How Did Vestas Sailrocket 2 Smash the Sailing Speed Record?!?!

In this video we talk about how Sailrocket 2 works, including how it smashed through the 50 knot foil cavitation barrier to break the sailing speed record at 65.45 knots (121.2 km/h) over 500m.
This video includes content for educational purposes under fair use principles.
Disclaimer:
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#sailing #foiling #howtosail #learntosail #sailingtips

[@Animationzz_os]

It may be a one trick pony but man is that a cool trick.

[@SailingTipsCa]

That’s a great way of describing it!!!

[@rize7737]

This channel is criminally underrated. Great job.

[@SailingTipsCa]

Thanks - glad you like it!!!

[@royshashibrock3990]

Great video...informative, to the point, not overly long, and no BS.

[@SailingTipsCa]

That was the idea - glad you liked it!

[@russelldesilva1560]

Despite its limitations, sail rocket 2 is indeed one of the coolest sailing contraptions ever devised. A spectacular feat of perseverance, engineering, and bravery. Don't care one little bit if there's only 1 place in the world it can sail that fast. 👍

[@SailingTipsCa]

Well said - I totally agree!!!

[@alexanderSydneyOz]

It is certainly uber cool, and just the toy for some rich, sail enthusiast, Namibian, who has everything else already

[@SailingTipsCa]

@@alexanderSydneyOz And it does keep the rest of us (non-rich) entertained!

[@martinpoulsen6564]

@@alexanderSydneyOz Well.... Vestas is far from Namibian... or even boatbuilders. But they do make offshore turbines, so I bet there's a ton of secret R&D hidden in there, that they could possibly use, and if not, it's still great exposure as masters of the wind. It's big corp budget on that thing, not just billionaire fun and games.

[@AJ-kv1po]

That pass reminds me of the olden days land and water speed runs using engines, just sittin there ready to die.

[@lavaljeantet]

I worked as HYDRODYNAMICIAN with the DESIGN TEAM of SAILROCKET during 15 months and, in fact, they DIDN'T SELECT a CAVITATING dual-mode foil, but RATHER TURNED THEIR MIND on a BASE-VENTED ULTRA LOW LIFT COEFFICIENT SECTION, with ONLY THE truncated BASE in a state of CONTROLLED VENTILATION fed by the air coming from the sea level....a more complex technlogy, but much more stable and less draggy......

[@SailingTipsCa]

Thanks so much for your expert insight!!!

[@johnnielsen7413]

THANKS, that is some GOOD insight. Have a nice DAY.

[@njr582]

NOW we KNOW

[@DoveWrestler]

INTERESTING INFORMATION. SPEAK UP, I COULDN'T MAKE OUT SOME OF THAT.

[@edjack1993]

The seemingly RANDOM combination of CAPS and lower CASE above is in FACT a perfect balance THAT HAS achieved THE most AERODYNAMIC KZbin COMMENT ever.

[@jamesdunn9609]

You explained a fairly complex subject in a way that anyone could easily understand. Well done! I grew up on the Chesapeake Bay and spent the summers of my youth sailing. When I got a little older I was fortunate enough to get an opportunity to sail on one of the Chesapeake Bay Log Canoes. I spent a year racing on the canoes which was a truly memorable time. Going fast on a sailboat is something everyone should do at least once in their lives. If you are ten feet out on a board it's even more incredible!

[@SailingTipsCa]

That sounds like lots of fun - I agree!!!

[@pohlec89]

Great video. I grew up cruising Mexico and the South Pacific, and follow (lightly) sail racing, so I learned about SailRocket 2's record years ago. However, this video provided a very concise summary of the mechanics, and I really enjoyed learning all of those details! Thanks for taking the time to create this!

[@SailingTipsCa]

Thanks so much - glad you liked it!

[@MattBaker1965]

I watches the whole Sailrocket project from start to finish. I was amazing the ups and down the crash and the indomitable spirit of the team. Thanks for sharing their triumph with us.

[@SailingTipsCa]

That must have been an amazing journey for the Sailrocket team!!!

[@seadog9534]

Proud to have been part of the Vestas team that built this beaut!

[@SailingTipsCa]

That must have been a cool experience!!!

[@davida1679]

If you live in a sailing town, start walking the docks in the late afternoon/evening and look for teams getting their boat ready to go out for the club/beer can races. In many places it’s on a Wednesday. Don’t worry about getting on the fastest boat right away, start by having fun with a good group of sailors. If you’re 16, respectful and willing to learn, you’ll get a ride! From there, be responsible, show up to all the important events and before you know it you’ll be growing in the sport. This is how I got started back 35 years ago. My first boat was a bunch of bikers, who got together on one of their fathers Catalina 36. Definitely not a race boat but it didn’t take long to move up to the ultralights, and then I was flying across the water.

[@ronmcmartin4513]

@seadog--There are always crazy people with crazy ideas. I want to know, who was the 2nd lunatic who looked at it and said, "Yeah, that'll work!"?

[@philiptorrens2052]

Thanks for this. I'd stubbled across videos of SailRocket years and years ago, but never really understood the tech until your explanation. Fair winds to you!

[@SailingTipsCa]

Glad you enjoyed it!

[@bilharzia]

This is great content. I like easily consumable bites of pure knowledge like this. Keep up the good work!

[@SailingTipsCa]

Thanks - glad you like it!

[@tobuslieven]

I've been fascinated by Sailrocket 2 for ages, and tried to watch all the videos I could about it, but I hadn't understood the mechanics of how it worked until I this video. It's way weirder than I thought it was. Great video!

[@SailingTipsCa]

Thanks so much! I was also disappointed that other videos of Sailrocket didn’t really explain how it worked, so I made this video! Thanks for watching!

[@LoanwordEggcorn]

Yes, but it's really a specialized version/different arrangement of how all sailboats work. It's also very similar to windsurfing (with the rigid wing), which I recall is also very popular (cor setting speed records) in that location in Namibia.

[@brianmgrim]

I think your channel was the one I had mentioned Sailrocket2 as a comment. I had no idea that it was so specialized and had so many shortcomings-they certainly didn’t highlight those in their vid clip. Your knowledge about foil dynamics is quite impressive. Thumbs up!

[@SailingTipsCa]

Yes I did a video called "How Fast Can a Foiling Sailboat Actually Go?!?!" kzbin.info/www/bejne/iYiqc5qIlLOjaac and spoke of the cavitation limit at around 50 knots, and a few people mentioned Sailrocket 2 going faster, so I thought I'd follow up with a Sailrocket video and speak to the limitations and specific conditions it requires. I have an engineering background so am interested in engineering and able to read the papers although I'm not a fluid engineer!

[@petesig93]

It was always clear when Sailrocket 2 was doing its speed runs that it was a starboard-tack only boat, and suited only for flat water, so clearly very limited use. But it does what it was designed for VERY well.

[@florissteenkamp1962]

I am from Walvis Bay and did articles on Sailrocket project for local newspaper. Larse and Helena were on project. Wonderful people and so were the other people who worked on Sailrocket.

[@SailingTipsCa]

How cool that you got to meet and work with them!!!

[@gregepp3082]

The use of a wedge is interesting and something that never crossed my mind. I remember seeing this same concept of the X15. It’s so counter intuitive. Great vid!

[@SailingTipsCa]

It does seem counter-intuitive! Sailrocket used “normal” teardrop foils in early practice but hit the cavitation “glass ceiling”. When they switched to a wedge foil the “glass ceiling” disappeared, but it took much longer to get the boat up to speed because the wedge was much less efficient at lower speeds. Everything is a compromise in sailing!

[@weatheranddarkness]

I wouldn't say it's counterintuitive at all. In both cases you've reached a point where the "suction" side of an airfoil can no longer work. That aspect of a foil only really works when the surrounding pressures can keep the fluid attached. It's that very suction that creates the drop in pressure to below the point at which wants to remain liquid. On the X15 wing, the pressure change is from the supersonic shockwave, and in order to maintain control the thickest part of the wing has to be at the trailing edge.

[@SailingTipsCa]

@@weatheranddarknessIt makes sense when you think about the physics, it’s just that it’s all so ingrained for us to maintain laminar flow around our sails and “slow” foils at all times!

[@dannycalley7777]

G.E. ............I wonder if they have air bleeds to fill that low pressure behind the wedge ?????

[@SailingTipsCa]

@@dannycalley7777 My understanding is that it sucks air down from the surface, so is really.more of a “super ventilating” foil!

[@streetsailor]

Thanks for the clear illustrations!

[@SailingTipsCa]

Glad they made sense!

[@googleyoutubechannel8554]

I think lack of ability to even travel in 2 directions, nevermind turn, definitely puts this in the 'contraption' category

[@SailingTipsCa]

Yes despite being very good at one thing there are definitely some limitations!

[@KlingbergWingMkII]

Amazing! I track this kind of stuff all the time (I'm an aero eng) and I learned new cool stuff today, thanks!

[@SailingTipsCa]

Great to hear!

[@MLambdaman]

Well explained and straight to the point. Good job, sir.

[@SailingTipsCa]

Thanks - glad you liked it!

[@crcpeart]

Great summary ! and Paul Larsen.... brave man to pilot at those speeds!

[@SailingTipsCa]

Yes he was very brave - an accident at those speeds would have serious consequences!!!

[@jonathanlevine8497]

As a speed sailor myself (TriFoiler #23 "Unfair Advantage"), I've been watching Sailrocket since the beginning and admire how fabulously bonkers it is. I'm glad you touched on the (obvious to anyone paying attention) one-tack limitation - scream down, tow it back. Great little vid.

[@SailingTipsCa]

Glad you liked it! I couldn't help but look up your boat and it looks pretty cool too!

[@LoanwordEggcorn]

@@SailingTipsCa The Hobie TriFoilers were amazing. It's kind of sad that they don't have many successors/imitators.

[@SailingTipsCa]

@@LoanwordEggcorn Yes creating a small foiler for the "masses" is a bit of a challenge! I think there have been some decent attempts with the Waszp, UFO, and Stunt S2, but around here (Pacific Northwest) I see mostly foiling kiteboards.

[@LoanwordEggcorn]

@@SailingTipsCa The advantage of the Hobie TriFoiler is that it's probably more stable and relatively drier than a MOTH, etc. It's more like a foiling regular small multihull and not as much of an almost windsurfing/kiting/dinghy type wet experience. Hopefully it also spends much less time broached or capsized.

[@nigeldawson5960]

Dude, excellent explainer. Thanks. I learned something.

[@SailingTipsCa]

Excellent - the goal of the channel is to help people learn about sailing so glad to hear it’s working!!!

[@gefginn3699]

Great post my friend. Very interesting. 🌞🌴⛵️

[@SailingTipsCa]

Thanks so much!!!

[@LoanwordEggcorn]

Thanks for another wonderfully clear explanation. For the relatively static conditions there, one could have a teardrop ladder foil above the cavitating foil to get up to speed sooner. Might cause some drag in wave crests though.

[@SailingTipsCa]

Good eye! I'm pretty sure I've seen some Sailrocket foil photos that do show a sub-cavitating lifting foil section above the cavitating foil for this exact purpose!

[@LoanwordEggcorn]

@@SailingTipsCa Yes, and I may have been vaguely remembering this when when I looked at Sailrocket many years ago. Ladder foils were pretty common in the early days of hydrofoils, but have pros and cons, like anything else.

[@TheSaltyAdmiral]

As a Norwegian I'm honour bound to inform the world that Vestas is a Norwegian company. That is all, carry on.

[@SailingTipsCa]

That’s interesting - aren’t they headquartered in Aarhus Denmark? I could be wrong though!!!

[@philippesails4973]

Great video, no BS, facts bringing an overview on a short format!

[@SailingTipsCa]

Thanks - that was the intent!!!

[@pearpo]

The most fun on earth is sailing on foil. Interesting design, thanks for description.

[@SailingTipsCa]

Glad you liked it! Do you kite foil or on another kind of boat?

[@pearpo]

Modified Hobie my favorite breeze ❤️ Sailing on several lettered heavy scows that flew over the water on a side dagger were earlier experiences of “flying Dutch” ☺️ What about you? What do you get out on?

[@SailingTipsCa]

@@pearpo Sounds like fun! I have a non-foiling F-82R trimaran that moves along pretty well! The breeze around here is too inconsistent (i.e. light) for foiling to really pay off…

[@NICOLAS25478]

Very correct explanations. I was at the Christianing of the SR2 in Cowes. When i saw the foil, i said; no way. But Paul Larson tried to explain it to me for the first time then. Creasy stuff.

[@SailingTipsCa]

That must have been cool to see before she was shipped off to Namibia!

[@ieism1]

Thanks for a great explainer!

[@SailingTipsCa]

Glad you liked it!

[@thomasautos36]

Thanks for the explanation. Always wanted to know how it works

[@SailingTipsCa]

I think it’s pretty ingenious to use a tensioning force instead of ballast!

[@rydenkaye9735]

You should do a video on the attempts to beat sailrocket by syroco and sp80, or others if you can find them. The concept of force alignment is clearly present in their designs, but with a kite and downward foil instead of sail

[@SailingTipsCa]

Good idea! Paul Larsen (Sailrocket 2 skipper/pilot/astronaut) speculated that the Sailrocket 2 record would be most likely be broken by a kite-driven tension device!

[@BradBo1140]

You ain’t kidding, super cool!

[@SailingTipsCa]

Probably also slightly terrifying to sail it that fast!!!

[@ddnorth65]

Excellent, concise description of the technology! You should teach a master class on technology video production !

[@SailingTipsCa]

Thanks for your kind words! I get lots of practice explaining things to my (non-technical) wife!!!

[@JoyriderTV]

Thanks for such a great explanation!⛵⛵⛵🚀

[@SailingTipsCa]

Glad you liked it!

[@DumbledoreMcCracken]

Thank you for an excellent video.

[@SailingTipsCa]

Glad you liked it!

[@jamesaron1967]

Excellent explanation on an otherwise arcane extreme sailing craft.

[@SailingTipsCa]

Glad you liked it!

[@gregripp]

Windsurfers and kiteboarders is this principle but use bodyweight to keep from lifting off. Sometimes you are just riding the fin! It's a blast! Thanks for the video and keep up the good work.

[@SailingTipsCa]

Sounds like so much fun!!!

[@natkingcol909]

That boat is insane.... The driver must have been terrified!

[@SailingTipsCa]

I suspect he might have emptied his drawers after that record run!!!

[@markhuebner7580]

Beautiful! Limited current application, but technology marches on!

[@SailingTipsCa]

It’s a bit niche but very cool!!!

[@billhanna8838]

Always wondered how they got over the cavitation bug , Well explained Thanks .

[@SailingTipsCa]

Glad you liked it!

[@PorkChopXpress4385]

Amazing video. Great job sir!

[@SailingTipsCa]

Thanks for your kind words - glad you liked it!

[@PorkChopXpress4385]

@@SailingTipsCa I believe Einstein said true genuis is explaining something incredibly complex in a way that everyone can understand. Nailed it

[@SailingTipsCa]

@@PorkChopXpress4385 Wow best compliment ever!!!

[@PorkChopXpress4385]

@@SailingTipsCa just had to come back to this one more time. I firmly believe the education system could be transformed with the method of teaching you used. There is a potential to convey so much information in a short period of time if done correctly. It is my opinion that you did it correctly!

[@SailingTipsCa]

@@PorkChopXpress4385 Maybe it would be more fun and engaging for the kids too! Any suggestions for other interesting sailing-related topics?

[@genius1a]

Excellent and compact explanation! I'd say as much as this boat is just for making a speed record run - it shows and extends the technological barriers, that have been reached when using foils at speed. Maybe in 20 years someone will build upon those insights and be able to build an even faster sailing boat with new ideas. Or a boat that can make use of this technology, but designed to be a more practical multi directional sailing vessel.

[@SailingTipsCa]

Sailrocket definitely pushed the limits but had to make some practical compromises to get there! The more recent focus has been to use foils to achieve higher averages speeds in moderate conditions, rather than top-end speed, as explained in this video: How Fast Can a Foiling Sailboat Actually Go?!?!? kzbin.info/www/bejne/iYiqc5qIlLOjaac

[@aaronredbaron]

Awesome! I worked with a team who built an airship that uses a vertical dual foil design, it's called the Windcrafter Carangifoil. It's my dream to see airships sail the sky!

[@SailingTipsCa]

That must have been a cool job!!!

[@aaronredbaron]

@@SailingTipsCa we never found enough funding to build manned versions, but I experienced it working with several radio controlled models, in the wind. There is a patent on it, but it is going into the public domain this next spring. Would love to discuss the benefits of vertical airships if you want, at this point we would just love to see a manned version fly someday!

[@GG-zh6yp]

very cool - bring on the super-cavitation era!!

[@SailingTipsCa]

Exactly! Some say they’re not good in light air though ;-)

[@Nedbruce]

Enjoying your videos, thank you. Question Australia 2 won the Americas cup in 1983 with the wing keel after the Americans had over 130 years. Did this design help in the development of foiling as it, too, was relying on Lift, one of the best yachting stories ever!!

[@SailingTipsCa]

Excellent question - that was amazing when Australia 2 won the cup and the NYYC had to figure out how to remove it from their "permanent" cabinet! It would be interesting to talk to Australia 2's design team, but I suspect their revolutionary winged keel worked in a manner similar to modern airliner winglets (en.wikipedia.org/wiki/Wingtip_device) to increase the lift vs. drag ratio of the keel by reducing the negative effects of the tip vortex.

[@craigruchman7007]

Super informative

[@SailingTipsCa]

Glad you liked it!

[@ElementofKindness]

65 knots on water! Man! That's cookin' even for a powerboat!

[@SailingTipsCa]

I know - good to wear brown underwear when going that fast!

[@lavaljeantet]

Yes for the picture you indicated... and the funny anecdote is THAT THIS PARAVANE HAS BEEN SHORTENED progressively with an electric saw ON TO seek empirically for the optimum area, a figure which is nearly impossible find by CFD

[@SailingTipsCa]

LOL I know! I think they also tried a couple variations of the wedge-shaped design.

[@GarretKrampe]

Yeah good analysis .. well done.

[@SailingTipsCa]

Thanks - glad you liked it!

[@fonwoolridge]

Cool! Good explanations too!

[@SailingTipsCa]

I think it’s a pretty cool boat, and glad you liked the video too!

[@hugogreen13]

Any one who has windsurfing experience will know about cavitation(spin out) . And at much lower speeds than referred to here. So it’s interesting that these foiling yatchts seem to have pushed the boundaries somewhat

[@SailingTipsCa]

Sometimes at lower speeds people will experience foil ventilation, which happens when air gets sucked down the foil and it loses its “grip” on the water. It’s technically not cavitation but often called that - could this be it?

[@Legominder]

Walvis Bay! My old home. Didn't expect that😎

[@SailingTipsCa]

Cool - were you there when Sailrocket set the record?

[@DIYNauticalDream]

Thanks for the detailed explanation. I was wondering how it was able to sail so fast and still stay hooked on the water. It's not very practical since it's limited to only one direction.

[@SailingTipsCa]

Glad you liked it! No not very practical but still cool!

[@geoffmcbroom5302]

I suspect practicality was of little concern in the design and development of Larson's Sailrocket - they wanted to get the world sailing speed record, which they did. A brilliant achievement.

[@SailingTipsCa]

@@geoffmcbroom5302 I completely agree!!!

[@XB10001]

Very ingenious!

[@SailingTipsCa]

I agree!!!

[@leofriedwald9901]

Love your videos, but can you include more data on the wind speed and sea state etc at the time these records were set? Thanks, and keep up the good work 🙂

[@SailingTipsCa]

Yes should have included that! Sailrocket 2 broke the 500 and nautical mile records at Walvis Bay in November 2012, with the wind at 25-30 knots. The sailing area is in the lee of a sand bar so sea state is negligible, hence the location. Hope this helps!

[@bob456fk6]

Very interesting. How fast does (did) an ordinary sailing vessel go with the wind ? How fast could it go against the wind?

[@SailingTipsCa]

The fastest point of sail for any boat is across the wind, and fast non-foiling monohulls can sail at speeds approaching wind speed up until they get to their hull speed, then it takes much more effort to go faster. A fast non-foiling multihull can do 1.2 times wind speed, and foiling boats like those in the SailGP and America’s Cup can do 2-3 times the wind speed!

[@PeterJames143]

Thanks. Sailing is so complicated.

[@SailingTipsCa]

Yes it is, and the constant learning required makes it very interesting IMHO!

[@davemason6501]

Didn't realize the foils cavitated. I thought the speed limit was drag like on an iceboat. The Sailrocket is the latest in a line of record breaker that could only sail on one tack. Remember the 2 Crossbows, and Slingshot? Been enjoying your videos since KZbin brought them to my attention a few days ago.

[@SailingTipsCa]

Sailing fast is all about lift versus drag and the drag can come from lots of places - hull, foils, sails themselves! Glad you’re enjoying the videos!

[@rhett7716]

@@SailingTipsCa hmmm im surprised that they cavitate. so is that a limiting factor with plane wings too?? is it an opposite force the foil is applying against the sail or is it resistance ?

[@iansmith6728]

@@rhett7716 You might find the videos of the design of the SR71 Blackbird very interesting. If you find the right one it will go some way to answer your question. Inspiring engineering.

[@WouterHalswijk]

Very nice and informative video, I had no idea this negative lift hydrofoil principle was used! Only comment: it's not air that fills a cavitation bubble but (low pressure) water vapor. If there is air, it must be an active bleed system.

[@SailingTipsCa]

In this particular case it’s a combination of water vapour from cavitation and air sucked down the from the surface, so really more of a “superventilating” foil!

[@nicholasfulford6753]

It advances engineering and helps push the limits of what was thought possible. That is useful. Whether it leads to practical improvements in sailing speeds is another question. (In this case, probably not due to all the limitations described. Still, it is cool as hell.)

[@KlingbergWingMkII]

Actually, it is a really important result. It clearly shows the benefits to be gained if one can reduce the amount of cavitation on regular foil boats. This is akin to all the work that has been done on airliner design at transonic speeds to reduce fuel consumption (I used to work at Boeing). Trip strips anyone?

[@SailingTipsCa]

@@KlingbergWingMkII In my mind it is akin to transonic transition although the mechanism is different.

[@DonTruman]

Interesting. And glad it's demoted in significance, given how it requires such rare and specialized conditions to function.

[@SailingTipsCa]

It also shows how much specialization is required to get above the ~50 knot cavitation limit!

[@HakureiReimuOfficial]

Amazing stuff. It's definitely a boat though, it's a sea-going vessel, it doesn't fly or ride on land, and a sailboat since it uses the wind to power itself. You wouldn't call a land speed drag car "not a car" because it looks weird, it'll always look weird because speed requires such sacrifices. Also I'd love a go at it, it looks terrifyingly fun!

[@SailingTipsCa]

I think the speed record applies to “sailing craft” which includes boats, wind surfers and kite surfers. I agree that it would be slightly terrifying!

[@HakureiReimuOfficial]

@@SailingTipsCa that makes sense too, actually

[@garyt3hsna1l82]

its an incredible design to see in motion almost as incredible as its list of limitations.

[@SailingTipsCa]

They say everything in sailing is a compromise and this is no exception!

[@bobboberson2024]

Very cool!

[@SailingTipsCa]

I agree!!!

[@AdventureDriver]

I did some windsurfing at Walvis bay, it's fantastic!

[@SailingTipsCa]

That must have been a cool experience!

[@AdventureDriver]

@@SailingTipsCa yeah; flat water, blistering wind, sunny and seals as company.

[@SailingTipsCa]

@@AdventureDriver It would be an amazing experience!

[@whoisjohngalt-hg5us]

For those interested check out the Hudson River Ice Yachts..... phenomenal speed at the start of the 20th Century pardon the pun they blew me away. Congrats on a great channel.

[@SailingTipsCa]

Ice boats are simultaneously amazing and terrifying!!! Glad you like the channel!

[@AntimatePcCustom]

as a dane living near Vestas HQ and even been part of making parts for vestas windmills. im a little proud 😁

[@SailingTipsCa]

Very cool - they make some great windmills!!!

[@JxH]

I've done about 140 kts on water (piston engine powered, not wind powered). It was my neighbour's floatplane, where he performed an extended touch-and-go at fairly high speed along a nearby lake. The speed was about 140 kts indicated. Then he pushed the throttle forward, accelerated to a higher speed (not sure how fast), and then pulled up and took off. Many of the fastest boats on Earth are just floatplanes fooling around.

[@SailingTipsCa]

The unlimited hydroplanes are pretty fast too!!!

[@olivierdamiron7279]

To this day the most amazing design. Many want to break this record, and it is going to be very difficult.

[@SailingTipsCa]

I know, and Sailrocket is only 275 kg / 600 lbs so hard to imagine making it much lighter too!

[@rhett7716]

@@SailingTipsCa they have to figure a sail with less drag 🤔

[@milesmoore8705]

SailGP Team France hit almost 54 knots. Pretty amazing.

[@SailingTipsCa]

I know! Their foils must have been cavititating like crazy!!!

[@gregparrott]

Very interesting. I've never even heard of the 'SailRocket', or the concept of 'Super Cavitation'. Perhaps in a few years, someone will figure out how to apply these concepts in rougher waters and arbitrary courses

[@SailingTipsCa]

Yes it will be interesting to see if somebody can figure out how to build a foil that is efficient in more wind ranges!

[@scheimong]

Supercavitation is super cool. And it's actually used in practice too. Look up the Shkval. It's crazy rocket-powered Russian torpedo that does a ridiculous 200kts underwater.

[@SailingTipsCa]

Yes the torpedo application is is a big one for military use!!!

[@iNcog_AoE]

I was a ramp agent around private jet for about 5 years. I always noticed that some of the jets had square trailing edges on their wings, but I was never able to figure out why or find anyone who knew why. It bugged me for years. Thanks to this video, I suspect that the big jets (think Gulfstream) exploit a super cavitating foil as well. This video was an epiphany to me. Thank you for this upload.

[@SailingTipsCa]

Aeronautic engineers apply all kinds of tricks! Glad you liked the video!

[@Your_Paramour]

cavitation cannot occur in air because air is already vaporised.

[@ernestoherreralegorreta137]

Sailrocket's supercavitating foil reminds me of the North American X-15 rocket plane's supercavitating vertical stabilizer. Although also unable to fly an arbitrary course and was certainly not "particulary practical", the X-15 is still the fastest airplane ever flown nevertheless.

[@SailingTipsCa]

Yes I think there are lots of parallels with experimental high-speed flight!

[@jimbo92107]

How about a rotating pizza cutter blade for the hydroplane? That way the blade would rotate at the same speed as the water, so cavitation would be eliminated. Then you could go as fast as Sailrocket 2, but with a normal hydroplane setup. Tip: Don't touch the blade...

[@SailingTipsCa]

Interesting idea - I agree that touching the blade would not be recommended!!!

[@vndk36]

Hello, great video about a unconventional way of using foils! Their is also now, SP80 and Siroco sail teams that are trying to break this speed record with 2 very different approaches if you want to have a look

[@SailingTipsCa]

Yes definitely an exciting time with different groups going for the record!

[@tomedom5107]

'Maybe not even a boat'? That's what the lead mine sailors used to say about multihulls. Maybe some still do.... as they get lapped. But otherwise a clear explanation. What you didn't mention is that hydroplanes can go much faster than foils and Sailrocket still relies on them for starting flotation, initial speed-up and finally for fore/aft stability. (The speed record for power craft is all about hydroplanes). But, like the L-foil they don't at all like waves and the faster they go the more that is true. Note also that the windsurfer record is done in 'The French Trench' and is also a one tack wonder, even if the windsurfers themselves can sail on the other tack. AND they do not use lifting foils, they sail as a hydroplane.

[@SailingTipsCa]

The "maybe not even a boat" comment was related to Sailrocket's inability to sail an arbitrary course, which drastically limits its usefulness. Interesting points on hydroplanes! Windsurfers which are harnessing an external energy source (i.e. the wind) are also using an underwater foil to translate the wind power into forward motion, which is also susceptible to the cavitation problem, which probably explains why windsurfers are also susceptible to the cavitation barrier and also haven't yet gone much past ~50 knots. All hydroplanes that can go substantially faster than ~50 knots have an internal energy source (e.g. a jet turbine, piston engine) and typically have super-cavitating foils (e.g. propellers, rudders).

[@TheAussieLeo]

Using inefficiency to overcome efficiency problems. What a great design.

[@SailingTipsCa]

Interesting way of looking at it!

[@TheZoePath]

How did they even imagine that design?!? It seems counterintuitive at so many levels.

[@SailingTipsCa]

I think the initial design idea was conceived by Bernard Smith in the 1960s but it took several decades before modern materials and design enabled it to become a reality! Check out the Sailrocket site for more details: www.sailrocket.com/node/259

[@TornadoCAN99]

Land speed sailing record is currently about 120 mph (105 Kts). So it would appear the water interface is still the limiting factor here, not the rig.

[@SailingTipsCa]

Yes drag / friction with the water is far greater than wheels on land or blades on ice, so definitely the limiting factor, even with foils!

[@lachlanhines7644]

The land speed record for cars is currently 760mph with at least 3 current project aiming for 1000mph. The water speed record is 317.5mph, and it hasn't been broken since 1978 because people keep dying trying, though there at at least 6 current WSR projects, including the current LSR holders.

[@malloott]

The "air" behind the hypercavitating foil is a vacuum with low pressure steam and gasses dissolved in the water.

[@SailingTipsCa]

There’s another viewer that worked on the Sailrocket and confirmed in another comment that it’s really a “hyperventilating” foil which would combine steam and gasses with surface air.

[@neilcam]

. Most speed records require the competitor to complete the course in 2 directions (i.e. there and back), the fact that Sailrocket 2 can only go in one direction, to my mind, completely invalidates the record. It's a very interesting contraption, but not a record setter to my mind. Great explanation on the foils though.

[@SailingTipsCa]

Yes with land-based records they like to have you run in two directions to “erase” the effects of the wind, but with sailing records you’re really trying to harness the wind to the greatest degree. I agree it would be far more practical if it could sail an arbitrary course!

[@timonix2]

I wonder if a conventional hydrofoil could beat the cavitation barrier by changing the shape of the foil while moving

[@SailingTipsCa]

Yes that would be really cool - like an airplane wing! The engineering challenge is that foils are comparatively small and very highly loaded so not much room inside for what would need to be some very strong actuators!

[@feedingravens]

So you run into similiarly weird issues like RC gliders. There the speed record is in the meantime 882 kpb (548 mph). So you are as fast as a jet and get near the sound barrier. And that means that you run into compressibility, that in some parts of the wing the air is accelerated to supersonic, which gives a shock wave, causes the airflow to delaminate, the lift to implode and drag to explode. So the ones that "are in the scene" say that to get faster, they would have to switch to transonic airfoils, that are optimized to minimize this shockwave effect of local supersonic airflow. But they - surprise! - are bad at low airspeeds, where you need lift. They are usually very thin with a sharp leading edge (and so only good for a VERY small angle of attack range).

[@SailingTipsCa]

Wow that’s fast for an RC glider!!! Yes the similarities are interesting with efficient (high lift/low drag) foils having “speed limits” which require a different engineering solution to go faster, and that solution is very inefficient at lower speeds! Ideally one would have transforming foil shapes but that’s also very hard in underwater foils because they are very heavily loaded as compared to airplane wings, being much smaller because water is so much denser.

[@shaunybonny688]

Great video. X-15 had wedge shaped airfoils. Kind of an interesting coincidence

[@SailingTipsCa]

Yes I think it’s a known technique for creating usable foils above ~50 knots!

[@shaunybonny688]

@@SailingTipsCa I was referring to the X-plane, manned rocket propelled plane that went almost 7 times the speed of sound

[@SailingTipsCa]

@@shaunybonny688 Gotcha - thanks for clarifying!

[@stahlbergpatreon6062]

Interesting. Would it work to pump air down through the foil and out through a 'flap' that only opens above certain speeds? Airplanes have a similar problem, they use variable geometry to increase speeds

[@SailingTipsCa]

The use of pressurised air is also seen in supercavitating torpedoes! navalpost.com/a-gamechanger-weapon-supercavitating-torpedo/ Variable geometry foils is another interesting idea, but water is about 800 times more dense than air, so foils are much smaller and have much higher load factors than airplane wings, so there's not as much space inside for the the gadgetry!

[@kaeolandon-lane3429]

Great video. Waiting for your channel to blow up. Constructive criticism: leave a few more seconds on the end screen, I barely had time to see what the next video was when you said "watch this next video".

[@SailingTipsCa]

Glad you liked it! Thanks for the suggesting regarding the end screen!

[@P8qzxnxfP85xZ2H3wDRV]

But does it really need flat water? We could just make it bigger and the size of the waves would shrink in relation to the size of the foil.

[@SailingTipsCa]

The Sailrocket was designed to fit into a standard 40’ shipping container to make it easier to transport from the manufacturing site to the sailing site. Making it bigger would enable it to handle bigger waves, but still probably not the waves you’d typically encounter in 30 knots of wind in the open ocean. Deliveries would also be much more difficult!

[@uuzd4s]

Pretty Impressive !

[@SailingTipsCa]

I agree - an amazing accomplishment!!!

[@uuzd4s]

@@SailingTipsCa I fly Radio Control Gliders and getting energy from the wind hasn't all been figured out yet. You want to be amazed, do a Yt search for Dynamic Soaring vid's. These R/C gliders take up to 40g's and do speeds 8 x faster than the prevailing wind. It was discovered by a Lockheed Martin "Skunkworks" engineer by accident when he flew over the ridge top into the swirling wind on the back side of the hill and came out much faster than the wind he was getting lift from on the front side. I went to a Dynamic Soaring event on the coast of Oregon and watched them hit 250mph in a 23 mph wind.

[@SailingTipsCa]

@@uuzd4s Others have mentioned dynamic soaring as well - I’m still trying to wrap my head around it!!!

[@uuzd4s]

@@SailingTipsCa Hadn't done so in a while so I just did a YT search on Dynamic soaring. They just hit 548mph with sustained speeds over 500mph on a 7ft wingspan R/C Glider. The prevailing winds were around 35mph coming up the hill. Most the video doesn't follow a Glider that well at those speeds w/ a handheld camera but there's some of it good enough to WoW ya. Anyways, just more expensive toys to play with I guess. Take Care.

[@SailingTipsCa]

@@uuzd4s That’s amazing - I’ll look that up thanks!!!

[@UselessHumanBeing]

Super cool

[@SailingTipsCa]

I agree!!!

[@AnvilAirsoftTV]

Makes me wonder if a blown flap could do a similar job in a AC or Sail GP foiling boat above the 50 knot barrier

[@SailingTipsCa]

Like a jettisoned flap? The main issue would be that the supercavitating foil is very inefficient at lower speeds so you'd have to stay above 50 knots which would be hard, otherwise sub-cavitating foils will get you there faster with higher average speeds.

[@user-dg5jt5mf8b]

Cool, way cool... ❤❤❤ 😊

[@SailingTipsCa]

I agree!

[@fboomerang]

Seems like a two stage foil is in order, tradiional foil to lift the craft out of the water and wedge for very high speeds. Perhaps one of each on a pair of carbon booms.

[@SailingTipsCa]

Yes that would be really slick!

[@PaulStClair-or3gj]

Could a large version of this carry a load viable enough for industrial transport.. l wonder. (⛵⚓ I do have a great knowledge of ocean yachting. )

[@SailingTipsCa]

Foiling boats are very weight sensitive so you’d be limited to hauling things like feathers and helium balloons!

[@michaelbaker691]

Please forgive my ignorance but I just watched the sail gp in Great Britain. There they set a speed record of over 90knts. What's the difference in speed measurement between the two?

[@casonmartz6144]

That likely was 90 km/h, not kts. Recently SailGP’s measurements have been in km/h, not knots. Franc actually hit 99.9 km/h just a month ago if I recall correctly.

[@casonmartz6144]

*France

[@SailingTipsCa]

Yes I think you might be referring to the speed records recently set in France measured in km/h sailgp.com/news/22/france-speed-record-saint-tropez/ where the French boat hit 99.94 km/h which is just under 54 knots. I think that was also instantaneous and not over any record qualifying distance. They measure in km/h presumably because more people relate to it than knots, but why sailors use knots is a good topic for another video! To convert between them 1 knot is 1.852 km/h.

[@JimP226]

Amazing the Vestas team managed to accomplish this without destroying their boat on a well charted reef or ploughing over a fishing boat killing one of the fishermen. Perseverance at its finest.

[@SailingTipsCa]

Yes, hats off to Paul Larsen and his team!

[@lh9135]

The competition is continuiing with SP80 (Switzerland) and Syroco (France) !

[@SailingTipsCa]

I know - it will be exciting to see how this plays out!!!

[@TommyApel]

Regardless of the limitations of the design, the fact that it can get to 65kt is impressive for a sail boat, it's almost powerboat terretory.

[@SailingTipsCa]

Yes and there are many powerboats that can’t approach Sailrocket’s speeds!

[@pontuswendt2486]

AMAZINGNES!!!

[@SailingTipsCa]

I agree!!!

[@patriciapiper6294]

rocket is right!!! 🗼 It wont be long before you can go back and forth!!! That can't be a long lived problem for You folks!!!!🙏all my love! ❤Patricia

[@SailingTipsCa]

There are some asymmetric boats called proas that look kind of like this, but I haven’t seen a foiling one yet!