A bonus day yesterday but nothing today.
Thu, 24 Nov 11 14:32
We managed to get out on the water for the last two days but today looks like it won't get going.
On Tuesday we went out to try some stuff but it was too light to get started. I was still contemplating driving down to Luderitz to see the kiters go for it and deliver the WSSRC observer but it all got too last minute. After many calls back and forth with Seb Cattelan based on organising the long trip and our ever changing forecast, we decided to stay and hope for a sail. We had all but called off yesterday at 4pm when the wind began to build over 20 knots. I took a good reading with TACKTICK instruments and got a steady gust of 21 knots. Everyone was relaxing in the container doing e-mails and stuff. In one hour and five minutes we were at the top of the course with the wing up preparing for a run. It was a pretty good scramble all in all.
We have decided to have another look at the conventional foil and see how far we can push it. We mounted it on VESTAS Sailrocket 2 but didn't have any fences on (Fences are like little skirts around the foil which stops air from getting sucked down from the surface). The wind was lighter today and this foil should be a whole lot more efficient. It should be capable of runs well over 50 knots in steady winds around 24-5 knots. It was obvious quite quickly that we had made the right choice to head out. Helena was getting gusts up to 29 knots but there were big holes in the wind where it would drop down to 17. It was an odd day.
The first run went pretty well and VESTAS Sailrocket 2 accelerated hard. The pod flew early and I was able to control it with the flap control line on the right of the cockpit. Just past the timing hut she did a big yaw away to leeward and I had to apply a fair bit of rudder to bring her up on course. I thought something had let go but everything still seemed in place. I slowed down and bailed out of the run anyway. We still managed a peak speed over 49.5 knots but the average was down due to the holes in the wind. I was pretty sure that we had suffered ventilation and that is what caused the yaw down the course. Fences are pretty critical at high speed, especially with surface piercing foils that don't have a boat on top of them to separate them from the air.
THIS SHOT SHOWS THE SPRAY FLYING OFF THE TOP SURFACE OF THE FOIL AS IT GOES INTO THE WATER, ALSO VSR2 IS RIDING LOW AT THE BACK. THIS SUGGESTS THAT THE UPPER SECTION OF THE FOIL ISN'T WORKING VERY WELL NEAR THE SURFACE. THIS IS EXPECTED. WE WILL SEE HOW THE FENCES CHANGE THINGS.
I did another run but experienced the same sort of drag.
We called it a day and headed back in happy that we had been out at all. It was a very productive day.
Now that we are in the midst of a record attempt we have to give ourselves every chance of success by any means. We still believe that the future will be in the usage of the new ventilating foils however we can also use this fantastic craft to find the limits of conventional foils. Many people have suggested that if we have the power to drag the new wedges down the course at over 54 knots then we should effortlessly be able to pull a much sleaker conventional foil at the same speed and even higher. Even if it does start cavitating we may have the power to drag it up to the current record. This is why we have one of each type of foil here. If the forecasts are lighter then we will use this foil. We have VESTAS Sailrocket 2 setup so we can quickly switch between the two setups. Yep... the ol' switcharoo!
So, figuring that we had pushed this conventional foil as hard as we could without fences, we now have to try it with them on. They can make a massive difference. Apparently the mighty Hydroptere would barely even work without them on her big surface piercing foils.
We have fitted two fences today and we are ready and waiting for the wind to fill in. It's a beautiful day today... but no wind.
Every day VSR2 just gets better and better. It was so easy sailing in the lighter wind conditions. Effortless.
The kitesurfers had very strong conditions down in Luderitz the other day and Seb managed a 53+ knot run... but no new outright record. Rob Douglas remains the man to beat at 55.65 knots.
We are ticking the boxes and constantly illuminating the path forward. We will get there.
Cheers, Paul.
Foiled again
Submitted by P.Flados on Fri, 12/02/2011 - 03:23.Pardon the length below, but I be will building up to a point.
As is frequently done, I will refer to he apparent inability to exceed a specific speed even as wind speed increases as "hitting the wall" or just the "wall".
Hitting the wall has been observed by many displacement craft that are limited by a specific "hull speed". This is not applicable VSR, VSR 2 or other foiling / planing craft. Foiling craft have a different but very hard to penetrate wall. This was noted long ago by the Trifoiler / Longshot team.
The Trifoiler platform relied on foils for lift, automatic roll control and lateral forces (as needed for the sail/wing to provide forward thrust). Both VSR efforts use a foil to provide lateral forces primarily with a small vertical component (for vector balancing in pursuit of inherent roll stability). I was not surprised when the first VSR effort found their wall at a higher speed (10% - 15% or so) given the reduced reliance on foils.
VSR 2 did a good job of fixing most of the things that made VSR 1 risky to operate (Yea !!!!!!). VSR 2 adopted an easy change foil with two foils. One is a supercavitating version to try to penetrate the wall noted during runs of the original VSR. VSR 2 has hit the wall at about the same speed as the original with multiple foil configurations (Oh! - wailing and gnashing of teeth).
On the surface, the new results would seem to say that either the VSR 2 supercavitating foil just happens to have some new flaw that keeps the same wall (max speed) in place, or that there is more to the story than we think.
Gosh it would be great if some interested party following VSR 2 could have an epiphany, figure out the real reason and help the VSR 2 team beat this incredibly frustrating problem. They certainly have the tool (VSR 2) that would allow a simple foil change to confirm victory. They certainly have paid their dues (use of true innovation, diligent pushing forward, Paul putting his arse on the line riding the monster and just plain pain and agony) and deserve a break about now.
Ok, so now lets get real. No one is likely to just "figure out the problem". What we can do is really put on our thinking caps on and share any potentially useful results so that the VSR team can try some stuff that may ferret out this sneaky gremlin.
Here is my go at something.
Hitting the same wall with a traditional foil section and a wedge foil section was very unexpected. Highly unexpected results frequently tell us we are just plain doing something wrong. This begs the question:
"What single error or wrong assumption could cause both foil designs to produce the same speed limit"
That leads us to think about any SIMILARITIES in how the foils were designed. Were the required surface areas calculated using the same inputs and assumptions. Was the plan-form (shape) selected using the same process. Was the aspect ratio determine using the same criteria.
Even though I can make an argument that it would be great to have a foil with more surface area to try, I really just want to spur everyone to stop and see if they have any unique knowledge, experience or innovative ideas that could help all speed sailors (and wannabe speed sailors) make some real progress in blasting that darn wall into a pile of rubble.
Note that the above will also be posted on Boat Design Net just for more exposure.
keep pushing
Submitted by Hydromar on Mon, 11/28/2011 - 17:32.Great to hear your blow by blow accounts and great photos and videos. Were all rooting for you here on the Isle of Wight - hope to hear news that you have not only broken the record but smashed it!
Good luck Paddy & the team at Hydromar
Howdy Neighbour!
Submitted by mikevale on Sun, 11/27/2011 - 20:25.Good luck on your attempt Paul.
We are surveying just off Walvis Bay. I can tell you we've got 20+ knots due west out here but a bit too choppy for that orange boat.
All the best from the crew.
Foil shapes and theories...
Submitted by ormondotvos on Thu, 11/24/2011 - 20:24.Must be very exciting to be so close. As a former Tornado flier in the shallow windy waters of the Florida Keys, that hissing and thrumming of 30+ knots still rings in my dreams.
Could you enlighten us on which asymmetrical NACA shapes you're using, and maybe some tech diagrams with vectors? Some more advanced theory on the ventilation?
Are you using any theory from unlimited hydroplanes with their stepped lift plates and surface piercing propellers?
Good luck and happy Thanksgiving!
From Richmond, California
Awesome PIctures!!
Submitted by Wandering_Bear on Thu, 11/24/2011 - 18:19.Hey I really like the slower panning shots , they really give a sense of speed. Nice work!
Also the shots where the boat is heading towards the camera just shows the perfect balance with the pod out the water, & all straight & level - like proper Aviation speak!
Wel it is more of a plane than a boat I think.
Wishing you al the best from Peru.
Cant wait to open a bottle over hear to celebrate your success mate!
The Bear!