637 replies to this topic

[Fat Point Jack]

The season begins again!

http://www.sailrocket.com/blogs

[auscat]

This is the one Larso go gettem.

[Mojounwin]

There be some interesting times ahead. Go Team VSR!

Cheers
Mojo

[auscat]

http://www.shackletonepic.com/

Surprised no one has picked up on this yet.Talk about extremes.

Didn't quite get the link right ,check out the crew list.

[Tom Ray]

That's one crazy wing. A picture of it without the top piece:

[auscat]

 314181_10152140956660652_1962767034_n.jpg   159.14K   107 downloads

Larso's 60 knt foil pre baking and finnishing.

[Amati]

Having mulled over the advantages of the segmented wing with bungie cords concept a few years ago, I'm stoked.

Kick ass guys!

[Kenny Dumas]

Averaged 45, peak over 51 knots today in 25 knots of wind with the new foils working well.

[auscat]

http://youtu.be/1mH1bVvIPqY
just another 50 knt run.Very cool

[Amati]

+1

Mr Smith is smiling.

[Tom Ray]

It looks a lot more firmly attached to the water than the last one. Also looks to be capable of more speed.

[Raked aft \\]

They've got to push the power.

Either bigger wing or more wind. Otherwise I think they're maxing out the setup.

[auscat]

Got to with in 1/2 a knot of the record ,c'mon Larsso send it.

[Donjoman]

Nice work!!

[larso]

Sending it as hard as we can! The fact we can handle the boat in 34 knots of wind speaks volumes for the new boat. As mentioned, we shouldn't need that sort of grunt but it's a nice card to pull if you have to. Now we have to do some speed sailing forensics to find out where the 'brick-wall' of drag at 52 knots is coming from. We need sweet release! Video from yesterday coming soon. No sailing today.

[Mojounwin]

It's great to see you guys back out there. I check the updates every morning to see if the mission has been accomplished.

Cheers
Mojo

[larso]

Here's the video from yesterday. http://youtu.be/JBH0J1MyELk
We still have plenty of tricks to play with. Funny that we have tried around 6 different foils of wildly different shapes and sizes on two boat... and always seem to hit the same speed. Need to work this one out!

[Tom Ray]

...Funny that we have tried around 6 different foils of wildly different shapes and sizes on two boat... and always seem to hit the same speed. Need to work this one out!

That wall at around 50 knots may be unrelated to your boat. It's just a wall. Powerboaters notoriously misoverestimate the speed of their craft, but if you actually clock them, you find that exceeding 50 knots is not all that easy. The answer is generally the same as in other speed contests: more power and less weight.

So you need more power! Try to keep it in the water this time! Good luck!

[Amati]

SailRocket is starting to get that hard slapping bounce that hydroplanes get. That's got to be good. Seems hydros go for WIG lift to get out of the the water more than foils, which seem to be used more for tracking?

Wondering about what looks like a fair bit of Aero wetted surface too. Maybe it just takes an oooch to get through that?

Go SailRocket!

[JMD]

Why no windscreen/bubble for the cockpit? You'd think aero drag would be a big deal at those speeds.

[Tom Ray]

Why no windscreen/bubble for the cockpit? You'd think aero drag would be a big deal at those speeds.

I think there's a special hat to take care of that problem.

[larso]

The aero drag is actually a very small part of the equation. Overall this a very aerodynamic package. The whole boat has the equivalent aero drag of a 76cm sphere. Last time, with the first boat, I had the aero helmet angled at 26 degrees to line up with the apparent wind... now we have the whole boat. I do have the windscreen... and back seat hatch cover... and quite a few other little aero add ons but I don't want to damage them or have them interfere with runs whilst we are still looking at the bigger issues. We should have around 100kg of excess thrust at 50 knots (in 26 knots of wind). Something far bigger than aero is holding us back. If it was just aero holding us back then it would also be a bit more progressive. We would see big gains by sailing in more wind as we would get greater power and the apparent wind angle would open up (for the same or boat speed).
We are pretty certain that whatever is holding us back is foil related. We will undertake a process of elimination to find out what it is. we have some handy pressure sensors that are now 'looking' at the rudder to see how that is behaving. It's pretty interesting from our end. Every run holds a world (record) of possibility.

[MR.CLEAN]

Larso can you direct us to a closeup pic of the main foil with the pressure sensors on it?

[JohnMB]

Are you looking at this from a drag vs accelerating force view or are you also looking at the energy balance? If there is a drag 'barrier' there must also be an energy sink where the extra energy is going, have you been able to figure out where that is? It may not help at all, but there may be other different ways to look at the problem which will give some additional insight.

From what you say the change in the foil shape is not making a significant difference to the 50kt barrier is it possible that you are hitting a vibration mode in some other part of the structure which is causing the foil to flutter? Or maybe if the foils all have similar stiffness they all develop a flutter at a similar speed?

[larso]

There is no obvious vibrations on the boat other than when either the rudder or main-foil 'chokes'. They are both basically 'wedge' shaped in that they are sharp at the front and increase to their maximum thickness near the trailing edge. The trailing edge is the fattest part of the foil. We call the back face of the foil the base. It can be thought of like the transom of a planing boat. It is draggy until the flow separates cleanly off the sides of the foil and then it becomes dry. The only way it can create drag is if there is suction acting on that back face. If it is fully ventilated from the surface then there is nearly no drag penalty. If it is cavitating then the whole base is exposed to the full vapour pressure of 18 degree celsius sea water. This will be somewhere near -1 bar or -14psi. Now you wouldn't expect the foil to cavitate right near the surface as ambient air will easily ventilate down shallow depths... but further down the foil the pressure in the 'base cavity' was expected to drop. The big question was how much would the pressure drop as we went down. Having a 90 degree curved foil added another dimension to how well the foil would ventilate. The base cavity is always being shed off the foil as it travels along so the foil needs a constant feed of air from the surface. The water coming off the sides of the foil will be falling into this cavity at 1G... unless they are being sucked in by low pressure in which case they collapse much quicker. Some times this process of choking can be started by spray at the surface. I had it happen a few times with our first attempt at a high speed foil during our last session. I could be travelling at around 50 knots when a harsh, rumbling' sort of sound would come from the main foil. The speed would drop rapidly to around the high 20's. The boat felt like it was being dragged up a concrete ramp on its foils. Later on we worked out that the speed that VSR2 would reach if base cavitating was only in the high 20's. It all sort of made sense. The cavity at the base of the foil had been rapidly pulsing... or gulping air as the base cavity would go from ventilated/ambient pressure to cavitating pressure.
I haven't felt this on the new foil... but suspect that I have on the new rudder. It mostly happens when I bear away... I can feel that rumble through the boat. We will put the pressure sensors on the back face of the rudder to see if this is the case.
The thing is that it seems that the foils are generally very well ventilated down their base. In a funny way this is annoying. I would like to say that this is where we are losing a huge amount of our power. As mentioned, we will look at the rudder and then make a call. Maybe we are losing a good chunk there and the rest is just cumulative. Personally I doubt it... but I want to be sure.
I don't think there are any other vibrations or flutter issues. VSR2 is a pretty smooth ride once I get in by the shore. Anything that would burn off 100kg of thrust would be pretty significant... like the choking was. It's an interesting problem. Whilst we are going well in some respects, we are way off the mark in others i.e. we are easily doing 50 knots... but we should be doing 60. There is a big piece still missing. We will start by looking at the potential big-loss areas and work backwards from there. The rudder could easily be choking as it operates in a relatively dirty area under the front float and behind the forward step. There would be all sorts of spray flying around in there. We will soon know. The sensors will tell us exactly what is going on. If it's not that then we will move back to the main foil. As soon as we know what it is exactly... we should be able to fix it. We still have a few tricks up our sleeve to play with shapes.
I haven't posted any close up pics of the foil as it stands. It's currently being painted and faired one more time outside by Ben. When it's done and the sensors are back on... I'll post something to give you an idea.

[luminary]

why not just lead/embed a ventilation tube from somewhere above the surface to the back/base so that there is always a path for air to get there regardless of shape/localized fluid pressures?

[luminary]

How do you trim the wing when it is behind you and you are looking forward??

[Tom Ray]

There is no obvious vibrations on the boat other than when either the rudder or main-foil 'chokes'. They are both basically 'wedge' shaped in that they are sharp at the front and increase to their maximum thickness near the trailing edge. The trailing edge is the fattest part of the foil....

That seems strange. I almost understood the explanation of how once that back edge is dry, you eliminate some drag. But it still seems strange. Looking forward to the pics!

[larso]

We don't need to run tubes down the back of the foil. If we had a problem that required a tube... it might actually require a big tube as we aren't allowed by the WSSRC rules to force feed air down there using any stored energy. Before you get carried away on alternatives... we have looked at it hard, considered it in all its aspects and then bought expensive sensors to see if it was necessary. At this stage they are telling us it absolutely isn't. We are about to have a look at the rudder which may or may not be a different story due to its messy environment under the front float. Whilst I doubt we will use little tubes to feed air down, we may use channels to ffed clean, spray-free air to the water surface where the rudder enters.
In order to trim the wing I have a Cosworth display in the cockpit that relays information from a little laser sensor in the wing. It tells me what angle the wing is at. In all honesty I now actually look over my left shoulder and see if the wing is sheeted in to the fixed lower section. The fixed lower section is set at the perfect 10 degree angle. When the middle and upper parts align via me sheeting them in, I know I am right. I don't need the display anymore and for the first time during the last run... I set it up to display boatspeed. I want to see 60 on that dial... although it will probably be the last thing I will be looking at. When you see my head looking around at the leeward pod during that last video, I'm actually checking both wing angle and the height at which the pod is balancing out at. I can control both.
If/when I take a passenger, they will be sitting so they face backwards. That is the best way to look to see both the wing and the foil. When we designed the boat we thought it might be easier to sail with two people and that the back seat crew would be sheeting the wing.

[Mojounwin]

Hey Larso,
Now you've had a few runs in the VSR II how difficult do you think it would be for a new skipper to drive? Is it the sort of thing someone with reasonable sailing experience and a bit of guidance could do? It sounds like the start up proceedure is less complex then was thought during the design phase (no swinging the beam etc.)

Cheers
Mojo

[larso]

Hiya Mojo, I hope all is well. I reckon that VSR2 should be pretty easy for someone else to drive. It certainly feels that way to me. On the other hand most skilled bike riders would think it's pretty easy to go out and cane a modern super-bike. The thing is it is pretty easy... but you need to ease yourself into the experience. In many ways there isn't a lot to go wrong at the start and during the run itself. Slowing down requires some confident, positive action. You don't want to hang about with indecision. It's kind of like stopping a car in limited area with your hand brake. Once on the course VSR2 kind of takes care of itself. The steering is very positive and thanks to the work put in by the design team, the boat itself seeks stability... unlike VSR1. I often reflect back on what an unstable beast that one was. I think about how it pretty much went at similar speeds to what VSR2 is doing now... but was always on the edge of flipping out. It really was like flying a plane backwards. I wouldn't have put anyone in that boat in top end conditions. Not because of skills... but because it simply wasn't that safe. In the end I did feel comfortable in it. I would be happy to teach someone to sail the new boat. I would love to stand on the beach for once and watch it go by. I still have no idea what it's like to watch a boat go by at 50 knots. Hopefully we can reach our goals and then I will begin to hand the helm over. The ride in the back seat facing backwards would be awesome. As I write this, Ben is actually starting on making a bigger rear skeg/rudder to make the start up sequence with two people easier. I would love to hear what someone else thinks of driving the boat.

[Raked aft \\]

Larso,

Curious if there has ever been any thought to steering the front pod, once at speed, using an aero type rudder instead of a hydro rudder?

seems to me if she wants to pretty much steer herself, that the drag reduction of a small steering vane in the air would be beneficial over the much higer drag of a water based rudder?

[larso]

Hi Raked Aft, (just back in from an unsuccessful attempt to sail in too light conditions)...we really wanted to do this (use aero steering). We tried it with the first Sailrocket and thought it would be a definite starter on this one. I still think about it now. It seems to have so much going for it. The boats configuration could actually be set up with a little weather helm so that the rudder could be providing thrust instead of almost pure drag. To be honest, I would have to go back through some old files to tell you exactly why we canned it in the end but I do know that we really tried to make it a go'er. I think it came down to a number of things including the need for either too large an air-rudder at low speed or a complicated transition requiring low speed kick up hydro-rudders that could reliably do safe transitions to the air rudder as the apparent wind moves forward at a rapid rate. The air rudder would have to change its angle with the change in apparent wind angle and strength whilst I would also have to be sheeting in the wing and kicking up rudders. It all got a bit messy and complicated. Even then we pushed on with the idea but slowly our persistence started to change the whole shape of the boat just to make it work... whilst there were other gains to be made by ditching it. Another issue was that it was likely that we weren't going to be so locked onto our course as we would be with hydro rudders. This could be dangerous so close to a windward shore with a boat balanced for weather helm. The boat would potentially move/float around a lot more as it orientated itself to the gusts. I do remember that it all got very complicated. We didn't give up on it easily. Like I said, I still think about it. I tell you what, I'll go through it again with the brains trust and try and be more specific.

[Raked aft \\]

Thanks for the reply...

I'm just glad to see one of my whacky ideas isn't so whacky after all.

I get your set up with the built in weather helm and compensate w a aero vane, but i'm not sure that's the best solution.
I would set her up as helm neutral as possible and just steer w the vane.

Here's how i invision it working. In the ramp up, say to 40kts, the hydro rudder is steering and the vane is free wheeling, pointing directly into the apparent. With a flip of one lever, the hydro rudder retracts, or kicks back, and a clutch locks the aero vane into the stearing cables to the cockpit.

As you blast through the 60kt barrier, I would imagine the aero vane response to steering input would be very noticeable!!

[BalticBandit]

You mentioned that aero drag isn't an issue and that your net drag is that of a 76cm sphere. That may be true in the linear flow case, but have you looked at the induced drag from things like vortices and such? these can suck up huge amounts of energy and go from very small to very big in very much the same sort of thresholding effect you were seeing with the ventilation collapse on the main foil.

Obviously you've modeled the thing in CFD, but did you stick it in a wind tunnell to make sure that you weren't shedding/creating unexpected vortices?

[Tom Ray]

...The steering is very positive and thanks to the work put in by the design team, the boat itself seeks stability... unlike VSR1. I often reflect back on what an unstable beast that one was. I think about how it pretty much went at similar speeds to what VSR2 is doing now... but was always on the edge of flipping out. It really was like flying a plane backwards. I wouldn't have put anyone in that boat in top end conditions. Not because of skills... but because it simply wasn't that safe. In the end I did feel comfortable in it....

You're able to be comfortable when flying at 50 knots inverted?

[larso]

In reply to Raked Aft: there are a few methods that could be used for the transfer. You do have to remember that things are happening pretty quickly as these boats accelerate hard from 15-45 knots (Check out the old 'Sailrocket goes ballistic' video). Obviously you can slow it down by simply sheeting out. The thing is that during the acceleration phase I am also sailing in towards the shore. I sail this profile in order to initially generate the apparent wind speed and angle to get going... just like any fast sailing craft. Once I have hooked into the wind I keep sailing in to the shore with the wing slightly eased. I basically want to get into the flattest water so I can point-and-shoot a straight run down the course. This is usually done at around 40 knots plus and I want really positive control. It's where the Mk1 used to get spooky as sometimes she would simply spin out the other way towards the shore. As soon as I am into the bear away I sheet in the remaining wing angle to the desired 10 degrees and focus on holding the straight line... and just checking a few things out i.e. the thin mainsheet can stretch a little along the run and need some fine sheeting, check the leeward pod height which can be lowered by a flap control line, look to see how high the foil is riding, raise the low speed rudder all the way manually (drag normally kicks it up automatically most of the way by 25 knots). So I do want to have a very positive changeover if going from Water to air for steering... and I want to know that the control will remain if I need it in a situation. In some respects, I guess we have moved on the side of caution whilst we still excorcise the fears we had with the first boat. We lost control a lot with that boat. The new boat is designed to be super stable. It is super stable. We just need to fully trust it to be. I think I do now. We did try the air rudder on the Mk1 and we did make a few systems to make it work. We now know that it would never have worked on that boat. The weight was simply in the wrong place. When we first took SailRocket 1 down to Weymouth to the sailing academy, a week or so later another container appeared next to ours with this incredible looking craft sitting between the two. It was Richard Jenkins kite powered WindJet. I walked around it for an hour just looking at how his fertile mind had solved the same problems we had been working at. He had a system for going from hydro to air rudders similar to that which you described... very similar in fact. It was a neat solution. So yes, something like that would work. Not so whacky after all.

To answer Baltic Bandit... A lot of work was one on the aero package using CFD. It was constantly refined through all its design iterations. The wing was worked on the hardest and once again, a lot of work was done by Chris and wang at Aerotrope to reduce tip losses. We figured we had big tip losses from the Mk1. On VSR1 we had used a flap on the outboard end of the beam to generate lift to fly the static weight of the wing and beam. The trouble was that the lift and hence pressure areas generated were in conflict with those of the lower wing in the same proximity. The low pressure on top of the beam would meet the high pressure on the windward side of the lower wing tip. Even with an elliptical wing designed to reduce tip losses... we would get a big aero mess down there. Sailing near sunset we would often be blasting down the course with the magnificent African sun setting behind us... brilliantly illuminating the massive swirling tip vortice coming off the lower tip-beam junction. We played around with a few tricks including fences and such but it made little noticeable difference. On VSR2 we really focused on this area. The static weight is now carried by the outboard, horizontal wing extension. This is a huge improvement as the lift is complimentary to that of the wing. It has greater leverage and makes the wing feel like it has a higher aspect ratio (whilst keeping the center of effort low). The extension also reduces tip losses by operating close to the water surface. this Ground effect greatly reduces tip losses. The new wing is not only bigger, but also markedly more efficient than the Mk1 wing. The new beam is now purely aerodynamic and is not loaded. It actually twists towards the outboard end to match the local flow of wind around the lower wing. The fuselage is also unlikely to generate large vortices. Even the floats were designed with consideration for their AWA cross sectional profile. All that said, the pre-set angles of the fuselage, floats and appendages is set for around 26 degrees AWA. If we do not achieve this angle then we may have aero sections carrying a decent side load and hence generating induced drag. I have raised this point with Chris but he simply sees it as being a very small part of the whole equation. We are looking for a missing 100kg of thrust ... or more likely, an additional 100kg of drag at 50 knots in 26 knots of wind. Even if the aero was double what it is supposed to be... we would not be close. On the other hand, it could simply be a cumulative effect of many things that need to be cancelled out. It still seems odd that it is the same speed regardless of wind strength, foil or boat. We remain open minded.

In reply to Tom... The first thing that struck me about lifting off in VSR1 was how dry and quiet it was. She swung through pretty quick as I had no vertical restraint on i.e. the seat belt would stop me going forward but not up. It was on like a coat hook so I could get out easily but not get thrown forward. The only way I stayed in that seat was by the G-forces... even inverted. I must have been comfortable... because those muscles that relaxed don't normally do so otherwise!

[Tom Ray]

... All that said, the pre-set angles of the fuselage, floats and appendages is set for around 26 degrees AWA. If we do not achieve this angle then we may have aero sections carrying a decent side load and hence generating induced drag. I have raised this point with Chris but he simply sees it as being a very small part of the whole equation. We are looking for a missing 100kg of thrust ... or more likely, an additional 100kg of drag at 50 knots in 26 knots of wind. Even if the aero was double what it is supposed to be... we would not be close. On the other hand, it could simply be a cumulative effect of many things that need to be cancelled out. It still seems odd that it is the same speed regardless of wind strength, foil or boat. We remain open minded.

In reply to Tom... The first thing that struck me about lifting off in VSR1 was how dry and quiet it was. She swung through pretty quick as I had no vertical restraint on i.e. the seat belt would stop me going forward but not up. It was on like a coat hook so I could get out easily but not get thrown forward. The only way I stayed in that seat was by the G-forces... even inverted. I must have been comfortable... because those muscles that relaxed don't normally do so otherwise!

So parts of the boat are not aligned for minimum drag until you reach top speed, and are constantly crabbing through the air? I'm surprised that's not considered a big problem.

Did you know the first boat would go over backwards if it let go of the water, as it ultimately did? What would this boat do if its foils got free of the water?

I'm glad you were not hurt and are crazy enough to keep trying!

[larso]

... All that said, the pre-set angles of the fuselage, floats and appendages is set for around 26 degrees AWA. If we do not achieve this angle then we may have aero sections carrying a decent side load and hence generating induced drag. I have raised this point with Chris but he simply sees it as being a very small part of the whole equation. We are looking for a missing 100kg of thrust ... or more likely, an additional 100kg of drag at 50 knots in 26 knots of wind. Even if the aero was double what it is supposed to be... we would not be close. On the other hand, it could simply be a cumulative effect of many things that need to be cancelled out. It still seems odd that it is the same speed regardless of wind strength, foil or boat. We remain open minded.

In reply to Tom... The first thing that struck me about lifting off in VSR1 was how dry and quiet it was. She swung through pretty quick as I had no vertical restraint on i.e. the seat belt would stop me going forward but not up. It was on like a coat hook so I could get out easily but not get thrown forward. The only way I stayed in that seat was by the G-forces... even inverted. I must have been comfortable... because those muscles that relaxed don't normally do so otherwise!

So parts of the boat are not aligned for minimum drag until you reach top speed, and are constantly crabbing through the air? I'm surprised that's not considered a big problem.

Did you know the first boat would go over backwards if it let go of the water, as it ultimately did? What would this boat do if its foils got free of the water?

I'm glad you were not hurt and are crazy enough to keep trying!

Damn... you just can't make some people happy! This is perhaps one of the most aero yachts ever devised... perhaps second only to MI or Ypages. We are only worried about top end speed and have determined that some mis-alignment as we accelerate isn't a big issue. It is actually quite disappointing how little the aero efficiency contributes in relation to the hydro drag. All I can say for now is if you are looking at the stuff out of the water as the problem... you are looking too high. The hydro is the issue. The aero stuff may contribute of course... but it is not the trick. Even the design team who went to great efforts to reduce the aerodynamic drag are quick to dismiss it as being relevant to our current 'glass ceiling' issues.
Yes we did know that the first boat was going to have issues. Malcolm actually got it spot on when he first designed the boat. You have to remember that the record had been dormant for a long time when we set out to break this record in 2001. Yellow Pages had already ruled the roost for 8 years and the record was 46.52 knots. When I asked Malcolm about the limit of the VSR1 design he said that it would encounter what he termed "a pitch instability" in the low to mid 50's. I asked him what it meant and he laughed that it meant it would take off. As we developed VSR1, the record got higher and higher. Pretty soon we were pushing it to its design limits and aiming over 50 knots. I sort of forgot about low to mid 50's as we faced problem/crash after problem/crash. In the end we made huge gains with a new steering/control system. We finally had the ability to maintain control and thus realise the boats/concepts potential. We booked our first WSSRC record attempt and in short time we knocked off both Yellow Pages and Hydroptere (who in 2008 had just beaten YP and become the fastest boat after YP's 15 year reign). I didn't realise that we had also hit over 51 knots on that run. The little GT31 GPS we use didn't accurately record it... but the big Official Trimble GPS did. When I look back at that run now, I can see how close we were to going over the edge. She had a sniff up there a few times. On the next run I thought the boat was unflappable and just went all out. The wind had picked up a couple of knots and I was sure I was about 16 seconds away from reaching our goals. VSR1 was in great shape and accelerated like the weapon she was. I had barely turned onto the course and hadn't even pulled the wing flap on when she took off at over 50 knots helped by a combination of overall flex and steering effects attributable to inclined foils. I can't honestly remember when it occurred to me that "hey, we must be doing over 50 knots". I sort of remember the thought occurring when I was upside down... but your memory plays tricks in those situations. I do remember recollecting Malcolms high speed concerns from long ago though.
So we were the fastest boat in the world three years after launching VSR1 with the wing. Kind of annoyingly, 14 days later... after 15 years of not being able to beat their own record, the Yellow Pages team took the boat record back and were the first 'boat' (not board) through 50 knots. Hydroptere had that big wipe-out. There was a lot going on then. We were all pushing hard... often on the same day in different parts of the world.

[auscat]

http://youtu.be/p5T08pV-MBU

The wind is back.The anticipation is killing me can't imagine what it must be like for these guys.

[mitchellsailor]

WOW! thinking about what you guys must be feeling after hopefully finding the "hole" is droolworthy. "lets just imagine every foil is ventilating" haha, good luck to you and your work is amazing

[Mojounwin]

Yep, I check for updates several times per day. This lack of wind is a pain in the ass. It's like someone turning off a good movie 10 minutes from the end.

Let's hope the new fence does the job and the wind kicks in.


Cheers
Mojo

[larso]

We went out yesterday and knocked out another great low wind performance. The boat seems to have changed radically with the new fences. We did a 43.8 knot run and 46.22 peak in winds of only 18-21 knots. This represents a huge increase in light wind performance. The new foil package is tiny in comparison to what we have used before and yet it is outperforming the bigger foils. The large back skeg is what gets us started though. The fact that the back of the boat is now riding high and the foil is riding way higher is what really boosts the performance. There is still a lot of spray but I think that comes with the 'surface piercing' territory. When we designed this boat I always said there would be a 60' rooster tail coming out the back. You can afford that if you have the grunt. Ever seen a drag boat?
So I'm pretty excited about how this thing is going to go in strong winds. The next big day is Sunday. As is the way in this game... it's all or nothing. It looks like it will be straight back into top-end stuff. This glass ceiling could be in for a rough day.
On another note, we dodged a bullet yesterday with a 'happy breakage'. Happy because it happened in light conditions and didn't cause any secondary damage. A small retaining collar on the mast that stops it from riding off it's swivel base let go. The spar started to come apart whilst still in the air as the supporting strut pushes it up when under compression. Luckily we caught it and managed to carefully lower it all. If that had of happened on a top-end day it could have quickly escalated into a real mess. VSR2 is now all pulled apart for more detail checking.
I have a good feeling about what is about to happen. This boat has some real big ambitions.
Cheers, Paul.

[DaveK]

Thanks for the update and good luck to you guys!!!

[Tom Ray]

We went out yesterday and knocked out another great low wind performance. The boat seems to have changed radically with the new fences.

So you have been cruising around at 50 knots with cavitating foils this whole time? I'm amazed they would work well enough to do that when cavitating.

Glad your failure happened at a not-so-bad time.

If you have a problem with lack of wind, schedule a fishing trip on a powerboat. It can cause a mighty gale.

[jackson19540316]

Incredible....................................wow !!

[fastyacht]

We went out yesterday and knocked out another great low wind performance. The boat seems to have changed radically with the new fences. We did a 43.8 knot run and 46.22 peak in winds of only 18-21 knots. This represents a huge increase in light wind performance.

You know, if we measured sailing records as relative to windspeed rather than absolute speed, I think you have it already. That is astounding--more than twice the windsspeed!

[fastyacht]

SailRocket is starting to get that hard slapping bounce that hydroplanes get. That's got to be good. Seems hydros go for WIG lift to get out of the the water more than foils, which seem to be used more for tracking?

Wondering about what looks like a fair bit of Aero wetted surface too. Maybe it just takes an oooch to get through that?

Go SailRocket!

Those are good observations. In fact if you look at minimum drag designs, indeed, hydrofoil support is only best in a fairy narrow range (discounting issues of sea state). Over 60 knots, WIG becomes considerably more attractive.

The very interesting thing about sailrocket is the inherent balance of the system. All the hydrofoil has to do is keep the thing from blowing away. Because the rig develops lift as well as drive, there is a reduction of displacement as it sails. At the speeds this is theoretically capable of, the apparent wind will get up to 80 knots or more (that's a freaking hurricane!) and what little displacement might be left is certainly better carried by that "hydro slapping" WIG action than by additional foils with their considerable parasitic drag.

[larso]

One of the real notable points that indicate the new efficiency of the foils is that the small wind indicator mounted in front of the cockpit was pointing straight ahead i.e. the apparent wind was aligned with the fuselage for the first time. It's not only the fuselage that aligns but all the other little draggy bits. Mind you, all the vertical float support brackets will actually be generating thrust before they align. Either way... she is starting to do her thing. Let's see how this relates to 60 knots though. Until I see it myself I remain healthily skeptical.
The strong forecast is crapping out by the way... Surely it has to go the other way soon.
Cheers, Paul.

[Tom Ray]

The strong forecast is crapping out by the way... Surely it has to go the other way soon.
Cheers, Paul.

Sometimes it is necessary to actually rig rods and prepare a fishing boat.

[Mojounwin]

Paul, when do you have to pack up and go home?

Cheers
Mojo

[larso]

Hey Mick, we are aiming for flying out of here on the 3rd of December... but have visas until the 15th. I really hope it doesn't come to that. Mondays forecast is back up again. I think we are on the edge of getting or not getting this wind. It depends how far up the coast it stretches. Yesterday they had 35 knot winds down south in Luderitz... we had SFA! Monday could go either way. Obviously we are committed here so we get what we get. We just have to be ready to deal with it when it comes.
It would be nice to send some big run news down South rather than sitting here and watching them bang out the big numbers. Did you see that the windsurfers broke there own records yesterday?
Cheers, Paul.

[shaggybaxter]

Good luck Paul,
We swapped some emails back I think in 1999 when you were prepping Team Phillips, and I was can remember being blown away at the technology of that boat. Now look what you've gone and done. You're making a 120ft cat look like a pussy.
You guys are simply oozing historic moment right now.
There will be the wind guys, this is your time.
SB

[Tucky]

Paul, thanks for your comments. It makes the whole effort of what you are trying to do come alive. I've had a copy of "The 40 knot sailboat" for years- a nice old hardcover copy that remembers the time when Bernard Smith imagined the concept. It is so cool how you all have made the concept real, and made the boat your own. Sometimes the imagineer gets more credit than the folks that actually make it real. I think you all deserve tremendous credit for actually building and sailing this monster of a boat, and I expect Smith understood this as well.

[larso]

 Grabbed Frame 13_1024x768.jpg   70.14K   56 downloads
I was fortunate enough to get in contact with Bernard Smith before he passed. I was given an old number of his by another fan... so I called it hoping there would be some family there. I was pretty stunned when he answered the phone (at 98 years of age). We had just reached 40 knots for the first time in the Mk1 and I figured I should let him or his family know that the ol' boy wasn't so crazy. It was an absolute pleasure to speak to him on occasion. We discussed that boat and the new one. He didn't do e-mail so it was all by phone or hand written letters. We made up 40 prints from that run and got him to sign them. Number 1/40 is still on his wall. He passed away just shy of his 100th birthday but I can't feel sorry for a guy who lived such an amazing life. He was a genuine rocket scientist. I know it made him very happy to know that someone had taken his ideas and was 'running' with them.
Reading his book changed how I viewed sailing boats and their potential forever. Even now I wonder about some of his more whacky ideas. We have taken his original concepts and added all the modern twists to take them from 40 to 50 and hopefully beyond 60 knots. These boats wouldn't exist if he hadn't sat down and written his thoughts in such an elegant way.
I hope this pic comes out. It's off the HD video so it's not ideal. The perfect flamingo shot is still out there.

[Tucky]

 Grabbed Frame 13_1024x768.jpg   70.14K   56 downloads
I was fortunate enough to get in contact with Bernard Smith before he passed. I was given an old number of his by another fan... so I called it hoping there would be some family there. I was pretty stunned when he answered the phone (at 98 years of age). We had just reached 40 knots for the first time in the Mk1 and I figured I should let him or his family know that the ol' boy wasn't so crazy. It was an absolute pleasure to speak to him on occasion. We discussed that boat and the new one. He didn't do e-mail so it was all by phone or hand written letters. We made up 40 prints from that run and got him to sign them. Number 1/40 is still on his wall. He passed away just shy of his 100th birthday but I can't feel sorry for a guy who lived such an amazing life. He was a genuine rocket scientist. I know it made him very happy to know that someone had taken his ideas and was 'running' with them.
Reading his book changed how I viewed sailing boats and their potential forever. Even now I wonder about some of his more whacky ideas. We have taken his original concepts and added all the modern twists to take them from 40 to 50 and hopefully beyond 60 knots. These boats wouldn't exist if he hadn't sat down and written his thoughts in such an elegant way.
I hope this pic comes out. It's off the HD video so it's not ideal. The perfect flamingo shot is still out there.

Thanks so much for that- much better than I'd have hoped. I'll have to go pull out the book and read it again. I'm fascinated by the physics of sailing and he resolved a lot of conflicting forces in a brilliant way. I hope you hit 60 safely.

[HANDYCAP10]

its an exciting time in sailing right now. i know that there have been countless other surges of devolopment in the past - but with projects such as the AC72s and VS2, my days at work are far easier to cope with. thank you Larso and crew for pushing the boundries - and keeping us all so well informed.

[P Flados]

For those in this forum, I have been following the Paul & the Sailrocket effort since before they went to Walvis. To me, it would appear that Paul's recent foil discussion (see below) holds more than a little bit of promise to be that key element that may explain what has always seemed unexplainable for the sailrocket "glass ceiling". If, it is, he now has the information that can be translated into a fix & a big leap in performance. We (Paul, his team, and all of his supporters) have kind of been here before thinking they we only a small step away from success, so we understand that the only proof will be a big change in the top speed. Again, I am hopeful and cheering the team on.

The fact the Paul shares these kind of details is just outstanding and one of reasons that following his efforts has been so rewarding.

From the 11/5/12 entry to Paul's blog:


The standby time has allowed us to think long and hard about our current performance predicament. We had our design meeting where Chris, Malcolm and myself had a long Skype discussion about likely scenarios. Basically we tried to reverse engineer the problem and our train of thought was as follows...


-The most likely candidate that would be giving us a sudden, large loss of performance regardless of power input is cavitation.

-The rudder is not loaded highly enough nor does it have the base area to give us such a sudden drop in performance... although we will continue to put sensors on it to make sure it isn't contributing.

-So... the most likely candidate for caviataion is the suction surface of the main-foil.

-The main foil shouldn't begin to cavitate around 52 knots unless it is 40% overloaded.

- How could the main foil be 40% overloaded at such a relatively low speed?

- If the upper portion of the foil, the part that enters the water, was ventilating (highly likely as it is at the surface), then what effect would that have on the boat?

- On checking the numbers, AEROTROPE deduced that if the transition (curved part of foil) was ventilating down its suction side... then we would lose about 30% of our lateral loading area. At 52 knots... this would lead to the lower section of the foil being overloaded by... wait for it... 43%!

-It would cavitate

- AND... the back of the boat would ride very low... as it has been doing...

- AND... pitching the foil up would most likely have little effect and may actually make it worse by leading to more upper surface ventilation (as we have often seen)

So, this all seems to fit together very nicely. This in itself kind of makes me suspicious. Nonetheless it is a great starting point. Some parts are kind of obvious i.e. that we are getting ventilation near the surface of a shallowly (?) inclined surface piercing foil but others aren't. The foil was already twisted so that it would be lightly loaded near the surface to prevent ventilation. The fact is that what happens at the surface is very hard to predict, especially in chop. We have added substantial 'fences' to the foil to try to prevent the curved part of the foil from ventilating. We have started big as it is easier to chop them down than build them up. We have fences on both sides.

[shaggybaxter]

How is the weather forecast looking? Is Sunday still on track?

[Amati]

 Grabbed Frame 13_1024x768.jpg   70.14K   56 downloads
I was fortunate enough to get in contact with Bernard Smith before he passed. I was given an old number of his by another fan... so I called it hoping there would be some family there. I was pretty stunned when he answered the phone (at 98 years of age). We had just reached 40 knots for the first time in the Mk1 and I figured I should let him or his family know that the ol' boy wasn't so crazy. It was an absolute pleasure to speak to him on occasion. We discussed that boat and the new one. He didn't do e-mail so it was all by phone or hand written letters. We made up 40 prints from that run and got him to sign them. Number 1/40 is still on his wall. He passed away just shy of his 100th birthday but I can't feel sorry for a guy who lived such an amazing life. He was a genuine rocket scientist. I know it made him very happy to know that someone had taken his ideas and was 'running' with them.
Reading his book changed how I viewed sailing boats and their potential forever. Even now I wonder about some of his more whacky ideas. We have taken his original concepts and added all the modern twists to take them from 40 to 50 and hopefully beyond 60 knots. These boats wouldn't exist if he hadn't sat down and written his thoughts in such an elegant way.
I hope this pic comes out. It's off the HD video so it's not ideal. The perfect flamingo shot is still out there.

You, sir, may stay. Some books you read over and over, and you become part of the cultural virus.

Way beyond sixty, dude.....

[Tom Ray]

For those in this forum, I have been following the Paul & the Sailrocket effort since before they went to Walvis. To me, it would appear that Paul's recent foil discussion (see below) holds more than a little bit of promise to be that key element that may explain what has always seemed unexplainable for the sailrocket "glass ceiling". If, it is, he now has the information that can be translated into a fix & a big leap in performance. We (Paul, his team, and all of his supporters) have kind of been here before thinking they we only a small step away from success, so we understand that the only proof will be a big change in the top speed. Again, I am hopeful and cheering the team on.

The fact the Paul shares these kind of details is just outstanding and one of reasons that following his efforts has been so rewarding.

From the 11/5/12 entry to Paul's blog:

... We have added substantial 'fences' to the foil to try to prevent the curved part of the foil from ventilating. We have started big as it is easier to chop them down than build them up. We have fences on both sides.

This makes sense. Outboards have a cavitation plate because propellers suck. I hope you see the expected jump in speed with the new fences.

[Luke Piewalker]

If you send me a plane ticket I can guarantee wind strength and direction, just light a barbecue, the wind will rise and the smoke shall inevitably be blown in my direction....

[mad]

53.1 knot average a few minutes ago.

[Tom Ray]

53.1 knot average a few minutes ago.

Does this mean they are not thinking hard enough about fishing, or there is still an unknown drag problem?

[mad]

53.1 knot average a few minutes ago.

Does this mean they are not thinking hard enough about fishing, or there is still an unknown drag problem?

From my understanding that's an improvement, seems to be when you read here

http://twitter.com/sailrocketlive

[auscat]

56 knt peak is pretty impressive,shows it really is possible.

[coreymon]

61.23 peak 54 average sweet!

[Fasterdamnit]

Booo Yaaaaaa!!

That Bell X-1 orange is looking sweeet! Can't wait to see how far they can push her now.

[auscat]

You little rippa Larso.Can't wait to hear the official numbers.
63 knts top speed posted on facebook from the official gps.

[tackoften]

Good on ya Larso,,keep it going mate,,,we are all watching and waiting,,,

[Doug Lord]

Way to go SailRocket! ( Hydroptere peak 61 knots, average 51.17 over a nautical mile) http://sailrocket.com/node/615

From Paul Larsen:
Mon, 12 Nov 12 19:14


Just in... 61 + knot peak speed and a 54. something average. Had to stop as the end was coming up fast. Everything went into fast forward. I was saying " this is fast, this is fast" and then she took off again... "this is real f*****g fast"!!!
I thought we might have bagged the outright as well... as you would after hitting over 60 knots... but the average wasn't there... I think. We haven't downloaded the big TRIMBLE yet. Everyone is getting the data down now. We broke our own PB twice today... so that's 2 x triple rum and cokes in pint glasses... and of course the 60 knot bottle of champagne also falls. Happy days.
What a great relief.
I know the current world record is toast... hell, they can even raise it a bit if they want.
Life for VESTAS Sailrocket 2 starts at 60 knots. Today she walked on stage. She was beautiful to drive. Totally in control.
I got Helena to come down to the end of the course before I checked the speeds. I wanted her to be there. Unfortunately she had her phone in her drysuit pocket so that was the end of the Tweets.
Righto... lots to do.
The outright record remains to be beaten.
I'll let you all know the actual numbers when I know myself.
Happy days alright.
Nice work team... real nice.
Cheers from one beaming Australian in Namibia.
P

[Icedtea]

Well fucking done boys, get out there and send it, she's just waiting to be let rip!

[coreymon]

You little rippa Larso.Can't wait to hear the official numbers.
63 knts top speed posted on facebook from the official gps.

link?

[BahamaBank]

Wow!

Really pleased for them. Been following them for the past few seasons.

If they get better conditions Vestas Sailrocket will average way faster than this.

Certainly justified its Bell X-1 looks today :-)

[Murphness]

Well done boys! Put the kites to bed!

[Mojounwin]

Nice one guys. Now you know it works, time to go break the record.

Cheers
Mojo

[Tunnel Rat]

Well done guys. Greatly deserved for your tenacity at sticking with this for so long. It must be a wonderful feeling - they are all probably bouncing off the ceiling right now.

The link to Paul's blog is http://www.sailrocket.com/blogs

[P Flados]

Payday is approaching for the SR team.

They had the right approach and the determination to build the tool they now have.

SR2 is a true single purpose outright speed machine that has what it takes to make the next leap in performance.

Walvis bay will do fine for the 500 meters. They can just make 1 nautical mile runs, but I do not think they can really expect to be a top performance for the full mile at this location.

As long as the wind co-operates and the equipment does not break, they will walk away with the a convincing increase in the World record.

Go SR2 Go!!!!!!!!!!!!!!!!

[fastyacht]

I still remember how impressive it was to see CROSSBOW do 26 knots. Wow, look now! Makes CROSSBOW look like an Optimist racing a 49er!

[larso]

Righto, here it is, hot off the big TRIMBLE gps (used for official ratification)...
Peak speed... 61.92 knots
500 m avg... 54.08 knots
1 second avg... 61.58 knots
5 second average... 59.08 knots
The course was rough at the top so I cruised into the flatter water with the wing well eased. Once I was happy that the runway was smooth ahead I sheeted her in and away she went. I knew it was quick and said so over the comms. I could see a gust ahead and held on until we hit it. VSR2 just went into fast forward mode and accelerated hard again. I knew it was quick... real quick. I also knew it was low tide and the shallows at the end of the course were now approaching at a new and exciting rate. I held the gust for a few long seconds then sense prevailed. The boat was accelerating hard right up to when I bailed out of the run. Stopping from over 60 knots was going to be a whole new experience. Obviously we were chewing up runway fast. She actually stopped in a pretty civilised manner and I managed to avid grounding. I was buzzing. I knew it was 60 plus.
So the average was down but the 5 second average perhaps gives a better indication. I reckon she will hit over 65 knots in her current configuration if we get the right conditions. Yesterday was fine. One more like that please Walvis. It was a brilliant day for all the team. A huge relief to see the numbers become reality. The boat is a weapon. Life begins at 60 for this one. Yes I have a hangover... and yes it feels bloody great!

[Tom Ray]

Thanks for the updates, Paul! Congratulations! Can't wait to see you post a 60+ average speed.

Can you expand a bit on what it's like when this weird critter slows down in a "pretty civilised" manner?

Ever consider some kind of an air brake like gliders use or a parachute like dragsters use so that you can use less "runway" slowing the boat down?

[shaggybaxter]

Heheheh...
How can you follow this and make the words worthy?
Couldn't have happened to a more deserving bunch, this is what perseverance and passion can do.
Congrats from all at home guys,
SB

[shaggybaxter]

Oh, and to the engineers and others that worked through the foil drag, that is as good as it gets.
Take a bow gentlemen, you deserve it.
SB

[blunted]

Nice one Larso, keep at it.

B

[Tucky]

Oh, and to the engineers and others that worked through the foil drag, that is as good as it gets.
Take a bow gentlemen, you deserve it.
SB

+1. Way to go everybody.

[Guitar]

Fucking amazing. Go Team Vesta SR!

Awesome job everyone!

Rick

[MR.CLEAN]

righteous!

[fastyacht]

over 60 knots. That's iceboat territory! Heck I don't think a DN can do that. Eskeeter yes....and on WATER!

[Mambo Kings]

Its a great feeling when the good guys start getting the results they deserve.

[larso]

Here's the video from yesterday... Boom
Great to see the windsurfers get into the 50 knot club. Happy days in Namibia.

[tackoften]

Luv ya work,,cant wait till Friday,,proud Aussie,,,,

[Fasterdamnit]

Here's the video from yesterday... Boom
Great to see the windsurfers get into the 50 knot club. Happy days in Namibia.

You and your team truly have the Right Stuff! Just incredible!!


Bravo!

[pcraig]

Congratulations Paul.

Aiming for the 60kt average now?

[Big Show]

Nice! Rocket indeed.

To infinity... And beyond!

[PIL007]

Absolutely F#cking awesome.....your programme will succeed and we are proud. 60kts...who would have thought.

[Doug Lord]

Congratulations, Paul! More here: http://www.boatdesig...h-36825-10.html

[DryArmour]

I don't know if bigger is faster in the case of foiling boats. Would an AC 72 budget be able to create a larger, faster boat or high aspect and taller wing? would that help or no? I know it is a delicate balance between weight, wetted surface and loads/strength of vessel.

[OzScoutSailor]

Nicely done guys!

[faijai]

Brilliant work Vesta team.
Been following you for years and it has been great watching the evoloution into this speed machine.
Belief is all and it is only a matter of time now!
Well done.

[Torsten]

That is just fucking bananas! Love ya work Larso, congrats!