Sailrocket

Tue, 6 Nov 12 10:17

We managed to get out on the course yesterday in slightly marginal conditions. The wind was between 17-24 knots... mostly around 20. We were happy to have Dave and Gordon Cameron out as guests today. No one gets a free ride though and they were both happily put to work taking photos and assisting with the launch.

NOT A 'FRICKIN' LASER I'M AFRAID... JUST THE TOW LINE!

HOISTING THE RIG...

PREPARING TO RELEASE FROM THE RIB. YOU CAN SEE HOW VSR2 IS NOW HANGING FROM THE RIB AT A POINT AT THE REAR STUB BEAM. THE WING IS OVERSHEETED AND STALLED SO THAT THE NOSE OF VSR2 SWINGS AWAY FROM THE WIND. I USUALLY WAIT UNTIL I AM AT ABOUT 90 DEGREES TWA BEFORE RELEASING.

I was keen to see how the new double-sized rear skeg would assist us during start up. The answer is that in light winds that we normally wouldn't even get going in... it transformed the boat. I could now ease the wing out to get the flow attached and hold a straight course without having to drag the small front rudder along at full lock. I was in control at 5 knots... you know... like a normal boat. This will make a huge difference to how we do the following start up procedures. VSR2 lifted nicely up onto the plane as I accelerated towards the beach. I made an effort to raise the skeg as it had done its job and we were going fast enough for the main foil to be pulling effectively. It then got a bit funky. The new rear skeg is too big to fully retract even when raised to its limit in the rear float. This means it can still steer the boat if the rear float isn't flying.

As I bore away onto the course and accelerated further, the rear float raised clear of the water. It was obvious that the boat was steering was still being affected by the rear skeg because when it lifted clear, the boat jerked to windward. I responded with a heap of rudder, the back sank, the skeg kicked in, I steered, we accelerated, the back lifted etc... We only went through a couple of rapid cycles before we accelerated enough to settle into a flying mode. It was a little un-nerving. No issues at 25-30 knots but it would be a big issue at high speed. The good news is that for the rest of the run the rear float was flying high enough for this to have no effect.

I THINK THEY'RE FREAKY... THEY THINK I'M FREAKY... PROBABLY BEST WE JUST AVOID EACH OTHER.

The fact we were even sailing in this wind was good news. VSR2 felt slippery. Towards the end of the course she got her skates on and took off. She felt real slippery. We were not going fast enough to fly the leeward float but when I looked back at the rear foil It seemed to be riding at the fences. There was still a lot of spray.

THE FOIL IS RIDING NICE AND HIGH HERE. I LIKE THE PULSES IN THE SPRAY. THEY ARE MOST LIKELY CAUSED BY THE SMALL CHOP. THE COLOUR OF VSR2 IS INSPIRED BY THE BELL X1 THAT FIRST BROKE THE SOUND BARRIER. I BELIEVE SHE WOULD ALSO HAVE A SORT OF SONIC PULSE IN HER ROCKET EXHAUST. HUMOUR ME.

So it wasn't a fast run... we only averaged 41.3 knots but peaked at 47.3 knots. When I looked at the data from the shore weather station throughout the run there was one gust to 21 knots but generally the wind was around 19 knots. This marks a huge improvement for this boat in these wind ranges.

WE'RE ALL SURPRISED THAT THIS HUT IS STILL HERE. EVERY YEAR IT GETS A BIT LOWER.

On reviewing all the onboard footage afterwards I could clearly see the new fences working brilliantly. In fact they perfectly determined the ride height of the boat. If they stopped working then we would simply lose a bit of ride height until they became effective again. This means that we now have a lot less foil in the water and that the foil that is submerged is working well. This could explain the high boat to wind-speed ratio we saw towards the end.

UNLOADING THE TIMING AND FILMING CREW BEFORE HEADING UP THE COURSE.

LONG TIME SPEED-SPOT RESIDENTS.

It was a great little shake-down run and I was itching to see all the COSWORTH data at the end. The SMD pressure sensors we used on the rudder to test base cavity pressures showed that everything was A-OK up there. Oddly for such a low speed run, the rudder side loads were quite high. This could be a good sign as it could be a reflection that we are sailing at low apparent wind angles (with higher lateral loads)... and hence higher efficiency.

I decided to only do one run as it was obvious that we needed to slightly reduce the dimensions of the low-speed skeg. If we were going to sail the following day then we would need some time to do the 'chop' properly (it's done now. We are once again ready for sailing. Trouble is that the forecast has dipped again. Ho hum.)

Yesterday was a good day. Our theories seemed to be proven correct. We made some basic setting up mistakes with regards to recording data that was a bit annoying i.e. the masthead GoPro wasn't turned on, the onboard wind-speed oddly recorded everything but the run itself(????) and I didn't mount the little wind indicator in front of the cockpit which gives a nice simple, clear indication of how efficiently we are sailing. The fact is we need to be out sailing more often so all these procedures become routine. Last year we were sailing all the time and the team got very slick. The weather has not been so kind to us this time.

So we will try and sail again today but to be honest, I don't expect there to be much wind. I will still try and get out for the sake of the teams practice. We need more wind now to see if we really have found a way through the 'glass ceiling'. The only ray of hope on the forecast is next Sunday. It looks pretty strong so we need to make sure that we are ready for it when it comes. It looks like those days are going to be precious.

The whole team are quietly excited about how the new foils are progressing. The real proof will be when we start punching out the big numbers. We haven't done it yet. Until then we have to keep a lid on it. I do like what I'm seeing though. Yep, one of these days...

Cheers, Paul.

2 comments

Time to think and tinker...

Mon, 5 Nov 12 12:53

The Walvis Bay wind machine remains on safari... although we might get a chance to get out over the next couple of days. It has now been 16 days since we last had enough wind to get going. It's going from 'unusual' to ridiculous. The walls of the container begin to close in on us.

The WSSRC are now on-site so any runs we do from here will be officially ratified ones. Our record attempt period has started. The big TRIMBLE 5700 GPS is mounted on the boat. The gig is on!

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.

Looking at VESTAS Sailrocket 2 sail past, it is easy to see the energy lost in the spray that is thrown into the air by the high pressure side of the foil... but nearly impossible to see the energy that is lost by air being sucked into the water on the opposite suction side of the foil. Both need to be considered.

It is only our 6th run with this foil. In this respect I think we are developing it in the right manner.

I think our logic is sound and obviously I look forward to seeing what happens next. We may not get the fences right first time. We have other options for modifying the foil if this doesn't work. We'll see. One at a time.

We have begun to make a few changes to the foil as we always expected we would. Subtle changes at the speeds we are already travelling can make a big difference. I'll hang onto a some of the pictures, data and details for now. If there is one thing that the past year has taught me... there is very little real-world info about the hydrodynamic arena we are about to enter into. There are lots of theories but getting the hard data from the real world to verify them is the hard bit. Some of those theories strongly oppose the path we are taking. The data we have received already validates some of our decisions. It has been expensive to come by.

Ben has also made a new asymetric rear skeg to help VSR2 get started.

So far we have just been using the old original rudder off Sailrocket 1. It has worked OK but quite often its effect was marginal. The new foil is nearly twice the size. The purpose of this foil was to help our small high speed foils give traction at low speed. VSR2 starts in a highly stalled state and makes a lot of leeway. As it is skidding sideways, the weight of me in the front makes the front float sit low and this drags the nose of the boat into the wind. She won't bear away and I just sit there. If we add more lateral resistance at the back of the boat i.e. the new big skeg... then there will be more drag at the back and if I fully over-sheet and stall the wing, VSR2 will bear away to an angle where I can sheet out the wing and start sailing. Hopefully I can get up enough speed for the small front rudder to get a grip before VSR2 turns head to wind again. You have to remember that the boat is set up to be perfectly balanced at 60 knots. This particular boat and concept is more sensitive to its static set up than most other boats as the sail/wing has a large offset from the opposing foil.

The skeg will kick up as VSR2 accelerates. If not then I will pull it up manually as soon as VSR2 begins to accelerate.

For now, we sit on standby. VSR2 sits outside fully tooled up and ready for action. The wind is blowing nicely already but we have lost confidence in its ability to build as it normally would. The team is now milling about as we wait to see if it will build enough to go sailing. I want to get out today... even if it is just to see how well the new skeg works at low speed. Tomorrow is forecast to be stronger... but then the wind drops off again until the weekend. A big day is predicted next Sunday but I don't put too much faith in forecasts that far away.

Come on Walvis... reward our patience. We're waiting.

Cheers, Paul

10 comments

Bouncing off the ceiling!

Wed, 31 Oct 12 16:18

The Walvis Bay wind machine seems to have broken down. The powers that be that make this one of the best and most consistent speed sailing venues in the world have taken a break and left no message as to when they are coming back. It has been 11 days since we have had enough wind just to get started in and the forecast doesn't indicate anything strong enough on the horizon. It's very unusual for this time of the year. In my four years on location here I haven't seen it this 'flat' before. It's weird. It's slightly depressing to be honest.

As mentioned in the previous blog, we have had to commit to booking a WSSRC ratified world record attempt without even knowing if we have the performance to achieve our goals. VSR2 is still very much being dialled in. We have only done 5 runs since we arrived, 2 of which we didn't even get going over 10 knots. The last run was pretty good in 'boat' terms... but pretty average in 'Outright' record terms.

As a team, both here and in the UK, we are all scratching our heads as to why we are hitting this 'glass ceiling' at around 52 knots. Consider the simple facts we have seen to date...

- 2 different boats with 7 wildly different foils have all hit this speed

- The boats have been sailed in winds from 22-34 knots and only twice just exceeded this speed. Remember that in theory a 30 knot wind has nearly 50% more power than a 25 knot wind.

- Both boats accelerate very hard up to this speed and then flat line.

- VSR2 is designed to sail at over 60 knots and is sheeted accordingly. If anything she is a little oversheeted at 50 knots. The tell tales are all flying and she accelerates from 40 knots up to 50 with the same sheeting angle. We have eased the wing out a few degrees to allow for the fact that we aren't achieving the polars.

- The foils are specifically designed not to cavitate until at least over 60 knots. They are base ventilated wedges and we have gone to greast lengths to prove that the base is ventilated well down to tolerable/expected pressures throughout the run.

So, if it was simply a question of power... then we would go significantly faster in higher wind strengths. This hasn't proven to be the case. If the drag increase was gradual or even linear... then we would go faster in stronger wind strengths... we don't. The aerodynamic drag is only a small part of the overall drag picture. The front planing surface is the only thing in the water apart from the rudder and main foil at high speed. A simple V'd planing surface should have an almost flat drag curve as speed increases. The new rudder is smaller and more efficient than the last one in all dimensions. We are about to measure its base cavity pressures to make sure it isn't choking/cavitating... but am sure it isn't at speed (when the wind returns we will find out).

Thanks to all the sensors and the COSWORTH data logger package we have a lot of very useful information from each run.

LOOK AT THAT ACCELERATION ON THE YELLOW LINE. YOU CAN SEE HOW THE ACCELERATION LEVELS OFF EARLY AS THE WING IS ONLY PARTIALLY SHEETED UNTIL I BEAR AWAY ON TO THE COURSE AND SHEET FULLY IN TO 10 DEGREES. THE ACCELERATION THEN SHOOTS UP AGAIN UNTIL WE HIT THAT GLASS CEILING AT AROUND 52 KNOTS. IT STAYS THERE DESPITE SAILING THROUGH GUSTS UNTIL I SHEET OUT AND BEAR AWAY TO SLOW DOWN.

We are able to see how each aspect relates to the other. This graph above shows Boatspeed (yellow), rudder angle (red), rudder load (spiky purple... note it follows subtle steering inputs closely), Course over ground (lower grey), wing angle (playing up but still useful bottom dark blue), wind strength/angle (missing on this run), there are a couple of other load sensors in there.

We sit and stare at these graphs for ages, then we ponder them, lie awake in bed thinking about them... and come and check them out again. We question the accuracy of all the data and wonder how we can improve it. At moments like this when we don't have all the answers, we wonder if they aren't staring us right in the face. These light wind days give us time to ponder such things in depth.

So it comes down to this... if the nature of the drag was progressive or power dependent, sailing in significantly more wind would reward us with significantly higher speeds. We have simply hit 50-52 knots too many times now. This would suggest that the rapid rise in drag has been brought about by the foils in the water. Nothing else in the air or water could give such a rapid increase in drag. We know we are fully in the region where cavitation is likely. I can understand where the sub cavitation foils are failing as we are potentially near their limits, I can even understand where the first try at a ventilated/cav foil was failing (too big, too cambered)... but this new one is a hugely different foil in all aspects. It is specifically designed not to do the bad things that the first foil did. The new foil is the safe, reliable option and yet it simply hits the same glass ceiling as the last foil. That seems odd to me.

So we are all going over the boat, the data and having a fresh look at the basic principles. What are we missing? There is almost 100kg of thrust or drag not accounted for at our current speeds. It's a lot. Malcolm and Chris are meeting up at AEROTROPE in Brighton tomorrow to discuss the problem in depth. I'll skype in. If the wind was here we would be working progressively through the problem but it's not... so we have to work with what we already have.

There's a little bird outside that has become quite accustomed to us. It now hops into the container with one dodgy foot in search of crumbs. It hops right past me even as I type now. It has this weird problem where it is actually very territorial. When it catches sight of its reflection in the shiny underside of one of VSR2's pods it attacks it. It flies into its own reflection time and time again and we think it's silly. From it's perspective it might be watching us going out time and time again smacking into our own glass ceiling. Neither of us will give in. It's not about the ceiling of course but rather the desire to own the territory on the other side of it.

Our ratified record attempt starts in a few days. No wind is forecast. Maybe it's a good thing. Maybe we are being afforded the time we need to work on the problem without distraction. I still have faith that there are great leaps and surges of speed waiting for us once we gain the understanding. I just hope that mother nature gives us a decent shot.

Cheers, Paul.

28 comments

Slow speed sailing action... (video)

Fri, 26 Oct 12 13:53

If there is something to 'blog' about I will. Unfortunately we have had a long run of very flat weather and it looks set to continue. We are working through odds and ends but basically we need to keep doing runs to follow a process of elimination. We need to see what is stopping us from getting through the mid-low 50's. We doubt it is lack of power. We think it has more to do with an excess of drag.

Once most of the priority jobs were done, we took the opportunity to take a couple of days off. The days can be very long and relentless when the wind machine is on so you have to take these opportunities to get away from it all when you can. Namibia is an awesome country and it is always a pleasure just to load the car and disappear out back. They are filming the new Mad Max 4 film "Fury Road" out here at the moment. We often get members of the crew coming down to check out the boat so it was a real pleasure to have the team invited to check out their workshops. It is mind blowing what they do... and the cars... holy s**t! The Australian petrol heads are going to explode when they see these things. The cars will be the stars. As we drove out towards Brandberg mountain we drove right through the set and saw all the 'beastly' cars. In the landscape they were designed for... it was pretty impressive.

FURY ROAD... WELL THE C32 ANYWAY. A TOTALLY VOIDED LANDSCAPE WITH THE MAD MAX 4 SET WAY OFF IN THE DISTANCE. 'SHITE-RIDER' IN THE FOREGROUND!

So we camped and braii'd and hiked and stumbled across two bull elephants down a riverbed and basically enjoyed this beautiful part of the world.

I WAS JUST SAYING TO BEN HOW THE ELEPHANTS COULD BE RIGHT BESIDE YOU AND YOU WOULDN'T KNOW... WHEN WE HEARD A BRANCH BREAK. ONLY ONE THING DOES THAT. A MOMENT LATER TWO OF THESE FELLAS WALKED OUT.

... WHICH SENT US STRAIGHT INTO 'BABOON MODE' ON A ROCK WALL.

Late that night I sat outside the tent reading under a bulb. everyone was in bed and the campsite was pretty deserted. the sky was clear and a half moon was up. I noticed two low shadows about 20 meters away. It took me a while to realise what I was looking at. Nothing else moves like large cats. They were highly on edge and I couldn't move an inch or they would clock it. They walked around the perimeter of the light and down a dry river bed. I stood up and they melted into the bush. We checked the tracks in the morning and worked out they must have been cheetahs.

A very lucky encounter in the wild.

So we came back to Walvis Bay as I always have the fear that we are missing out on something. The forecast was very flat but we moved into standby mode just in case. This basically involves still doing jobs but being ready to sail on short notice in the afternoon if the wind goes against the forecast. It did this yesterday. We got winds over 20 knots at the container so headed across to speed-spot. The wind over there was gusty between 14 and 24 knots. We tried a run but didn't really expect to get going. I was surprised that we nearly did. It's a real trick at the best of times. We were close yesterday on a number of occasions but 'close' doesn't get the rabbit.

So we are on standby again today. It's already past 2p.m. here and we have very little wind. The rest of the week looks terrible. It is pretty unusual for this time of the year... and hence pretty frustrating.

WHAT IT MEANS....

Well, it means that we have had to book the WSSRC without actually seeing if we can break the outright record. We have to roll the dice. For a program on a modest budget like this one is... we try not to gamble too much. We have always hoped that we could demonstrate to ourselves definite record breaking runs before we call in the officials. I think you would all agree that it would be a pretty nice position for a project to be in. For a start, you could actually plan for it media-wise. Now if we do set records, we will all be seeing it for the first time before the WSSRC. It will be the real deal. We had to book the WSSRC well before now but we didn't have to book flights and all the extras yet. That time has now passed and we are committed all round. The record period will commence from the 1-3rd of November and run throughout.

Even now we are hoping to do some big runs before this period... but the forecast looks unlikely. It can change of course. We will be ready.

I have been reading and giving lengthy replies to all your comments on this blog-spot. There was a glitch there as we sorted out a spamming issue but I'm onto it now. There is a bunch of info in those replies for those of you who are into the details.

Here is the video... youtu.be/4OCkcuy-TfE

Enjoy.

Cheers for now, Paul.

4 comments

Video...50 knot + ride down Speed spot

Sun, 21 Oct 12 17:44

Following on from yesterdays run, here's the video as promised. Light winds today and for the next few days. Heaps of little jobs getting ticked off. We have the whole team working on the 'brick wall' of drag we seem to keep coming up against. We'll get there... and when we do... we'll probably keep going!

youtu.be/JBH0J1MyELk

Cheers, Paul

17 comments

Australian record and new PB for 500m... but...

Sat, 20 Oct 12 20:24

So I should be happier about setting a new PB over 500 meters of 50.98 knots. The peak speed was around 53 knots (1 GPS was over, the other under). The run started perfectly and felt super steady. Having an average so close to the peak shows this. VESTAS Sailrocket 2 felt great, the leeward pod was flying and the ride was smooth. Conditions were fantastic with winds between 25 and 29 knots.

I was hoping for big things but in all honesty they still didn't come. I decided to try again and reduce the inclination of the main foil even more. This would reduce the amount that the main foil pulls downwards and should allow VSR2 to ride higher.

There is still something big holding us back and it's not immediately obvious. As I was towed back up the course I pondered the fact that we had just UNOFFICIALLY beaten the Australian record and were within less than half a knot of overtaking Hydroptere to get the UNOFFICIAL title of fastest boat. I highlight UNOFFICIAL because although we used two GPS systems and are running on a well known course, we are not using the official TRIMBLE GPS timing system in the presence of the WSSRC who ratify these records. The numbers will be pretty close but we aren't that fussed as we are really still just developing the boat.

Whilst that last run will have generated a lot of data that should have been digested, the competitive streak in me wanted to at least knock Hydroptere off. Conditions were building over 30 knots so we hurried into another run before they got over the top. The second launch from the RIB didn't go so well. I will explain the whole launching sequence in greater detail later but for now all I will say that there is a phase where I sheet the boat in hard and stall the wing... and this is hard work for the RIB. When the wing stalls VSR2 tries to heel to leeward and this presses the leeward float hard. Some times we dip the leeward, horizontal wing extension. I wait to see if it comes up with the flap still attached. The windier it is the rougher it is and it all gets a bit marginal. Things didn't work too well on the second launch and I got stuck head to wind. I simply couldn't bear away and was risking damaging the leeward wing ectentsion trying... so I sailed VSR2 into the beach just a few 100 meters down from where we had left moments earlier. We walked the boat back up to our launching position. Helena confirmed gusts to 34 knots and steady winds over 30. Bloody typical. You set a limit and it gives you something just over. I was desperate to go again. I wanted to drink at least that triple rum and coke in a pint glass that comes with a new best peak speed. Beating Hydroptere would be pretty nice too... even unofficially. I decided that 34 was just too high. We shouldn't even be out in that stuff. The fact we can handle her in over the top conditions is a bonus that we can call on if pushed during record attempts. After attempting to launch in these wind strengths, 25-29 knots is a doddle.

So we waited and waited. The wing was up throughout. Helena called the wind strengths in via the VHF.

Every time it would look good... we would start to think it was dropping... and then the solid 30-34 knot sections would punch through. I was going through all the usual checklists of why we should go and why we shouldn't. Logic said we shouldn't, emotions said we should. I really wanted to go. Once again I had to concede to logic. We don't have to go, we have great data to look at, time is still on our side... andd as mentioned, we shouldn't even be out there in those wind strengths. The sun set.... so we lowered the wing and came home in the dark.

I have had a quick look at the data and it all looks good. I can't see why we are still stuck under that bloody low-mid 50 glass ceiling. We still have a few things to trim out and I'm sure we can gain a couple of easy knots... but she didn't feel like a 60 knot boat today. On the other hand, it was only our fourth run with new foils so maybe I'm being a bit hard. Righto, beer-O-clock. The Raft beckons. Hydroptere can have their title for another few days.

Cheers, Paul.

4 comments

Too little... Too much. Walvis goes Industrial strength. (Video)

Fri, 19 Oct 12 21:31

When we woke this morning it was obvious that Walvis was going to live up to its forecast. The sky was clear and the wind was already blowing from the SW early in the morning. Usually there is no wind that early and if there is any, it's from the North.

We had a couple of jobs that needed doing which involved composite work. You have to allow curing time for this and even when we accelerate the process with heat guns and fast resins... it's not instantaneous. Even with an over-the-top forecast I was keen to try and get a run in. I'm itching to see if we have the right solutions to get to 60 knots. Whilst Ben was mixing resins, Alex and I were calibrating strain gauges and resetting main foil pitch and inclination settings. We were climbing into MUSTO drysuits as Ben bolted the last necessary bits to the boat. The wind was building knot by knot and also swinging slowly to the desired SSW direction for Speed-spot. We were over there before 1 p.m. after going the long way around due to the low-tide shallows. The flamingoes mark out where all the low points are. It's great to have them back for many reasons. We didn't hang around at the timing hut. Helena was dropped off with the cameras and wind logging equipment and we pushed on up to the top of the course with VSR2 in tow. It was strong. Looking to the distant dunes upwind you could see the haze from all the blowing sand. We called Helena for a wind reading and she was getting 30 knots. I told the boys that 32 was my cut-off but to be honest, over 30 I was looking for an excuse to can it. Just as we released all the control lines to raise the wing, I got Alex to radio Helena one more time. Sure enough we had our 32 knots. It was pumping and we were only expecting it to go one way.

I canned the day. This time it was a 'no brainer'. I don't feel that we are ready to take on top-end conditions. VSR2 should only need 25-28 knot conditions to do her thing. She can sail in stronger conditions but really should only do so once all the systems are dialled in and the team are fully up to speed with handling her. Little problems get magnified into big ones on these days. At this stage we simply aren't under pressure to make bold calls. Tomorrow will be a good day so we can fight more on our terms then.

The day built had built. It was blowing hard by the time we got back to the container. Even though we didn't sail, I felt some sense of relief to put VSR2 away in one piece. I was happy with my call not to sail. I have become used to making bold calls in strong conditions. It's actually harder now to make the call not to sail as I'm my own biggest critic. The team spent the afternoon doing the odd little jobs that could be done in the shaking container. Dusty sand coated everything and a Hobie 16 tumbled onto a parked BMW in the carpark. Good old Walvis eh? So, as it stands, we are in good shape to fight tomorrow... and we are keen to do so. We have had one light day followed by one OTT day... now we need one just right. Patience is our game. Here's a great video by Ben 2 (Holder) which covers the last two days. Nice work Ben. Enjoy...

youtu.be/QAEYOS2UqcM

Cheers, Paul

1 comments

No joy today with patchy wind...

Thu, 18 Oct 12 19:56

We turned up at Speed spot expecting big things. I was feeling kind of nervous about the prospect of seeing VSR2 reveal her real potential. One of the things that makes you nervous is that she might also reveal other not so desirable aspects of which you are presently unaware.

Speed-spot looked great and we moved swiftly to the top of the course to get the wing up.

After a few little issues I was released by the support RIB and VSR2 promptly lifted up onto the plane without drama. I was still expecting a big run and sailed in towards the flattest water by the shore before bearing away. Normally you accelerate hard as you bear away but not much happened this time... and for the rest of the run. Everything just felt flat. I checked all the trim was as it should be. When I turned away from the beach to begin the stopping procedure the speed washed off quickly. I knew this meant light winds. Sure enough, once stopped, it felt pretty light. We pulled the rig down and towed VSR2 up to the timing hut to sit and watch the wind meter. We were getting 20 knot patches followed by 30 knot gusts. It just wouldn't settle down.

WATCHING THE TACKTICK WIND DISPLAY WAITING FOR CONDITIONS TO SETTLE.

We thought it would as we approached sunset so we made our way back up the course. A handling error whilst putting the rig up lead to a small breakage. Our day was over but to be honest, The wind had decreased and we didn't miss anything. We did learn some new skills today which will mean we need one less person to handle the boat. It was a simple thing really that we had included in the boats design but never used. It involves a simple forward weight on the wing for raising and lowering purposes in order to mass balance the wing. We were so busy adjusting the new sysytem that I failed to see a cleated line. As the rig was raised, the pole sticking out the front of the wing used to both sheet and hold the new mass balance broke. It was a silly error that was entirely my fault. Thankfully it wasn't on a critical day.

NO SHORTAGE OF FLAMINGOES THIS YEAR!

So that was that. No joy and frankly... a bit of a let down. the day had looked so promising. Tomorrow is forecast to be mental windy. Might be best to stay indoors tomorrow. It's the strongest forecast we have seen since we have been here. The sort of stuff the kiters crave. If we can, we will head out tomorrow. If not... then Saturday is our day.

Cheers, Paul

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Leaps and Bounds...

Wed, 17 Oct 12 12:04

We have looked at all the footage and had a good... but not yet overly detailed look at all the data we logged. I have also spoken to both Malcolm and Chris about yesterdays run, what it meant and what it shows us. We all agree that the back of VESTAS Sailrocket 2 was riding way too low. The rear float was often in contact with the water wheras it should be about 20-30 cm high. This means we had around double the amount of main foil in the water than we should have... and a lot of that isn't really dedicated to high speed sailing. I'm always happy to see big issues like that. We are aiming for high speeds here and we know we have to make big gains. It's all about what's in the water now. The wing was well sheeted in and the course was flat. As mentioned, 50 knots just doesn't cut it any more. So now I'm pretty excited about the next run. I hope today delivers although I'm sure one of the next days will. From our perspective it's about to get real interesting. The boat is good and we have a great team on location here. Alex and Ben Q both know this boat inside out. Helena knows the whole project inside out and Ben H is working like a beaver on all aspects of filming. That's his dedicated role and it's a great asset to the project as he can deliver high quality daily video updates... like this...enjoy...

youtu.be/1mH1bVvIPqY

We also have a mate from way back In Brad who has joined us for this session. Brad came down with us on our first ever runs with the Mk1 Sailrocket way back. We've all come a long way from those days. We laugh now how I started my first runs steering with strings from the rudder tied to my feet! Yep, a loooong way.

Cheers, Paul

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Straight into it. Over 50 on second run!

Tue, 16 Oct 12 19:01

It was a perfect day over on speed-spot today. The wind was 21-25 knots, the sun was shining and the tide was high. All the little sand-piper birds were sheltering behind the little sand-dune tussocks. They were bunched up there in little 'crowds' and after watching the recent Olympic sailing from 'The Nothe' bank in Weymouth, I kidded myself that they were standing on the grand-stand waiting to watch VSR2 do her thing. Let's face it, this is as close as you'll get to a crowd out here! We went straight into getting set up for a run and in general everything went smoothly. The day looked great and I was reading gusts of 23 knots on the Tacktick display and Helena was seeing peaks of 25 knots further down the course. I was confident we were going to see a fast run... or at least get good info.

The start up went pretty smoothly and sure enough, VSR2 broke free of all the low speed drag and got up on the plane. Ah, sweet release! I held a course into the beach to get into the flat water and then bore away down that magical mile. Everything felt fine. The steering was light and responsive and the acceleration came in bursts. We were easily well over 40 knots in a matter of seconds. Some times she would feel slippery and other times it felt like she was being dragged back... or was pulling drag. VSR2 seemed to break free again about 100m after the timing hut and surged up to a steady peak speed just before I turned away from the beach to give myself room to do a big round-up into the wind to stop completely. It was a solid run that ticked a lot of boxes. I was happy to see 50.11 knots on the small GPS to confirm what I would have guessed. The average was 45.57 knots over 500 meters.

RIDING QUITE LOW AT THE BACK HERE.

I can't get too excited about low 50's anymore. we have hit that speed many times with both boats and every foil we have ever used. The concept on which the Sailrockets are based has the power to pull any half decent foil up to this speed. We are openly targeting 60 knots now. I have been stuck under the low 50 knot glass-ceiling too many times and this boat/foil configuration is all about breaking through it. No complaints yet mind you. We did just hit 50 knots with our second run with a whole new foil. That run proved the following points...

1/ the smaller foils can get started in modest conditions

2/ the new foils don't seem to have any huge drag penalties and they must be well ventilated down their blunt bases just to achieve 50 knots. This already gives validation for the foil design path we have chosen.

3/ the new rudder gives great control and seems very responsive.

Now that we have the new SMD pressure sensor package on the foil which is being logged by tthe COSWORTH data logger, we don't have to do as bunch of runs to get the info that we want. We used to do runs to try and get the feel or do a process of elimination in order to go faster. Now we can simply look at the data and see solid information. You don't have to guess what is down those dark alleys anymore as you can turn the lights on. Doing 50 knots on our second run has put us a bit further forward than I was expecting. I decided to leave the perfect conditions on speed-spot and return to the Operations base at the Walvis Bay Yacht Club to digest the data we had just obtained. Already I have seen the following...

- We had relatively high pressures down the base of the foil i.e. we weren't being sucked back by low pressure 'cavities'.

- the rear pod was sitting very low. This means we weren't riding as high as we should be on the foil.

So now we have to start the real fine tuning of the beast. To do this we have to mount the new strain gauges on the rudder shaft. These tell us how much load is on the rudder at high speed and therefore how well balanced the boat is. From this we determine if we need to swing the beam and wing forward or aft. I wanted to see if the new small rudder did the basics before I wasted a £300 strain gauge on it. Ben has already removed the rudder stock from the boat and it sits in front of me now. We will be up first thing in the morning rigging VSR2 up on the lawn. We have to make the most of the still morning to do all the little jobs in preparation for another days sailing.

I'll leave it at that for now. We had a very good day as we jumped up the speed ladder in one bound with the new foil... but to have a great day... we need to see that 60! The greed for speed eh?

Cheers, Paul

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