Occasional when on foil usually after getting going in windy conditions or after turning I get the feeling the fin has no grip or balance and is unstable, resulting in me tumbling in the water. Just wonder what is going on with the foil to cause this situation. I'm not breaching and it only happens very occasionally. I can't figure out what I'm doing to cause it and why the foil feels solid at all other times in same conditions and turns.

Mast ventilation possibly. Learned over you can get an air pocket on the mast which travels down to your foil. Essentially the same as breathing.

What foil, mast, fuse, stabilizer are you using? I had ventilation problems on the Cedrus Evolution mast when I would lean over in turns. You can look at the pictures in this post and see if any of these issues show up on your mast:

www.wouzel.com/post/600-miles-in-the-gorge-reviewing-the-cedrus-evolution-surf-77-5

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BWalnut said..
What foil, mast, fuse, stabilizer are you using? I had ventilation problems on the Cedrus Evolution mast when I would lean over in turns. You can look at the pictures in this post and see if any of these issues show up on your mast:

www.wouzel.com/post/600-miles-in-the-gorge-reviewing-the-cedrus-evolution-surf-77-5

40 emails? The customer is always wrong?

First thing you should do is clean your foil, do it at home with soap and water, get any greasy finger marks off it. Then once assembled at the beach, clean again with windex before going out, and don't touch it. It's amazing how much better a clean foil works.

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airsail said..
First thing you should do is clean your foil, do it at home with soap and water, get any greasy finger marks off it. Then once assembled at the beach, clean again with windex before going out, and don't touch it. It's amazing how much better a clean foil works.

Haha how good is it when you do that and have your foil perfect and then just before you go out someone comes over and grabs your foil trying to flex it and wiping their greasy little mitts all over it

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airsail said..
First thing you should do is clean your foil, do it at home with soap and water, get any greasy finger marks off it. Then once assembled at the beach, clean again with windex before going out, and don't touch it. It's amazing how much better a clean foil works.

Sunscreen is a major culprit.
I lightly sand it with beach sand before going out if I think the gear may have something greasy on it by chance. Works pretty well.

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MProject04 said..

BWalnut said..
What foil, mast, fuse, stabilizer are you using? I had ventilation problems on the Cedrus Evolution mast when I would lean over in turns. You can look at the pictures in this post and see if any of these issues show up on your mast:

www.wouzel.com/post/600-miles-in-the-gorge-reviewing-the-cedrus-evolution-surf-77-5

40 emails? The customer is always wrong?

150 and 6 months by the time it was done.

I did have similar mast ventilation problems with my Original Cedrus in Combo with the Cabrinha H series foils and with certain SAB foils. Pretty much every session it happened. cleaning and sanding helped a bit it was never gone
With the Kujira,s there was no problem at all wich made me believe that at least some foils are very hard to get ventilated.
Now that i,m on the AFS UHM80 I havent had a single mast vent ever, so mast do make a huge difference.

Ventilation occurs when the low pressure region created by the foil sucks air down the length of the mast which results in loss of lift. It is very complicated, and can depend on variables from salinity to water temp to chop level and of course to mast/foil designs.

The Classic Cedrus was designed in 2017 and did suffer from ventilation at higher speeds and angles of attack relative to the wind. Ventilation wasn't really understood or experienced back then and became more prevalent as foils got faster. This was the primary motivation for a complete redesign in 2023 and resulted in Evolution Wind, which features a patented design and longer chord length in the piercing region to prevent flow separation (which can lead to ventilation). We have not had any reports of ventilation with an Evolution Wind mast. This mast is used by our clients all over the world tow-foiling in Hawaii at 30kts, wing foiling, kite foiling, and on DW runs.

Evolution Surf is designed specifically for low speed prone foiling. Ventilation is extremely uncommon for prone foilers. As a result, This mast features a shorter chord length to reduce wetted area and increase glide. It is not designed for wing or kite foiling, although many wing foilers are going this route if they are truly down-winding. It's not designed to sail close-hauled, and won't point as well upwind. All of this is outlined very clearly on our site. It is designed to be ridden at a very specific height for maximum efficiency in the surf. Due to the shorter chord length, it will be more prone to flow separation, which can happen in very tight radius turns and/or when tips are breached. Simply put, it's less forgiving, but offers industry-leading glide/pump performance.
We are not going to engage further with the specifics of this incident, but simply want to clarify our deep and long history with ventilation and how it's impacted the design of our products. We have reviews and videos coming which offer more insight into the differences between the two models. Feel free to contact us through our site if you have any questions about our masts. We understand the currency exchange rates and duties/shipping have made Cedrus very expensive in Australia and we are working on ways to address that. Thanks for your patience and support.

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BayAreaKite said..
We have not had any reports of ventilation with an Evolution Wind mast.

Actually, the user who stepped up and helped me identify the problems on my Evolution Surf mast was on an Evolution Wind mast that was ventilating at high speeds. They told me they shipped the mast back to you to have it refinished since it had flat spots on it.

Every single company is going to have gear issues. IMO it's impossible to have 100% perfect manufacturing. That's fine. I think all consumers understand that and I know I do. I think that the sooner any company stops thinking "how can we prove our product is perfect?" and moves to a model of "how can we best take care of the clients who trust us with their money?" the better.

Here we go again...how did this back and forth work out on The Progression Project forum?