Hi All, Stephen from the UK here. I have had my Hover Glide 76 for over a year now and absolutely love it and here where I sail at Felixstowe in East Anglia there are at least 12 of us on Slingshots but after a spate of breakages here including where people have lost thier complete foils with bolt failure also bent mast and fuselages. I then broke my fusalage and was amazed that my front wing floated to the surface when I was in the water but was badly damaged where it hit the mast. I was lucky it happened close to where I launched as I had been several miles down the coast before! Now we are all very nervous of using the foils and some are quickly swapping to Starboard which are much better engineered. A particular weak point is where the mast joins the fuselage, the matter is in the hands of Slingshot UK at the moment and I am waiting to hear the outcome but they must be concerned. This brings me to the latest Phantasm windsurf foil range, I would love to continue using Slingshot and the carbon range look fantastic but no one seems to know when they will be available? So has anyone had any idea when you can buy one and also have you had any trouble in Australia with Slingshots failures ????

Aluminum fatigues over time and then breaks, carbon does not under normal use, aluminum also corrodes in saltwater, carbon does not. those are two reasons, out of several more, that I went with an all carbon AFS foil, mast/wings/fuselage.

Keep in mind that 5 of the first 10 thread topics currently in the forum reference Slingshot in their titles, with at least two other sthat are pretty much all about their gear. For market share, especially where I live they dominate probably 3:1 over the nearest rival. I have to think pretty hard who that rival would even be, LP, AFS Foil, Starboard who knows?. This is why I believe we hear more about their failures. That said, yep aluminum fails catastrophically when it goes. Not many people are posting about how long their gear has held up, as it normally just works and doesn't warrant posting. Mine has been to hell and back, though I expect it will fail eventually if I don't replace the fuse to mast bolts or the fuse itself.

It's why windsurfers should never trust a kite company ;)

Two simple reasons why you will read more about Slingshot foils than other brands in this forum. Slingshot foils have been available as a modular system aimed at free riding for nearly three years now. You can use them for wind foiling, sup foiling and wing dinging. Most of the people seem to be either from the US or Australia. On both those markets other systems have either been hard to get hold off or have not had a clear interchangeable product line.

I think this will change a bit in the next couple of years but for now they have a big lead.

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westozwind said..
It's why windsurfers should never trust a kite company ;)

Ever heard of Logosz boards???

Hello, Squiz/Stephen,

Re photo 4. The area to the LH side of the front bolt shows a classic fatigue failure, evidenced by the "oyster lines" moving/pointing downward towards the mast. The oyster lines show that the crack was present for some time and probably started near the top of the countersink, then progressed towards the mast.

The rough surface below the oyster lines and over on the RH side of the fuselage is an impact failure, where the metal fails instantly, because the cracked area is no longer supporting the load and the remaining metal also cannot support the load.

I would expect that a surface crack would have been present near the top of the countersunk area but it could be easily missed if you were not closely examining the area as you were assembling the foil.

Whilst Sandman is correct that aluminium fatigues over time, I think that the cause of this failure may have been be due to a nick somewhere in the countersink. I also think that the crack started fairly recently, because the oyster lines are so pronounced. If the crack was old, the two sides of the crack would have been rubbing against one another under load, polishing both sides.

Hope this helps.

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Sandman1221 said..
Aluminum fatigues over time and then breaks, carbon does not under normal use, aluminum also corrodes in saltwater, carbon does not. those are two reasons, out of several more, that I went with an all carbon AFS foil, mast/wings/fuselage.

Carbon fatigue is real and even more difficult to quantify than aluminium fatigue.

The bevel of the countersink meeting so close to the bevel along the length of the fuselage isn't a great idea. Sharp corners like that are a stress point. A couple of mm of flat either side would strengthen it dramatically. Saying that though, it's the first broken fuse I've seen.

Stephen
I would never have considered windsurfing on the Orwell but looks like a good foiling spot. Is it a high tide spot only? From what I remember it's pretty muddy either side at low tide.

That really is a shoking photo. Here at the lake also Slingshot is clear leading the windfoil market.
At Kite it's clearly Moses mostly 633.

Out of my point of view the construction is really not the best one. Also when I'm really fan of SS out of engeneering point this should need to be improved.

But:
The WINGS and the system is working great and making a lot of fun also when I have again and again a look to other brands and have la ook what they do. Some other constructions look much better but are they tested in the same way as the slingshot ones?
One weak point is the connection between mast and fuse. All the forces need to be taken by two bolts. When one breaks the foil gets lost. Urrrgggg.....
This is anoing...good thing with the mast you can still return and windsurf with a 90cm fin :-)
When I look to other brands the fuse has a notch for the mast. The forces are hold more stable as the mast fit's very exactly in the fuse. But when I see a break like this I need to ask where is it coming from?

I want to bring in some points or draw a little picture:
Slingshot is used from big part of the windfoilers market. What philosophie is slingshot selling?
Baaaammmm....Go out have Fun in Freeride Foil, in early lift, with small sails, learn new moves, jump away in 11 knots.

What do people use slingshot foils?
Yes the do exaclty this. They try new moves, they start jumping and jump more and more, higher, loops in flat water etc. ... jumps they have still not learned with fin because of to less options.
But jumping with the i76 (1500cm) or bigger wings is quickling showing the weakest point in the system.
By until now I see less brands (except Horue and partyl Moses - but in germany Moses is rarely by windfoilers) that sell this kind of Windfoiling Style. Because of the quick learning curve on the SS foils the people try this kind of moves more and more. As long as they don't jump with the i76 or bigger I have still not seen any failure. The bumg and jump wing is the i65. And out of my experience this makes also much more fun and the system is working fine. Almost at our side here.

Brands like starboard sell more the freerace style. I think that with only foiling the most constructions have no bigger failures. The loads are less and the system can absorb the forces much easier.
When you do a deep preload with the i76 and then push it agressivly out of the water the load on fuse and bolts it really crazy. Try it with the wings at the fues only in the water by your hand.

A final ting I can confirm: If something breaks inside the warranty phase you can rely on Slingshot. If you bought it new and you're inside the 12 months warranty you can contact them.

I recommend also to think about a kind of material insurance for damages at your own material. This will help you also at used / second hand bought Material. In germany this exists for 100 Euro / year. For less fear about my material for me it's worth.
At foil everything is to expensive. Foils over 1000 Euro, Foilboards over 1500 Euro.

Phantasm seems to be a really great upgrade and also I'm waiting for it. But it seems to be worth to wait for the phantasm and not invest in the old ghos wisperer line (that was the comparable line to Moses).

Stephen, Grant here from Australia. I work for Slingshot as there communications manager. Good to know you have taken it up with Slingshot UK. I would also suggest getting in touch with Wyatt Miller he is the windsurf manager.
From my point of view we have not had catastrophic failures like that, we like any brand have had several issues with our construction. Of course we will do all that we can to look after our customers.

The Phantasm range is just starting to drop. The 633 below is 1 of only 3 in Australia. The 730 & 657 kite packages are on back order.
The manufacturing difficulties presented by the Covid have created havoc with our time line and delivery dates. Put this together with the unexpected demand and you get very little product getting to riders.
AS for when the Wind range will drop, Wyatt Miller will know more.
Hands on, these things are a work of art, stiff is an under statement, the build quality is exceptional.
Stoked to here you are still looking to our new product for your future needs.

Cheers
Grant Hore

Even SB stuff is breaking. I got the job to fix it.

You're not the only one.
This was covered under warranty
I understand with catastrophic failures like this it's hard to trust the same product again.
Been there and done that.


This is a known issue here in the Bay area (San Francisco).
There are better sets on the market that are available and proven.

The Slingshot fuselage is definitely a weak point in the system. It was originally designed for kiting, with short fuses and a mount in the A position, where the mast is directly under the front wing. There is very little stress on the fuse in this setup since the upwards push of the front wing is aligned with the mast. The only torque on the fuse is from the stabilizer, which is much smaller than the front wing.

When getting into the windsurf market, Slingshot had to move the front wing further forward. They added the B and C positions, and increased the length of the fuselage. But this dramatically changes the load on the fuselage: the offset front wing now tries to bend the fuse all the time. Slingshot chose a pragmatic solution when a re-engineering of the fuse was called for. Other companies who got into foiling later started from scratch, and (mostly) came up with more robust solutions.

On the bright side, Slingshot has been very good about honoring warranty claims. They had to - if they'd pulled a "Locosys" on the market, nobody would be using Slingshot foils anymore for windfoiling. I had a front wing split, which SS replaced very quickly. I also had a fuse break, but that's because I added an extra hole for a "D" position. Fortunately, the price of a SS fuselage to replace the broken one was not so bad, and the front wing did not get damaged.

I'd wish that Slingshot would re-design the fuselage to make it beefier at the mount. But as Gwarn's image shows, the fuse can also break at other places, which would be much harder to change than the mast mount points for B & C position. But at least the fuse and mount points in the Phantasm have been redesigned and look a lot sturdier.

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Sandman1221 said..
Aluminum fatigues over time and then breaks, carbon does not under normal use, aluminum also corrodes in saltwater, carbon does not. those are two reasons, out of several more, that I went with an all carbon AFS foil, mast/wings/fuselage.

Sandman1221 , while carbon fiber does have advantages in a saltwater environment, it takes 100,000s to millions of cycles for aluminum to fatigue to failure when properly engineered. No recreational foiler should be approaching that. The "aluminum fatigues" argument was used against alu bikes they first came out yet after 30-35 years the first generation of Treks and other brands have held up fine. I'm going to go with WindmanV's assertion that there was probably a nick or flaw in the countersink.


Not to mention some of these still flying after 60-70 or more years. Yes, fatigue has grounded lots of planes but only after an incredible number of cycles.

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PatK said..
Even SB stuff is breaking. I got the job to fix it.

That's odd that one end failed. Do you know if it was impact/grounding, loose screws or a flaw in the layup? That looks like the leading edge where the force would have been in compression on that barrel nut?

A break like those shown in the photos above are clearly a manufacturing defect and are covered by warranty. The failure is very inconvenient and even dangerous, but SS will support warranty replacements.

That said, any nick in the area of the bolt holes is a recipe for disaster since it introduces a stress riser. Aluminum or carbon, doesn't matter. Just nick a sail mast and watch it snap. Nicks are how you cut glass and tiles, too.

Fatigue is another matter altogether. Repetitive stress can introduce fatigue in most metals, but not carbon. You see it in the grain structure, which carbon does not have.

At Boeing, they measure the lifetime of aluminum airplanes by the number of pressurization-depressurization cycles they will go through. That is fatigue of the aluminum structure of the fuselage, and they tear them down to their naked states often to measure this. Also, the skin stringer shear-tie frame structure stops any fatigue cracks from spreading. When those cracks appear, the airplanes end up in the Arizona desert boneyard. Other than the one topless 737 in Hawaii that time, there has never been a fuselage failure of an aluminum airplane, by Boeing or anybody else.

All of this is different with the 787, which is all-carbon. There is no pressurization cycle fatigue in carbon, so they don't even know yet what the overall lifetime of a 787 will be, but it will be many times that of an aluminum airplane, based on calculations and lab testing. Yes, they also tear down the 787 to its naked state to inspect the structure. They never find any kind of fatigue aging. Since the carbon is so strong, they pressurize the 787 to a higher level in flight, 4,000 feet altitude equivalent rather than the 8,000 feet altitude equivalent for aluminum. This makes the flight nicer and more comfortable for passengers.

Back to our sport. To my knowledge, most foils use aluminum fuselages, with a few exceptions that I know of, such my AFS-2 and LP FRS. Even my Moses Race has a long aluminum fuselage. I have to believe, or hope, that the industry migrates to carbon for the fuselages. We will all benefit. Lighter, stronger, and more longevity if we don't nick 'em.

--RM, Retired Boeing Scientist

I had a similar break on a fuse but it was well used and abused. In some ways it is amazing that that entry level piece of kit I bought in 2018 was still on the water. There has been so much change in foiling since then, but the modularity of hoverglide allowed me to participate in these changes (mostly in new wings, but also foil tracks) without much additional cost.

Although no one is happy with breakage, it is part of our sport and the loads while wind foiling are intense, but at least with HG we can easily replace these pieces, very often under warranty.

Not an engineer here.
However, I have been around motorcycle road racing for a number of years and can tell you that carbon fiber fatigues rather quickly when used for motorcycle racing fairings.
If not dropped, maybe for 50 rides, triple that for smoother motors...ie Suzuki ... and less for Kawasakis, of the time period.
Rubber mounts help some, cork and soft fibers better.
Car fairings and wings are often replaced about the same usage rate, those not crashed.

Thank you for all the reply's, very interesting to hear your stories/reports:) I have just heard from Slingshot UK that they are replacing my fuselage even if out of the years warranty so no complaints there but my front wing has a nice chunk out of it so this has really effected the secondhand value but that is the nature of windsurfing, gear takes a battering I am afraid! I love the look of the new phantasm foil, perhaps I will have to start saving now as absolutely love my Slingshot foil:)

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segler said..
Other than the one topless 737 in Hawaii that time, there has never been a fuselage failure of an aluminum airplane, by Boeing or anybody else.

Cough, cough, Comet, cough. But to your point, much of that was not understanding the stress the window shape generated through pressurization cycles.

The confusion comes with the word "Engineered"
Windsurfing / Foiling gear is not Engineered, it is just trial & error, if it breaks make it stronger, if it doesn't make it lighter until it does.
The other problem is that most of the materials used are not designed for the purpose, they have been chosen as the best available option.
Time is the only thing that sorts it out, eventually the design develops to an acceptable standard.

Excellent point from AUS 808, and one true since 1978.

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AUS 808 said..
Windsurfing / Foiling gear is not Engineered, it is just trial & error,

Evolution in other words. Trouble with evolution though is that it's not intelligent design. It throws up something that sort of works in an environmental gap and then refines it. The starting point for kiting/windsurfing gear was a model aeroplane on a strut. It sort of worked, was pretty good upwind, had a smooth ride and was a whole new sensation. So it got a foothold and has been steadily improving through trial and error. But was it the best starting point? Tinkerers could propose what they thought was a better foiling format, build one up, but now being years behind in the evolutionary process, wouldn't stand a chance.

To break out of the rut you'd need to apply serious engineering and computer simulation. Who'd have thought the AC75s would just get up and go? You could try something similar on a windsurfer but without the R&D budget of an Americas Cup or Jules Verne trophy it would get blown away on debut and the idea scrapped as a nice try.

Be interesting to see what AA's research team comes up with in his 66 knot foiling project.

www.facebook.com/antoinealbeauf192/videos/3697650893618575

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Windbot said..

westozwind said..
It's why windsurfers should never trust a kite company ;)

Ever heard of Logosz boards???

Slingshot was founded as purely a kitesurfing company
www.thekiteboarder.com/2009/12/born-bred-in-the-usa-the-story-of-slingshot/
Quote:
"All our competitors at the time were windsurfing companies that jumped into kiteboarding. Slingshot was launched as a kiteboarding brand."

Prolly a 250-320 sq cm thin foil for AA's rather considerable size.

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LeeD said..
Prolly a 250-320 sq cm thin foil for AA's rather considerable size.

And maybe an even smaller surface skimmer up front mounted on something like a skate board truck. Self levelling but still with foot steering?

The failure on carbon fiber motorcycle fairings is not fatigue. It's good old fashioned delamination caused by the stress risers at the fasteners.

On the other hand, the 787 fuselage is GLUED together with very few fasteners. Those glued contact surface areas are VAST. No stress risers there.

Sidetrack. Thought Stealth Fighter needed carbon fuselage changed constantly, part by part, not all at the same time.
I tried reinforcing both Yamaha and Kawasaki fairings with added lamination on mounting points. My added layers worked, but the panels got soft and needed full layers added, making fit impossible and adding too much weight.
So I surmised the carbon panel got vibration worn from the motor and the passing wind.
Fairings shake like crazy at 170 mph back in 1976.

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westozwind said..

Windbot said..

westozwind said..
It's why windsurfers should never trust a kite company ;)

Ever heard of Logosz boards???

Slingshot was founded as purely a kitesurfing company
www.thekiteboarder.com/2009/12/born-bred-in-the-usa-the-story-of-slingshot/
Quote:
"All our competitors at the time were windsurfing companies that jumped into kiteboarding. Slingshot was launched as a kiteboarding brand."

That might be true but the founder Tony Logosz was designing, building and selling sailboards long before he founded slingshot. And he could be considered the pioneer of freeride wind foiling (circa 2015 and 2016).

www.instagram.com/p/9pNYzGOAQY/

www.instagram.com/p/BGs1joIuAYJ/

Not to mention wingfoiling in 2015

www.instagram.com/p/-IjGSeOASj/

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thedoor said..

westozwind said..

Windbot said..

westozwind said..
It's why windsurfers should never trust a kite company ;)

Ever heard of Logosz boards???

Slingshot was founded as purely a kitesurfing company
www.thekiteboarder.com/2009/12/born-bred-in-the-usa-the-story-of-slingshot/
Quote:
"All our competitors at the time were windsurfing companies that jumped into kiteboarding. Slingshot was launched as a kiteboarding brand."

That might be true but the founder Tony Logosz was designing, building and selling sailboards long before he founded slingshot. And he could be considered the pioneer of freeride wind foiling (circa 2015 and 2016).

www.instagram.com/p/9pNYzGOAQY/

www.instagram.com/p/BGs1joIuAYJ/

Not to mention wingfoiling in 2015

www.instagram.com/p/-IjGSeOASj/

+1

Slingshot, Ride Engine... the history of the founder is important. They made foils with LP & Moses in the beginning.

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Paducah said..

PatK said..
Even SB stuff is breaking. I got the job to fix it.

That's odd that one end failed. Do you know if it was impact/grounding, loose screws or a flaw in the layup? That looks like the leading edge where the force would have been in compression on that barrel nut?

The race foil is from 2018. So it has some hours on the water. No abnormal stressing as far as i know. But i upgraded to a 115+ fuse and a 1000 wing this season. Maybe this was stress to the carbon mast. I try to fix it.