So I recently got a custom DW board, and fear that the tracks are too far back. I’m comfortable with my back foot directly over the mast, but with the mast all the way forward, if I stand like that the tail is in the water and the nose out, so not efficient through the water. If I stand where the board is level, I’m over the leading edge of the mast or just overlapping I think. I’ve caught waves at the beach already, but I have to pull it back to take off, and I feel like I’m 30/70 front/back. I can imagine not being able to properly pump/paddle fast with lift when it comes to catching bumps instead of waves. And as I’ve mentioned before maybe too many times, I have experience already with tracks too far forward hampering my prone journey, and I don’t want to make the same mistake again. Based on my description would folks with experience agree or not that I should be concerned, or is there a hack? Center of tracks 25.5” from tail on a 7’6” board.
Edit: mistake being trying to make it work when I should just get another board.
I’ve seen track extenders. I couldn’t tell you where to get them but they’re out there. Obviously it’s not the prettiest but could save you time and money making a new board.
This is who made a run of the aluminum track extenders. I don’t think he has anymore or plans to make anymore at the moment. You could message him on instagram though.
I’m thinking about moving them, depending on how the box was installed. I remember working at a boat builder in the 90s a French foiling catamaran broke a foil and brought it in for repair, one of the more experienced guys ground out a taper in maybe 15 layers of carbon 1” per layer. It was the most impressive thing I’d seen done with a grinder. So the repair was one layer proud. If I go after it with this board I’ll try to channel that performance.
I just whipped up these track extenders for my board. I used alu t-slot roof rack tracks harvested off a Sprinter van. Bolted them into tracks using same hardware and bolted foil onto washers in the t-slot in front. It took me 30 minutes to make these. They seem stiff enough for flatwater paddle up with axis 1300. Not sure how it would do in waves.
Can I ask why the foil needed to be further forward? When I study the Casey downwind videos I notice that all the guys have their back foot on the mast when control is required on foil bombing downwind. This seems to be the same across the brands represented in the videos, lift, gofoil, axis and uni with no more than 40mm difference. So it does make you wonder how the boxes don’t offer enough but maybe they were never in the right place for paddling up?
My take is that you want to have minimal foot movement between your paddling position and your flying position. If you need to move back as you take off then you have one more thing to upset the process.
Imagine the board having an optimal balance position for paddling. That is pretty fixed and the board will be difficult to paddle standing anywhere else. With the foil too far back you’ll have an entirely different balance point for the foil, and so as you transition you’ll need to shuffle backwards.
Watch first generation sup foil takeoffs in waves and you’ll see they need to walk 2-3 foot backwards during the takeoff to go from paddling position to foiling position.
This makes sense. One position for paddling because of one balance point.
But then if there is little difference between where the back foot is placed in comparison to the mast across the brands when flying then it tells me the boxes were in the wrong place regardless of the brand of foil.
I guess I hear lift and Armstrong are very back footed and other brands might be very front footed but when you look at the best riders for each of the brands they stand with their back foot on the mast with up to only 50mm difference from the very far back to the forward.
You would like to think if the boxes are placed in the correct position in relation to the balance point then there should be enough adjustment to cover the different brands.
Where the center of lift is with respect to the mast also varies some cm between brands, fuses within brands, and tail selection. So quite quickly we are talking 10cm of range, or a large cunk of a standard length track. Only need to be off a few cm in ideal track placement and some people run out of room, in spite of your astute observations.
The convergence on efficiency for DW, which is currently low lift on the stab and mast further forward (the armstrong and lift approach), is a relatively recent development and so the difference between brands is almost certainly less in this application than it was 18 months ago. Recent vids capture this as you note but conventional wisdom takes longer to catch up.
The mast isn’t placed on the same place on the board for different brands. So just because a rider’s foot is over the mast. That doesn’t tell you where the mast is in the box. GoFoil rides far back in the box. With their new mast/fuse the front wing is placed further forward away from the mast. So if you use an old GoFoil mast and the new GoFoil mast back to back. They would be put in different places in the box.
AXIS is also placed further back in the boxes in general. If you use an AXIS Ultrashort fuse and then put on an AXIS Advanced Ultrashort fuse. You’d have to move the mast forward in the boxes +40mm when using the Advanced Ultrashort fuse.
Lift ha120 rides all the way forward in my prone board tracks. When I use the lift ha90 which has the front foil further forward from the mast, I have to move the mast back a fingers width back from the front of my tracks.
Standing over the mast doesn’t really tell you much. If you’re not wearing straps you should be moving your feet all the time anyway.
Where the mast is in the box is irrelevant to my point once flying. My observation is that for best control at critical times all these guys have their back foot on the mast. We are talking dw here not prone. For prone it is an even more messed up discussion with even the best sliding forward on the jump up to compensate for the foil being so far forward and yet when flying again the back foot is on the mast for the best riders.
The talk of fuselage is a factor but so is tuning with the stab variabilities and still this results with the best still standing on the mast with only a little variation.
It seems that the lift profile of the brand is less important for rear foot placement than the best place to control the foil which seems to be over the mast. So maybe it will become important to match the lift profile with the need to stand on the mast, just a theory and maybe the best are doing this even if unconsciously at times. Maybe the lift profile is factoring more into the stance width. Lift narrow and gofoil more surf.
There seems to be a lot of confusion and misconceptions about where the boxes need to be and I guess is a result of the sport still and equipment evolving radically. I have asked one or two of these guys and they also seemed surprised by the little difference and even their own foot position.
The gofoil v2 mast is a case in point as some riders seem to have started downsizing tails to still stand on the mast which ultimately results in less drag and the foil moving back to almost the same position in the box as the previous mast.
But where the mast is in the box is super important. When it comes to downwind boards you need to balance them to get the best performance. Go ride a Kalama e3 downwind with Gofoil. Then put a lift 120 on it and you won’t be able to get it off the water.
Added in some photos so we could see what we’re looking at. I’ll also cut and paste off the Amos website.
During our research in building of Phantom SUP foil board it became apparent that we needed to include 16” tracks to allow the rider to interchange between different foil brands and wing sizes.
I understand all the theory of the correct place to stand on the board and yes it is irrespective of the foil brand and positioning.
But why when foiling are all these guys balancing the lift of the various brands by standing on the mast. It indicates all these brands could place their foils within 50mm on the same board as the lift is controlled well by all with back foot within 50mm when comparing to each brand.
Now to even complicate things further when halfway through a dw paddle up they are moving their back foot temporarily further forward, just like when preparing to pump off the back of a wave, which is contrary to your experience of needing the foil even further forward. If you don’t do this on the paddle up the foil seems to stall with aggressive aoa.
I don’t have all the answers but my observations suggest something is amiss. Like I said when I asked the question to a few of these guys prone conventions were playing into the positioning more than logic.
I would suggest some manufactures have to guess the box positioning more than others due to their pedigree and longer boxes makes the guess less prone to criticism but adds significant weight.
Common sense suggests when the board is 8ft long the degree to which the mast placement will vary is even less.
Now in prone we have all developed the habit of pushing the foil forward till it causes a problem for take off and then we just move it back a little and call it optimised because we all were learning to pump and it made it easier. This would be a very poor approach to positioning a lift 120 or and rs850 on a dw board.
Just thoughts and observation but so far no logical explanation to support such a wide variation in mast placement for dw.
When I was fretting about my tracks being too far back for my liking, and reviewing all the emails about measurements from the tail, I was thinking that with these long boards a better standard might be: some part of track like front or center a half-stance BEHIND center of floatation of submerged portion of board.
@FoilMad I’m not sure I entirely follow your point but one thing I did want to question is what the position of the mast has to do with anything.
What I understand and imagine is more important is where you stand (Centre of Gravity) in relation to the front wing (Centre of Lift). I think basing the judgement on the mast based on videos both doesn’t give an accurate enough measurement for your point and I think is likely also irrelevant. I think what you would find is that almost all riders when fully trimmed and moving comfortably will have their CoG just forward of or nearly directly above the CoL, and then trim by shifting their weight forward or back by bending the knees.
This trim principle (also applying to airplanes) gives the best balance of efficiency (least drag) and agility, and this trim I’d guess is what we intuitively end up with.
A possible explanation would be that the variation is due to the variation across brands of the distance between the foil’s centre of lift, and the centre of the mast.
I look at the col more as a dynamic turning moment which the rider must counteract for level flight. The turning moment or force is a function of the lift produced by the front foil applying its force over a lever that is multiplying its effect around a centre turning point that’s location is likely dynamic as it moves as speed increases or decreases. The stab contributes to this turning moment in the same way with down force and it’s lever distance from the centre of the dynamic turning moment. The effect of all this turning moment is felt by the rider as front foot pressure that varies with speed.
My observation and experience is that regardless of all this theory the best riders have come to a point where regardless of brand they have tuned their setup and stance so their back foot is directly over the mast. This makes sense to me as although we need to control the flying height with the front foot, controlling the roll during high performance direction changes is more critical and largely achieved best with the back foot directly over the mast. Too much in front or behind messes up the control of lift while turning.
The best are managing all the variations in lift that come from all the different brands and their tuning and the speed changes with their back foot on the mast.
So for me although the front foot mostly controls lift we are tuning our setups and stances around controlling the forces of high performance direction changes by anchoring the back foot above the mast. This makes the mast the reference point in my mind not to mention that all these dynamic forces are also acting through the mast to the rider.
Now to down winding. If these riders are managing the biggest variations in lift while flying with their back foot on the mast then I start to wonder why the need for so much variation in mast positioning in the tracks.
We have one sweet spot on the sup to paddle in our surf stance for the paddle up and is a result of the foam distribution. Now if the boxes are centred under the back foot of the average rider in this ideal balance point then you would think that most variables in foil lift can be accommodated within the adjustment of the tracks.
Now I think getting this correct is tough for the average rider as it is not as simple as prone mast positioning. On a dw sup if you put the mast too far forward it maybe the extended tail you are creating that is preventing the rider from bouncing on to foil. So we are hearing my boxes are too short as I can’t get my foil far enough forward to create lift yet moving forward might be the problem.
I note overnight instakahi paddling a barracuda with small tracks on a lift 120.
Yes that does make sense, with a plane you trim for level flight with the stab flaps, so the CoL would be dynamic. I started to look at free body diagrams to try and get specific but there are too many years since I last looked at them. If any engineers can show the component and then effective forces that would be cool.
So this video shows exactly what you mean, 3 brands (gofoil, axis, unifoil) all 3 riders dead on the mast.
Agree with you that the balance point of a board for paddling is almost certainly fixed. Anyone that has surfed or SUP extensively will know that it is a matter of cm between a board that paddles perfectly and too much nose/tail weight. Maybe they don’t know but it is intuitively discovered.
Paddle up observations below, not much to make of it, other than maybe your paddle position is forward of the box once things are balanced and tuned, and you’ll shift your weight back once up and riding.
So I think I get where you are coming from: why can a board designer not calculate the correct position for the foil box based on the balance point of the board, as this is the only time where the rider is limited to where they can stand. Once they are up on foil they will adjust their feet to trim the foil intuitively.
Is this broadly your angle?
I can imagine this working for highly competent riders, but almost certainly not worth the risk for board production to take such a bold step. It does open up using tuttle boxes instead of the tracks.
