booms that also come in carbon and alu, I had plenty of bent alu booms, but never a bent carbon boom. Carbon either returns to the original shape, aluminum often does not.

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boardsurfr said..

BullroarerTook said..
I've seen too many permanently bent aluminum masts to doubt it and has been pointed out, everything bends to some extent.

Again, I wonder how much of the "carbon masts are better" comes from how a mast returns after being bent. Some of the stiffness numbers posted on this forum showed that some carbon masts bend more than aluminum masts. Looking at booms that also come in carbon and alu, I had plenty of bent alu booms, but never a bent carbon boom. Carbon either returns to the original shape, aluminum often does not.

I was skeptical of carbon foils a couple of years ago and it was true some brands aluminum masts were stiffer than their carbon mast however the slingshot phantasm mast and foil set up is significantly stiffer than the Hover glide aluminum mast and set up.

Having ridden the phantasm 72, 82 and 92cm masts for over a year now I don't need lab results or graphs and charts, it comes from hundreds of hours of real time foiling.

Think as many have said in this thread you will get a deflection in any material when its being loaded up and JJ carves extremely hard more so than most free-foilers, but I also think the camera lens is clearly adding to the distortion in the photo.

When Horue bought out their carbon foil to the masses in 2016 I would sail behind a local guy and the mast bend was very obvious like in Seglers pic.

The only thing not straight in those pictures, that are similar in distance from the camera, is the foil mast!