Getting ejected out the front door...

[Solent Foiler]

I'd rather have a rigid mast that works in most of the circumstances I use it for than a floppy one that eliminates a condition I rarely encounter. But that's me.

There would be a elegant symmetry if lighter riders needed a thinner mast to reduce ventilation and don't need the stiffness vs bigger riders who need the opposite! I guess Axis might be ahead of the game by offering 2 different thicknesses then!

I wonder if lighter riders cant their masts to windward more than bigger riders making their situation worse?

[Dwight (DW)]

I'll try and wing with more and less yaw. I'm mostly going upwind to the max so I can ride downwind.

Never yaw the board. Bank angle is the correct way to drive upwind.

[JohnnyTsunami]

I just had a session and was thinking about this. I find when I put my rear foot further back and more center where my rear strap would be (it's usually a bit on the downwind side of the board and more forward) I lean over more and yaw less.

Makes me wonder if this is the reason kitefoil racers have a RIDICULOUSLY wide stance - to be in a better position for optimizing upwind and preventing mast ventilation? Makes sense that wingers would have this problem with our relatively slow speed we have our feet closer together and get away with it unless we're hauling ass upwind.

Just a bunch of guesses...

[PonoBill]

Probably a pretty good guess. Adding yaw increases lift in the upwind direction by increasing the angle of attack (good!) but that lift is generated by differential pressure across the foil (bad!) which is something we can get away with when our wing is fully submerged, but turning a surface-piercing mast into a wing by increasing the angle of attack does the same thing as popping a wingtip out of the water.

[Solent Foiler]

Just to update the thread, I've finally had a couple of sessions on the modified Gong mast with the 999 and it's all good! The repeated ventilation has gone, which is a massive relief -  can get back to focusing on getting upwind as hard as possible.

What this whole experience ha done is made me more aware of the issue, and actually the Gong mast did ventilate a handful of times, but only when hit by a large white cap in big winds, right on the sweet spot which would be difficult for anything to handle, and if on flat water, it would begin to ventilate, but it just quickly sorted itself out without any action from me. I probably didn't notice it when I used that mast in the past...

The new setup is 500g lighter than the Axis mast, which is noticeable lighter, even just carrying my kit to the water. Stiffness wise it's difficult to judge because I'm now using the 375P tail rather than the 380, which way looser, and much more to my liking. I've even ordered the 350 now there's more to squeeze out of the 999 as a windy setup... Looking forward to giving that a go, but it's getting cold in the UK now, which always makes me feel like a kook again...

[PonoBill]

cool, I've had a somewhat square rubber band on my mast for a while to defang ventilation. I didn't have an issue before, and I'm not having it now, so it's working--at least as well as a SharkBanz does. Are those guys still around and not in jail?

[Alysum]

Just to update the thread, I've finally had a couple of sessions on the modified Gong mast with the 999 and it's all good! The repeated ventilation has gone, which is a massive relief -  can get back to focusing on getting upwind as hard as possible.

What this whole experience ha done is made me more aware of the issue, and actually the Gong mast did ventilate a handful of times, but only when hit by a large white cap in big winds, right on the sweet spot which would be difficult for anything to handle, and if on flat water, it would begin to ventilate, but it just quickly sorted itself out without any action from me. I probably didn't notice it when I used that mast in the past...

The new setup is 500g lighter than the Axis mast, which is noticeable lighter, even just carrying my kit to the water. Stiffness wise it's difficult to judge because I'm now using the 375P tail rather than the 380, which way looser, and much more to my liking. I've even ordered the 350 now there's more to squeeze out of the 999 as a windy setup... Looking forward to giving that a go, but it's getting cold in the UK now, which always makes me feel like a kook again...

Thanks for the update, how thick is the gong mast.

[Solent Foiler]

Thanks for the update, how thick is the gong mast.

Good question! Just measured at the point the mast was shortened, and it was 14.5mm across the cut. Obviously tapers to more closer to the plate, but difficult to measure accurately there as my calipers don't quite reach to the widest point but probably around 16-17mm.

Certainly suggests that thinner is better from a ventilation perspective...

[Alysum]

Well the axis carbon is 14mm at the bottom... Unless most of my ventilation happens further up the mast.

Hopefully the Axis v3 carbon mast fixes the issue, whenever that comes out.

[surfcowboy]

Dig that. At the end he says he doesn't recommend sanding aluminum masts but who wants to try with a little matte clear poly or other matte paint?

Axis is anodized. Gong is painted and not glossy.

Windsurfers, who knew they knew stuff? 😉

[Alysum]

Very interesting... And it's ventilation he experienced (not cavitation). So who's sanding down their axis carbon mast 

[surfcowboy]

Oh he says to not sand aluminum but I am wondering what Solent thinks about the painted Gong vs smooth anodized Axis.

[Dwight (DW)]

So who's sanding down their axis carbon mast 

Evan sands all his. Mine is sanded now.

[Solent Foiler]

Oh he says to not sand aluminum but I am wondering what Solent thinks about the painted Gong vs smooth anodized Axis.

Tough one... The finish on the Gong mast is more a satin clear coat and could probably do with a refinish so is hardly special. I've been using an old Naish aluminium mast a lot too which is more a matt finish and didn't have any ventilation issues. All three masts are very different shapes so isolating the factors that might contribute to ventilation is difficult.

Having said that, I would be astonished if sanding fixed the Axis mast. It's so far away from giving me acceptable ventilation performance that I'm struggling to believe that a bit more turbulent flow over that section shape would make a significant difference at the speeds I'm operating at. At the higher speed of wind foil racing, I could see that making a difference, but I'm speculating really...

I've heard so much pseudo science on roughed finishes that I'm sceptical of believing anything I haven't tried for myself. Not saying it doesn't work, but that the application is quite specific.

[Solent Foiler]

Fishman - I do have a Gong V2 mast but only recently got it and only used it with my big foil. I will try it with my Fluid LS this weekend and see how it behaves... I normally use one of the older thinner Naish masts (similar to the Gong V1) which fits my modified Gong fuse with the LS...

Took out the Gong V2 aluminium mast today with the LS and it was just as bad as the Axis aluminium mast for ventilation. Pretty disappointed really. It'll be fine with the big XXL-S, but I won't use it with the LS again. It has a very different profile to the Axis - more teardrop, but 2mm thinner, so 17mm so had high hopes it would be fine for me. Finish is not as shiny as the Axis. I'll have to stick with the Naish for the foreseeable or get a V2 Gong carbon mast...