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. 👍
@@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.
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!
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.
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.
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!
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!
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!
Yes I did a video called "How Fast Can a Foiling Sailboat Actually Go?!?!" th-cam.com/video/SWGBgR_Np3E/w-d-xo.html 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!
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.
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!
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!
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.
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.
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.
@@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.
@@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.
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!
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!
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.
@@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!
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
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!
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.
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!
@@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.
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......
Wait the moment i look at the foil configuration of the boat my immediate thought was transonic and supersonic airfoils from the aviation side, X15 also had a wedge rudder because normal rudder wouldn't work at hypersonics speeds. Facinating.
Yes "fluids" follow different rules at different speeds! Of course with water the changeover is at a lower speed because it's 800 times more dense than air.
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.
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.
The super cavitating foil with the wedge shape is similar to the tail on the X-15 which also used a wedge shape as opposed to a tear-drop shape -- and for a similar reason.
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.
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.
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.
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?
@@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…
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.
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?!?!? th-cam.com/video/SWGBgR_Np3E/w-d-xo.html
3:15 of flawless delivery. Guy, you might be the best I´ve seen. You got right to it and there were no questions left unanswered. Well maybe, how much is Vestas spending to achieve the record? Answer, if a wind turbine/wind farm multi-national can not win...then who?
Thanks for the kind words! I have no idea how much the Sailrocket project cost, nor what percentage of it was covered by Vestas, but I’ll keep my eyes and ears open!
@@sneescampers Yes that’s why I didn’t include Sailrocket in this video: How Fast Can a Foiling Sailboat Actually Go?!?!? th-cam.com/video/SWGBgR_Np3E/w-d-xo.html I think Sailrocket is cool but also very niche!
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 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!
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
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?
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
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 TH-cam brought them to my attention a few days ago.
@@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 ?
@@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.
@@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!
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.)
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?
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!!
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.
Super interesting. Looking at the realistic purpose and usability in real life it becomes clear that there is hardly any application that these boats can be used commercially. There is no way this system can work in waves. In the end its a very isolated field of usage.
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.
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!
Everything you said about Sail Rocket are fair points. But I disagree with you about not mentioning Sail Rocket in a discussion about fast sailboats, for several reasons. First, Paul Larsen's team did this record breaking work more than 10 years ago, and to my knowledge, their outright sailing speed record is not yet being threatened. What they accomplished in basically a small shed, and a shoe-string budget, is a testimony to hard-headed commitment. It's nothing short of astonishing. Second , the fundamental R&D that went into designing, building, and testing sail-rocket is classic Wright-brothers style of engineering. My hat's off to this crew. Finally, Sail Rocket achieved a peak instantaneous speed of 68.33 knots....this in a sail driven craft. At the time, this simply defies belief. Around the time of the Sail Rocket record runs, I watched a video piece on the kite surfers at Luderitz making speed runs in their specially dug trench in the sand. As one kite boarder packed up his rig in the trunk of his car, he smuggly said "let's see sail rocket do that". A bystander overheard the comment and shot back: "OK, now let's see you put the trench in your trunk as well." Touche. Point is, early advancements in sailing speed records necessarily occur within the limitations of then existing engineering limits, designs, and materials. Sailing faster yet is the scientific process at work.
I agree that the Sailrocket project produced an amazing result on a tiny budget compared to other campaigns! My comments about it being a boat or not are related to the fact that it can only sail on one tack and one point of sail i.e. it can’t sail an arbitrary course. Still an amazing achievement in my mind though!!!
@@SailingTipsCa Yehp, that's fair. But Sailrocket also overcame fundamental limits to the then-known design paradigms and challenges, pointing the way for others to follow. 11 years later, still an astonishing accomplishment.
@@vermontsownboy6957 Yes first sailing vessel with super-ventilating/cavitating foils that I’m aware of!!! I think Syroco is using some of the same concepts but haven’t pulled it all together yet…
. 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.
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!
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.
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!
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
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.
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!
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".
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.
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.
All boats are a compromise. This boat makes a lot of compromise's to achieve the speeds it does. The biggest compromise it makes is practicality... This is about as practical as converting a Trimaran into a wing in ground affect. Thanks for the video.
@@SailingTipsCa It's definitely pushing the limits of something.. 🙂 My wife and I have sailed the coast of Alaska for 20+ years for months at a time. I am fine with sailing at 5-6 knots and watching the scenery go by. My priority is a safe, seaworthy boat not speed. That is the compromise I make when buying a boat. Last thing I want is to have the damn thing sink out from under us 100 miles from anywhere.. I wouldn't mind owning a faster boat as long as it isn't a compromise in safety and seaworthiness. Thanks for the reply! 🙂
@@SailingTipsCa Turning a Trimaran into a wing in ground effect. Now that would be an impressive engineering feat. Especially if you could accomplish it with sails instead of a motor. Hmm sounds like I found a winter project.. 🙂
My simple question regarding Sailrocket 2 is why have they not tweeked her and gone out again to squeeze another few knots? Would love to see her out once a year in Walvis. It's been 12 long years since the record was set. Where is all the competition as well?
I suspect they were probably exhausted both financially, emotionally, and physically at the time, and having smashed the record by such a huge margin the team members probably disbanded to pursue other opportunities that would have been knocking down their doors at the time. There is however another project actively chasing their record: syro.co/en/speed-record/
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.
'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.
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).
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
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.
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 🙂
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!
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...
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. 👍
Well said - I totally agree!!!
It is certainly uber cool, and just the toy for some rich, sail enthusiast, Namibian, who has everything else already
@@alexanderSydneyOz And it does keep the rest of us (non-rich) entertained!
@@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.
That pass reminds me of the olden days land and water speed runs using engines, just sittin there ready to die.
This channel is criminally underrated. Great job.
Thanks - glad you like it!!!
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!
That sounds like lots of fun - I agree!!!
Proud to have been part of the Vestas team that built this beaut!
That must have been a cool experience!!!
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.
@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!"?
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.
That must have been an amazing journey for the Sailrocket team!!!
Great video...informative, to the point, not overly long, and no BS.
That was the idea - glad you liked it!
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!
Glad you enjoyed it!
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!
Thanks so much - glad you liked it!
Yes, this channel is really criminally underrated. Great job.
Thanks so much - glad you like it!!!
This is great content. I like easily consumable bites of pure knowledge like this. Keep up the good work!
Thanks - glad you like it!
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!
Yes I did a video called "How Fast Can a Foiling Sailboat Actually Go?!?!" th-cam.com/video/SWGBgR_Np3E/w-d-xo.html 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!
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.
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!
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!
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.
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.
How cool that you got to meet and work with them!!!
I think lack of ability to even travel in 2 directions, nevermind turn, definitely puts this in the 'contraption' category
Yes despite being very good at one thing there are definitely some limitations!
but if you disqualified that, you would do the same for land speed record holding vehicles. Many designed to point straight on salt flats.
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.
Glad you liked it! I couldn't help but look up your boat and it looks pretty cool too!
@@SailingTipsCa The Hobie TriFoilers were amazing. It's kind of sad that they don't have many successors/imitators.
@@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.
@@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.
"fabulously bonkers" is a nice way of describing it lol
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!
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!
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.
@@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!
G.E. ............I wonder if they have air bleeds to fill that low pressure behind the wedge ?????
@@dannycalley7777 My understanding is that it sucks air down from the surface, so is really.more of a “super ventilating” foil!
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
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!
It may be a one trick pony but man is that a cool trick.
That’s a great way of describing it!!!
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.
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!
@@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.
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......
Thanks so much for your expert insight!!!
THANKS, that is some GOOD insight. Have a nice DAY.
NOW we KNOW
INTERESTING INFORMATION. SPEAK UP, I COULDN'T MAKE OUT SOME OF THAT.
The seemingly RANDOM combination of CAPS and lower CASE above is in FACT a perfect balance THAT HAS achieved THE most AERODYNAMIC TH-cam COMMENT ever.
Great description, I don’t sail but found this fascinating and easily understandable.
Excellent - so glad you enjoyed it and it made sense!!!
Great summary ! and Paul Larsen.... brave man to pilot at those speeds!
Yes he was very brave - an accident at those speeds would have serious consequences!!!
Wait the moment i look at the foil configuration of the boat my immediate thought was transonic and supersonic airfoils from the aviation side, X15 also had a wedge rudder because normal rudder wouldn't work at hypersonics speeds. Facinating.
Yes "fluids" follow different rules at different speeds! Of course with water the changeover is at a lower speed because it's 800 times more dense than air.
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.
That must have been cool to see before she was shipped off to Namibia!
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.
Aeronautic engineers apply all kinds of tricks! Glad you liked the video!
cavitation cannot occur in air because air is already vaporised.
You ain’t kidding, super cool!
Probably also slightly terrifying to sail it that fast!!!
Amazing! I track this kind of stuff all the time (I'm an aero eng) and I learned new cool stuff today, thanks!
Great to hear!
The super cavitating foil with the wedge shape is similar to the tail on the X-15 which also used a wedge shape as opposed to a tear-drop shape -- and for a similar reason.
Yes lots of analogies with the X-15!
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.
Sounds like so much fun!!!
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.
Glad you liked it! No not very practical but still cool!
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.
@@geoffmcbroom5302 I completely agree!!!
The most fun on earth is sailing on foil. Interesting design, thanks for description.
Glad you liked it! Do you kite foil or on another kind of boat?
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?
@@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…
As a Norwegian I'm honour bound to inform the world that Vestas is a Norwegian company.
That is all, carry on.
That’s interesting - aren’t they headquartered in Aarhus Denmark? I could be wrong though!!!
Well explained and straight to the point. Good job, sir.
Thanks - glad you liked it!
Great post my friend. Very interesting. 🌞🌴⛵️
Thanks so much!!!
Always wondered how they got over the cavitation bug , Well explained Thanks .
Glad you liked it!
Excellent, concise description of the technology! You should teach a master class on technology video production !
Thanks for your kind words! I get lots of practice explaining things to my (non-technical) wife!!!
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.
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?!?!? th-cam.com/video/SWGBgR_Np3E/w-d-xo.html
Beautiful! Limited current application, but technology marches on!
It’s a bit niche but very cool!!!
3:15 of flawless delivery. Guy, you might be the best I´ve seen. You got right to it and there were no questions left unanswered. Well maybe, how much is Vestas spending to achieve the record? Answer, if a wind turbine/wind farm multi-national can not win...then who?
Thanks for the kind words! I have no idea how much the Sailrocket project cost, nor what percentage of it was covered by Vestas, but I’ll keep my eyes and ears open!
@@sneescampers Yes that’s why I didn’t include Sailrocket in this video: How Fast Can a Foiling Sailboat Actually Go?!?!?
th-cam.com/video/SWGBgR_Np3E/w-d-xo.html I think Sailrocket is cool but also very niche!
Great video, no BS, facts bringing an overview on a short format!
Thanks - that was the intent!!!
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!
That must have been a cool job!!!
@@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!
That boat is insane.... The driver must have been terrified!
I suspect he might have emptied his drawers after that record run!!!
It's not a sailboat. It's a sea anchored solid wing kite.
LOL that’s a great description!!!
Thanks for the clear illustrations!
Glad they made sense!
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
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?
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
LOL I know! I think they also tried a couple variations of the wedge-shaped design.
65 knots on water! Man! That's cookin' even for a powerboat!
I know - good to wear brown underwear when going that fast!
Thanks for the explanation. Always wanted to know how it works
I think it’s pretty ingenious to use a tensioning force instead of ballast!
Dude, excellent explainer. Thanks. I learned something.
Excellent - the goal of the channel is to help people learn about sailing so glad to hear it’s working!!!
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 TH-cam brought them to my attention a few days ago.
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!
@@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 ?
@@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.
Amazing video. Great job sir!
Thanks for your kind words - glad you liked it!
@@SailingTipsCa I believe Einstein said true genuis is explaining something incredibly complex in a way that everyone can understand. Nailed it
@@PorkChopXpress4385 Wow best compliment ever!!!
@@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!
@@PorkChopXpress4385 Maybe it would be more fun and engaging for the kids too! Any suggestions for other interesting sailing-related topics?
Yeah good analysis .. well done.
Thanks - glad you liked it!
Excellent explanation on an otherwise arcane extreme sailing craft.
Glad you liked it!
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.)
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?
@@KlingbergWingMkII In my mind it is akin to transonic transition although the mechanism is different.
very cool - bring on the super-cavitation era!!
Exactly! Some say they’re not good in light air though ;-)
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!!
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.
To this day the most amazing design. Many want to break this record, and it is going to be very difficult.
I know, and Sailrocket is only 275 kg / 600 lbs so hard to imagine making it much lighter too!
@@SailingTipsCa they have to figure a sail with less drag 🤔
Super interesting. Looking at the realistic purpose and usability in real life it becomes clear that there is hardly any application that these boats can be used commercially. There is no way this system can work in waves. In the end its a very isolated field of usage.
Yes there are only a very few places in earth that this boat can effectively sail! Still cool technology though!
Interesting. And glad it's demoted in significance, given how it requires such rare and specialized conditions to function.
It also shows how much specialization is required to get above the ~50 knot cavitation limit!
SailGP Team France hit almost 54 knots. Pretty amazing.
I know! Their foils must have been cavititating like crazy!!!
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.
Yes I think there are lots of parallels with experimental high-speed flight!
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!
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!
@@SailingTipsCa that makes sense too, actually
Thanks for such a great explanation!⛵⛵⛵🚀
Glad you liked it!
Thanks for a great explainer!
Glad you liked it!
Thanks. Sailing is so complicated.
Yes it is, and the constant learning required makes it very interesting IMHO!
Everything you said about Sail Rocket are fair points. But I disagree with you about not mentioning Sail Rocket in a discussion about fast sailboats, for several reasons. First, Paul Larsen's team did this record breaking work more than 10 years ago, and to my knowledge, their outright sailing speed record is not yet being threatened. What they accomplished in basically a small shed, and a shoe-string budget, is a testimony to hard-headed commitment. It's nothing short of astonishing. Second , the fundamental R&D that went into designing, building, and testing sail-rocket is classic Wright-brothers style of engineering. My hat's off to this crew. Finally, Sail Rocket achieved a peak instantaneous speed of 68.33 knots....this in a sail driven craft. At the time, this simply defies belief.
Around the time of the Sail Rocket record runs, I watched a video piece on the kite surfers at Luderitz making speed runs in their specially dug trench in the sand. As one kite boarder packed up his rig in the trunk of his car, he smuggly said "let's see sail rocket do that". A bystander overheard the comment and shot back: "OK, now let's see you put the trench in your trunk as well." Touche.
Point is, early advancements in sailing speed records necessarily occur within the limitations of then existing engineering limits, designs, and materials. Sailing faster yet is the scientific process at work.
I agree that the Sailrocket project produced an amazing result on a tiny budget compared to other campaigns!
My comments about it being a boat or not are related to the fact that it can only sail on one tack and one point of sail i.e. it can’t sail an arbitrary course.
Still an amazing achievement in my mind though!!!
@@SailingTipsCa Yehp, that's fair. But Sailrocket also overcame fundamental limits to the then-known design paradigms and challenges, pointing the way for others to follow. 11 years later, still an astonishing accomplishment.
@@vermontsownboy6957 Yes first sailing vessel with super-ventilating/cavitating foils that I’m aware of!!! I think Syroco is using some of the same concepts but haven’t pulled it all together yet…
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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.
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!
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.
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!
I bought one of these, sailed across the lake. And now I’m just waiting for the rare westerly wind so I can get it back.
LOL I guess you didn’t pay extra for the tow service option back to the other side?
How did they even imagine that design?!? It seems counterintuitive at so many levels.
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
Walvis Bay! My old home. Didn't expect that😎
Cool - were you there when Sailrocket set the record?
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.
Ice boats are simultaneously amazing and terrifying!!! Glad you like the channel!
The competition is continuiing with SP80 (Switzerland) and Syroco (France) !
I know - it will be exciting to see how this plays out!!!
Thank you for an excellent video.
Glad you liked it!
Look at the shape of the tail fin on a Blackbird SR-22, it has the same wedge shape like the Sailrocket foil !
Interesting observation!
I've said it before and i'll say it again: if I understand even a quarter of what racing sailors do and why I'll be a proud sailor.
LOL lots of “type 2 fun” involved!!!
Very interesting.
How fast does (did) an ordinary sailing vessel go with the wind ?
How fast could it go against the wind?
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!
Great video, thanks
Glad you liked it!
Using inefficiency to overcome efficiency problems. What a great design.
Interesting way of looking at it!
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".
Glad you liked it! Thanks for the suggesting regarding the end screen!
as a dane living near Vestas HQ and even been part of making parts for vestas windmills. im a little proud 😁
Very cool - they make some great windmills!!!
Super informative
Glad you liked it!
Great video.
Glad you enjoyed it!
its an incredible design to see in motion almost as incredible as its list of limitations.
They say everything in sailing is a compromise and this is no exception!
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.
Yes the torpedo application is is a big one for military use!!!
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.
Yes, hats off to Paul Larsen and his team!
60 kts?! SIXTY?! That's insane. I don't care if it's actually not a boat it's still an impressive feat of engineering. 😊
Yes 65.24 to be precise, and the momentary top speed was 68 or something. That’s over 120 km/h!!!
@@SailingTipsCa I believe not every helicopter can go that fast :)
@@getsideways7257 Even a slower helicopter is probably more versatile though!
@@SailingTipsCa True. And either is exceedingly dangerous.
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
There are some asymmetric boats called proas that look kind of like this, but I haven’t seen a foiling one yet!
All boats are a compromise. This boat makes a lot of compromise's to achieve the speeds it does. The biggest compromise it makes is practicality... This is about as practical as converting a Trimaran into a wing in ground affect. Thanks for the video.
Yes all boats are indeed a compromise, especially when pushing the limits of performance!!!
@@SailingTipsCa It's definitely pushing the limits of something.. 🙂 My wife and I have sailed the coast of Alaska for 20+ years for months at a time. I am fine with sailing at 5-6 knots and watching the scenery go by. My priority is a safe, seaworthy boat not speed. That is the compromise I make when buying a boat. Last thing I want is to have the damn thing sink out from under us 100 miles from anywhere.. I wouldn't mind owning a faster boat as long as it isn't a compromise in safety and seaworthiness. Thanks for the reply! 🙂
@@mojoneko8303 Definitely understandable given the remoteness of your sailing area - beautiful place!!!
@@SailingTipsCa Turning a Trimaran into a wing in ground effect. Now that would be an impressive engineering feat. Especially if you could accomplish it with sails instead of a motor. Hmm sounds like I found a winter project.. 🙂
@@mojoneko8303 Yes, and you could make a TH-cam channel!!!
"maybe not even a boat" made me roll
LOL the World Speed Sailing Record Council (WSSRC) cleverly dodges the issue by calling them “sailing craft”!
My simple question regarding Sailrocket 2 is why have they not tweeked her and gone out again to squeeze another few knots?
Would love to see her out once a year in Walvis. It's been 12 long years since the record was set.
Where is all the competition as well?
I suspect they were probably exhausted both financially, emotionally, and physically at the time, and having smashed the record by such a huge margin the team members probably disbanded to pursue other opportunities that would have been knocking down their doors at the time. There is however another project actively chasing their record: syro.co/en/speed-record/
I did some windsurfing at Walvis bay, it's fantastic!
That must have been a cool experience!
@@SailingTipsCa yeah; flat water, blistering wind, sunny and seals as company.
@@AdventureDriver It would be an amazing experience!
The "air" behind the hypercavitating foil is a vacuum with low pressure steam and gasses dissolved in the water.
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.
'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.
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).
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
Yes it will be interesting to see if somebody can figure out how to build a foil that is efficient in more wind ranges!
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
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.
Cool! Good explanations too!
I think it’s a pretty cool boat, and glad you liked the video too!
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 🙂
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!
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...
Interesting idea - I agree that touching the blade would not be recommended!!!
65 knots is crazy fast on water and especially for a sailing vessel.
I know - it must have been frightening to be aboard and piloting that thing!