Standup Zone Forum
The Foil Zone => Foil SUP => Topic started by: liv2surf on April 17, 2020, 10:21:17 PM
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I am a very new SUP foiler who has been SUP surfing for 4y and kite foiling for ~5y. When standing on the board in surf I have noticed a weird foil sensation that I wanted help ‘interpreting’. When I am standing on my 6’6” 125-135L SUP foil board with foil tracks with a big 1720 cm^2 foil on a thin 28” aluminum mast, I feel a wobbling or vibration/oscillation of the foil underneath me. I am guessing this is a well known phenomenon. It is a bit disconcerting. Is this most likely the foil boxes and the bottom skin flexing or the mast itself bending? (I did search for this subject but did not find results that answered my question). If this is the boxes and bottom skin flexing, is this board likely to blew out the foil boxes?
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likely the mast flexing. Big wing and not very stiff mast is very noticeable in exactly this way when standing on the board
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You can probably figure this out on land by pushing on foil and seeing where the movement is.
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It’s the mast flexing. It’s why all our local crew ride Axis. It is the stiffest mast on the market. Once you ride a stiff mast, you immediately figure this out, by going back to your old setup for a comparison. I’ve felt mast wobble so bad, the vibration came through the deck into my feet.
Also be sure to shim and hammer your base plate onto the mast. This continues to be a design weakness in all brands, including Axis. It’s a product of the aluminum extrusion, where the extrusion dies wear with age, causing the masts to change thickness. So it’s never going to go away as an issue, until someone smart, designs a better mast to base plate system.
It’s a crying shame so many brands continue to offer masts too flexible for SUP surfers.
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Thanks for the replies. Yes, I had seen the thread where people were discussing that Axis is a SUP favorite due to stiffness. It is interesting that my aluminium mast (Cloud IX) would flex/wobble more than the boxes and board bottom. I guess if boxes flex you get cracks followed by failure so this is probably correct. I agree that I should be able to convince myself of which mode of wobble is occurring by applying force to front wing with foil up (out of water) and watching where I see motion.
See my post about new video about new Armstrong Wing Foil SUPS and their use of 2 carbon parabolic stringers encasing the foil boxes:
https://www.standupzone.com/forum/index.php/topic,35269.msg414219.html#msg414219
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I did not like the wobble of the Cloud IX 28" aluminium mast on my SUP.
I am planning to buy a new foil for SUP and wing SUP. I am deciding between Armstrong with 72cm carbon mast and Axis with 68 or 75 cm aluminium or 76 cm carbon mast.
Will the Armstrong and Axis carbon masts have too much wobble (like the Cloud IX)? Will the thicker Axis mast (19mm, I believe) be the only one with sufficient stiffness for SUP?
You comments are appreciated.
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Will the Armstrong and Axis carbon masts have too much wobble (like the Cloud IX)? Will the thicker Axis mast (19mm, I believe) be the only one with sufficient stiffness for SUP?
My buddy rode the Axis carbon. He said forget about it. Too much flex and twist. He’s staying on aluminum.
Army Armstrong says mast flex is a design feature. So forget about it.
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On my armstrong in the surf and in the choppy conditions I have never noticed this wobble feeling you are dealing with. I have 72cm armstrong mast.
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Some masts, while not feeling a direct wobble, do make a SUP feel less stable. You really have to ride a super stiff mast long enough to know it well, then try something less stiff, and it’s a big time hell no.
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My guess is stiffest carbon mast out there is LP in Hood River. It has zero flex but on heavier side. Peter will make one any length you want. He also has a wide selection of high aspect foils.
I heard an interview of the guy who started Axis and was impressed to with commitment to making a stiff mast.(the bigger Al one).
Haven't read a lot of complaints about Armstrong. Armie claims the location of flex matters and that his masts are tapered and flex at the bottom and not the top.
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Less flex also lets you paddle is harsher conditions. I was tapping out in about 12 knot winds with the Neil Pryde, now I can stay paddling in over 20 knots with the Axis. My local kiters liked it better when I couldn't keep on the waves in the higher winds.
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totally agreed with DW - hell no on mast flex. It has always puzzled me that armstrong touts it as a feature. The difference going from the old gofoil mast to the new wider/stiffer one is like night and day and I would never go back. I say the stiffer the better.
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Thanks for everyone's comments here. Obviously, there is a bit of difference of opinion here, though the consensus is stiffer is better for SUP. NI agree Army thinks flex is a design element and flex at bottom is more acceptable... but I suspect he is coming more from a kite and/or prone foil background (where you don't need the stiffness for stability to stay out there as needed on SUP).
One point of clarification. Axis has two mast thicknesses, the 16mm and the 19mm. Are comments about stiff Axis mast specific to the 19mm masts?
So, advocates of stiff masts for SUP foiling believe that the benefits of stiffness out weighs the disadvantages of weight?
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I have ridden these foils enough to know I do not feel them flex or vibrate . I have especially dug them hard in terms of turns and stresses behind the boat at higher speeds. I have had out in the surf in up to head high, and did not feel any wobble or vibration. And his masts are wood core with the carbon fiber so they are not going to act like the pure carbon masts out there. One of the reasons I went with the armstrong foils.
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19mm mast. 5oz lighter in carbon and less stiff. When carbon matches that 19mm aluminum mast, it‘s heavier. Axis did the thicker at the top carbon trick too.
CloudIX released a carbon mast and it was heavy. They told me at surf Epoxy they just made one because some people wanted one, regardless....
Lots of people keep trying.
I’m curious about Slinghot’s new trick carbon mast coming. Dealer materials were send out months ago. Still haven’t seen the public release. They claim to have the stiffest carbon mast ever made. Going by memory, so don’t quote me.
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I take my 72CM and 85CM Armstrong Mast w/ giant 2400cm wing out winging in my local spot that has a stretch with 1-2' windswell chop running into the river shoreline bulkhead then rebounding back out. A complete mess.
I do not notice any negative 'flexing' from the Armstrong Mast. I can stand on DW's small board when off foil without much issue.
I think Armstrong's 'reactive' flex is something that more experienced riders enjoy, similar to a snowboard with strong camber and good sidecut. Not great for a beginner trying to go straight, as they can't drive the snowboard yet. The board can get kicked around without rider input and a beginner might fault the board.
While I do think I may feel a small amount of movement of the wing, It is nothing like a uniform aluminum mast flex. At one point back in the day I ordered a carbon fiber mast from some Ukrainian startup to replace my Cloud IX aluminum mast. Now that was a complete noodle! It was so loose it failed the first session!
Comparing Armstrong's mast to a thin aluminum mast is like comparing a cheap pair of plastic FCS fins to the premium blackstix with sophisticated flex pattern. Both flex, but not at all equally.
I would love to hear input from an experienced rider who's been on both Axis and Armstrong for input.
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I would love to hear input from an experienced rider who's been on both Axis and Armstrong for input.
totally agreed - sounds like people are fine with Armstrong's mast, but have they ridden a 19mm axis aluminum? Before I had a stiff mast, I didn't think much of the mast I had. Once I did, I couldn't go back.
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My experience is that wobble or high frequency movement / flex is often something loose, like bolts not tight enough, and it sucks/hard to control. I've also felt wobble when the tracks were failing or had failed.
I'm surprised to hear people say they like a really stiff mast, I much prefer some flex. The way I make sense of this is like bird wings and fish fins all move or flex.
I have tried carbon masts that are much stiffer than the original gofoil and I prefer a well made aluminum mast.
Reminds of Surftech boards that were super stiff and dead feeling, they would skip out or wouldn't bend to match the curves in the wave face.
I understand the precision direction control that comes from a stiff mast, I prefer a mast that moves and goes with the flow of the wave energy.
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My progression has been:
1. Old GoFoil 24" mast--felt fine, all these problems are just me.
2. GoFoil 29" mast. OMG, this is so much better. Maybe some of those problems were the mast. No worries, I'm not going back. I am a golden god of foiling.
3. Axis without shimming. Wow, this is great. Still having some issues, but they must be me. I am a silver god of foil.
4. Axis with shimming. Wow, so much better. All these issues are me. I am a kook of foiling.
Conclusion--the better your gear is, the more you suck.
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My buddy rode the Axis carbon. He said forget about it. Too much flex and twist. He’s staying on aluminum.
I can't comment for SUP but for winging we are really happy with the Axis 760 carbon masts. There is a noticeable drag reduction. It is an incredible feeling. I am not sensing any additional flex or twist but if it is there it is very pleasant :).
One thing that will be an issue (and is easily overlooked) is the offset. The carbon mast moves the foil assembly back considerably. It is not readily apparent just from eyeballing it. If you use your screw position for matching to your track marks the foils will be moved back by just over an inch. If you use the front of the plate for matching to your track marks the foils will be moved back by over an inch and quarter. So you will have to adjust the mast forward to get the same foil position. If you don't catch that it can make for a very funky session, especially if you have your straps just where you like them :).
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Naish have a wider, stiffer and lighter mast coming soon.
I have put an order in for the 85.
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You can probably figure this out on land by pushing on foil and seeing where the movement is.
Good suggestion. This was easy with board deck down, foil up, me pulling on the wings. The mast flex was super obvious. I was stunned by this. No bueno.
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My buddy rode the Axis carbon. He said forget about it. Too much flex and twist. He’s staying on aluminum.
I can't comment for SUP but for winging we are really happy with the Axis 760 carbon masts. There is a noticeable drag reduction. It is an incredible feeling. I am not sensing any additional flex or twist but if it is there it is very pleasant :).
One thing that will be an issue (and is easily overlooked) is the offset. The carbon mast moves the foil assembly back considerably. It is not readily apparent just from eyeballing it. If you use your screw position for matching to your track marks the foils will be moved back by just over an inch. If you use the front of the plate for matching to your track marks the foils will be moved back by over an inch and quarter. So you will have to adjust the mast forward to get the same foil position. If you don't catch that it can make for a very funky session, especially if you have your straps just where you like them :).
Is the aluminum mast square on the ends? I’ve seen some not square. By that much.
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Hi Dwight,
Yup, they are square. I added the vertical lines to this Axis photo to show what I mean. The lines are from the screw holes on each of the 3 plates. It is no problem to adjust for this offset once you know that it is there but it did throw me a bit when I put my straps back on. It is over 1.25 inches offset difference between our aluminium and carbon setups.
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I added the vertical lines to this Axis photo to show what I mean. The lines are from the screw holes on each of the 3 plates. It is no problem to adjust for this offset once you know that it is there but it did throw me a bit when I put my straps back on. It is over 1.25 inches offset difference between our aluminium and carbon setups.
Unfortunately it can be a problem , when the waves are slow and small I have to put my Axis alu mast all the way in front in the tracks of my Jimmy Lewis Flying V 5'11 I use a front foot strap and it took me some time to find the right mast and footstrap position...
On my custom 6'6 I have my mast all the way in the back of the tracks, and I have the feeling it is still to much forward, the board doesn't paddle as straight as I would like and I cannot move the front foot strap more to the front because I tend to push the nose of the board underwater when I try to catch a wave.
The Axis plate has extra holes and I am planning to use them, I already made them a little bigger so that M8 will fit.
I will get my 76 cm carbon mast next week, when I look at your photo Admin it won't be possible to move it as much to the front as an alu mast but perhaps it will be possible to move it even further back than the alu mast....
But there might be some distortion in this photo....,
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I added the vertical lines to this Axis photo to show what I mean. The lines are from the screw holes on each of the 3 plates. It is no problem to adjust for this offset once you know that it is there but it did throw me a bit when I put my straps back on. It is over 1.25 inches offset difference between our aluminium and carbon setups.
Unfortunately it can be a problem , when the waves are slow and small I have to put my Axis alu mast all the way in front in the tracks of my Jimmy Lewis Flying V 5'11 I use a front foot strap and it took me some time to find the right mast and footstrap position...
On my custom 6'6 I have my mast all the way in the back of the tracks, and I have the feeling it is still to much forward, the board doesn't paddle as straight as I would like and I cannot move the front foot strap more to the front because I tend to push the nose of the board underwater when I try to catch a wave.
The Axis plate has extra holes and I am planning to use them, I already made them a little bigger so that M8 will fit.
I will get my 76 cm carbon mast next week, when I look at your photo Admin it won't be possible to move it as much to the front as an alu mast but perhaps it will be possible to move it even further back than the alu mast....
But there might be some distortion in this photo....,
Hi Soekip,
I think you have it right. If you are maxed out forward in the tracks with the aluminum mast then your fuselage is going to be set a little over an inch back of there with the carbon mast. On the upside, you will gain that same measurement at the back of tracks.