4in1 sup/windfoil/surfoil/windsurf

Foiling related talk in here
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Gongmob
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Re: 4in1 sup/windfoil/surfoil/windsurf

Post by Gongmob »

Hoping someone can help. I have converted my foil sup to take a wsurf sail. (Gong mob 2taste 7'11). I have drilled holes in a deck plate so it attaches to the foot strap holes.
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(Where your front foot would normally be when sup foiling) there are a few options so have can move fore or aft as needed. I set up the foil close to the back of the tracks. My first attempt was with the large wing but i only got a few seconds flight. Wind was light maybe 6-10 knts. I decided to put the xxl wing on as wind was light. Wind picked up marginally and with ther larger wing it wanted to fly. But when it came out of the water it veered downwind every time and crashed. I wasn't moving or off the centre line so i couldn't understand why it was doing it. Could it be the mast track was too forward? Is that normal and just part of learning process? Foil need moving or wedging? Feet position i tried on top and behind foil. Didn't seem to change. What were the reasons other folk have used a wedge on the foil?
ronnie
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Re: 4in1 sup/windfoil/surfoil/windsurf

Post by ronnie »

I used a wedge to align the foil so that it was not angled down into the water when I was trying to get the board moving forward fast enough to get the foil to lift. eg. on my Fanatic Gecko 112, I found the area of the underside of the board that I thought was the main area used to get the board planing, and used a large square to set the mast at 90 degrees to that. You can use feeler gauges to measure how much of a wedge is needed under the base plate. In this case, it was 2.8mm.
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With my JP Slate SUP, it had no planing surface, so I went by the least rockered area which was going to be contributing to lift when getting the board moving and which would leave the board slightly nose up when flying - in other words, a best guess. I found that would need a 9mm wedge, but bought a 10mm and that seems to be working OK. The JP has a LOT of rocker.

As for the Gong, from what I have read they seem to have done a lot of experimenting with many types of boards (including windfoil boards) so you could ask them about positioning things. I asked Zeeko for information on modifying the Gecko and they gave me good advice on where to place the tracks in relation to the front foot straps for that particular foil.

I've just measured my JP 7' 2" which has a large swallow tail. From the centre of the tail to the sail mast base mount screw is 123cm. From the centre of the tail to the back of the track slots is 30cm. So the rear bolt of the GoFoil IWA surf foil base would be 92cm from the sail mounting insert. The bolt pattern is 165mm by 90, so from the centre of the foil mast to the sail mount insert would be about 84cm. When I am flying that board, my front foot is only a few cm behind the sail base, and it feels balanced like that.
Balz Muller mentioned using 85 cm in this clip, but he is using a windfoil, not a surf foil, and with a surf foil, the lift is further aft, due to the front wing being closer to the foil mast.


Your Gong board seems to have the tracks much further forward than they are on my board.
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My experience of screws for foot straps is that they are sometimes not designed to hold heavy loads, so if it were me, I would be putting as many screws through the mast base as I could and leave it permanently on the board unless the strap mounting holes are threaded metal.
Gongmob
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Re: 4in1 sup/windfoil/surfoil/windsurf

Post by Gongmob »

Thanks. I have made a few measurements. The distance from the centre of the mast foot (as it was on my first attempt) to the front of the foil is approx 65cm. So roughly 72cm to the centre of the foil? I had the foil back in the track but not all the way. Should i try getting that distance longer then do you think? I could add 2.5cm by moving the mast foot forward and maybe a few cm by moving the foil right back in the track. I think there may well be significant rocker but need to find a suitable straight edge to see if a wedge is needed. Btw i have 4 screws holding the mast foot. Seems solid
Gongmob
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Re: 4in1 sup/windfoil/surfoil/windsurf

Post by Gongmob »

Mine is also swallow tail but 7'11 centre of tail to centre mast foot is 140cm or 142 if i move it forward
Smidge
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Re: 4in1 sup/windfoil/surfoil/windsurf

Post by Smidge »

I would be very worried about the 4 screws, especially with the tendon joint (stiffer than a rubber BOGE). I recently sheared through a UJ pin whilst catapulting, so needed rescuing - the same crash would likely have ripped out your 4 bolts or the plastic they are attached to (maybe put some big washers to spread load on plastic). If it were me I would only use this board somewhere that you either have rescue cover or can safely drift downwind and down current to the shore.

Now thats said, I suggest putting your foil as far back as possible given your tracks will be optimised for sup foil use - certainly if its a windfoil. You dont want it more than about 110cms from where the front tuttle bolt would be (if you had them!) to the mast foot centre - but as Balz shows they can be a lot shorter (and my 4in1 has that distance a lot shorter). For windfoiling the front wing should be approximately between your legs so that you can balance over that.

For foot positioning, look at where the footstraps are on a good freeride foil board like a slingshot or a Naish hover. Your front foot needs to be in the equivalent position before the board takes off (then never move it) - so well outboard of the centre line. Maybe put some dots on your board with a marker pen as a reminder. Your back foot (at first) should be roughly on top of the foil mast or slightly outboard of that - once up you might want to move it slightly.

Ideally start learning in about 12 knots of wind average. When its really light (or really strong) its almost impossible to correct any errors in trimming before it all goes wrong......
ronnie
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Re: 4in1 sup/windfoil/surfoil/windsurf

Post by ronnie »

Gongmob wrote: Thu Jun 20, 2019 11:54 am Thanks. I have made a few measurements. The distance from the centre of the mast foot (as it was on my first attempt) to the front of the foil is approx 65cm. So roughly 72cm to the centre of the foil? I had the foil back in the track but not all the way. Should i try getting that distance longer then do you think? I could add 2.5cm by moving the mast foot forward and maybe a few cm by moving the foil right back in the track. I think there may well be significant rocker but need to find a suitable straight edge to see if a wedge is needed. Btw i have 4 screws holding the mast foot. Seems solid
If it was my board and I could use 6 screws to fix the mast base to the deck, I would do it. I've had to replace strap mountings that pulled out of a board, and also had problems of screws being ripped out of the plastic, especially if they had been screwed in and out several times.

I only used the IWA once overpowered and found it was difficult to keep it from breaching, so if I was going to do anything to my IWA foil setup, I would have used the extra holes in the base to move it further back by 2cm so the mounting distance between the centres of the 2 masts would have been 86cm. I had originally requested the tracks to be 5cm further back, but they were put in 5cm forward of what I requested.

It seems that you could only get a maximum of about 77/78 cm between the mounting centres of the 2 masts?

eg. This looks to me like the foil is mounted too far forward on the board - relative to the sail base.


This one looks like it could maybe be at just enough spacing for windfoiling, and maybe can also be used without the sail for SUP foiling?
These are his posts on modifying a SUP foil board to windfoil.
http://mauisurfreport.blogspot.com/sear ... %20foiling
Gongmob
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Re: 4in1 sup/windfoil/surfoil/windsurf

Post by Gongmob »

Thanks for the tips. Noted about the extra screws. Shouldn't be too difficult to get another two in but has already withstood numerous crashes.
If 85 cm is the minimum spread, am i at a lost cause then do you think?. Probably could get close to 80cm at full stretch.
ronnie
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Re: 4in1 sup/windfoil/surfoil/windsurf

Post by ronnie »

Gongmob wrote: Thu Jun 20, 2019 8:07 pm Thanks for the tips. Noted about the extra screws. Shouldn't be too difficult to get another two in but has already withstood numerous crashes.
If 85 cm is the minimum spread, am i at a lost cause then do you think?. Probably could get close to 80cm at full stretch.
You could max it out and see how it foils. Paolo says that he prefers it when his front foot is pushing on the mast base and his rear foot is over the foil mast, but he also said that he thought there was massive room for improvement.
Gongmob
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Re: 4in1 sup/windfoil/surfoil/windsurf

Post by Gongmob »

Right i went out on the lake today with the new settings. The wind was a bit light still but had a few gusts and tried to pump more. First flight ended in the usual swerve downwind and catapult. The second one it felt like the board was planing, then it lifted up out of the water and stalled and the board hit the water nose first. I am not sure if it was high enough that it breached but it felt like that. Then i tried moving front foot to windward slightly. It seemed to stall on lift off. And one time luffed up.
I think i am going to try and see if it needs wedging. I think from looking at the rocker line. That it is not balanced and maybe causing the stalls?
ronnie
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Re: 4in1 sup/windfoil/surfoil/windsurf

Post by ronnie »

Gongmob wrote: Fri Jun 21, 2019 3:55 pm Right i went out on the lake today with the new settings. The wind was a bit light still but had a few gusts and tried to pump more. First flight ended in the usual swerve downwind and catapult. The second one it felt like the board was planing, then it lifted up out of the water and stalled and the board hit the water nose first. I am not sure if it was high enough that it breached but it felt like that. Then i tried moving front foot to windward slightly. It seemed to stall on lift off. And one time luffed up.
I think i am going to try and see if it needs wedging. I think from looking at the rocker line. That it is not balanced and maybe causing the stalls?
Given how far forward the tracks are, it seems that it is a bit less likely to need a wedge, but it is possible it might.

What I would do is to try it when there is enough wind for it to fly without pumping the sail.
Keep my weight forward to keep it on the surface and with the rear foot on the centreline, and the front foot with my toes beside the mast base. Then if I got to a speed where I could feel it getting light on the surface of the water (like the board is hardly being kept level fromside to side by the water - ie. it feels 'loose' and 'floaty'). Then move my weight aft very slightly, to try to get it to lift slightly off the water and if it lifts off slightly, then move my weight slightly forward again to put it back down on the water.

Don't be in a hurry to get it flying for a length of time. Just experiment with finding the balance point for lift off and where your feet and weight have to be to get it to lift off slightly and put it back down.

I don't think you need to worry at this point about it turning downwind or upwind - just try to find out the foot and weight positions for fore and aft balance.
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