Sail-World.com : Vestas Sailrocket 2 - Last big push before record attempt begins
Vestas Sailrocket 2 - Last big push before record attempt begins
From the Vestas Sailrocket 2 team in Namibia*:
'Well I'm happy to say that we are back all safe and sound after going sailing on perhaps our windiest day.
We did two runs today. I wanted to get back in the swing of sailing in punchier conditions. The first run was a little uneventful with a peak around 46 knots.
The wind felt like it was going to build and was still a little west. This makes the course a bit more downwind which in turn doesn't allow us to build up as much apparent wind as we would like. I spent a large part of the run playing with the new flap control line on the wing extension. This is there to control the height of the leeward pod. It did seem to be one string too many in there and quite hard to get right as the boat is rarely in a steady state as it surges and sags whilst bi-secting the gusts. I have the mainsheet in my right hand which is also steering... and now the leeward flap control (let's call it the 'roll control') in my left hand. I really do very little steering although I need to pay attention to what is ahead of me as well as what the wing is doing. The workload is increasing in there so it might be getting time to fill that back seat in earnest. VESTAS SR2 felt as stable as ever although I never got the real solid surge that means big numbers. When I bore away at the end of the course, the speed dropped off quickly. This usually indicates that the wind is indeed too aft. Whilst we put the rig down we got some solid gusts. the day was definitely building. The peak speed was only 46 knots and that in itself wasn't very satisfying. It's hard to know what the wind was blowing as it can vary from 22 to 29 knots and swing through 20 degrees. Fortunately TACKTICK had sent us a new wind wand and we had that in place on the actual wing so I'm expecting some pretty handy data.
Seeing as the run went off with little drama, I felt confident to go up the course for another one as Helena called out gust peaks of 31 knots. It was time to go for a big run. It felt much better to be on the water in a sailing frame of mind rather than sitting around looking at a wind readout debating the pro's and cons. I knew this would be our last chance before the record attempt starts in 6 days so was happy to give it a nudge. We stopped in at the timing hut on the way past and I double checked the wind data. I didn't see any 30 knot gusts whilst there but I saw lots of 29. It was definitely getting windier. We headed to the top of the course and rolled straight into a run. Helena was calling out gusts to 32 knots. This was getting pretty wooly but the boat was behaving itself. We had found some rig setting where it seemed to like to sit before the sailing starts.
Once released from the support RIB and in a good position to start a run, I began going through the procedures. For some reason VSR2 stubbornly refused to bare away. I oversheeted to the max but she wouldn't turn. She was sliding sideways pretty rapidly and the leeward pod was dipping hard. The whole horizontal wing extension was being pushed onto the water as the stalled wing put a rolling moment onto the boat. There was alot of wind. I pushed hard in the design phase to keep that wing high out of the water for just such an occasion. The lower the wing is, the better it works in ground effect... but this was the reality of sailing in rough, top end weather. Every time the designers creapt the wing down, i would push it up again. We all want speed and efficiency but then I have to live with the real practicality of the whole thing. Overall this boat is just so much better than the first boat on this front. VSR1 would have simply sunk today.... just before hitting 53 knots in 5 seconds and about 200' high!
Finally a wave combo helped the nose turn away from the beach and we dropped into mode. The start up was quick and the acceleration came fast. There was one surge during the bare away onto the course which was remarkable. maybe it is when all the apparent wind lines up with the fuselage. I don't know... but I'll look into it. There was no doubt it was a fast run. It felt very solid and steady. The roll control seemed to work fine. the new mainsheet with the HARKEN micro blocks is an order of magnitude better. VSR2 felt fast with a couple of big spurts in the run I started a turn downwind to burn off speed. She burnt off some speed but was also sailing out into lumpier water still doing well over 40 knots with the wing eased. I was rapidly running out of options other than a big right turn into the wind. This is a big, bold and fast manoeuvre that you have to commit to. The pod literally flew as it went swinging round the outside. The boat seems to accelerate into the turn as it briefly hooks into the apparent wind again. As the fuselage is skewed twenty degrees to the direction of travel, you get the impression that you have turned past head to wind. The beach comes up quick and you have to keep turning hard until the boat just stops. then you have to quickly lock the rig off and trigger the main foil release to stabilise everything. All the while still draining the adrenalin from your system.
It felt like a big run. It felt faster than before. I noted that the yaw string was still well off being aligned with the fuselage indicating that we were well off being as efficient as we were supposed to be. That to me is not a good sign.
The numbers just in are as follows...
Max speed (doppler)- 52.13 knots
500 meter average- 49.22 knots
100 meter average- 51.6 knots
Whilst 52 plus knots would normally be a good speed, this was top end conditions and I expected more. I really wanted to be at least in the high 50's or even get a peak at 60 in these sorts of winds. Hmmm... it would seem that we may still be up against our old speed-sailing nemesis of speed sapping cavitation. We may be getting cavitation on the leading edge which is not joining up with the ventilation at the back of the foil i.e. we don't have a 'super-cavity'. We all think that we still have a lot of attached flow on the back of the foil. This is not so bad, we simply have to start playing around with ways to trip the flow off the back and try and induce this super cavity. In many ways todays sail was really good. We sailed relatively comfortably in honking winds, we got a clearer picture of where we are performance wise and we got a heap of data off the boat to help us get sorted. Sure, of course I want... I need to see the big numbers to be confident of beating the kiters... but they will only come with understanding. It seems that pure balls and luck won't be enough.
It's always a pleasure to put the boat away after a big day like this. I'm once again sending this from a rattling container. Tomorrow is going to be a bit mental wind-wise before a light forecast for the rest of the week.
Well, the original plan was to be breaking record speeds before the record attempt started. We aren't there yet. If we do hit those big speeds then it will be done for the first time before the eyes of the WSSRC official. I was really hoping to nail it today. To at least top Hydroptere's speed would have been a good start. Oh well, not to be. Like I said, we gave it a nudge. If we're not ready, we're not ready. We still have a few tricks up our sleeve. We'll get there.
Cheers, Paul (Larsen)
Mon, 7 Nov 11 18:17
Well we have just finished doing the full assembly of Vestas Sailrocket 2 and she now sits quietly beside us under her soft cover. Nick has finished fairing the repaired main foil and it has been fitted to the boat and the beam repair has had her first coat of undercoat in preparation for tomorrow's top-coat.
We are pretty much ready for action.
*Vestas Sailrockt 2 is in Namibia attempting to break the World Sailing Speed record. The official WSSR record attempt begins on the 18th November 2011.
On the 25th October Vestas Sailrocket 2 sustained damage when pilot Paul Larsen encountered a flock of cormorants, cleared them and accelerated. However VS2 stalled and damage was caused on the way back in from the aborted run.
On November 3rd VSR2 completed a full 60 knot-plus load test on the high speed foil which passed without a problem. Ed
More info about the Vestas Sailrocket 2 team here
by Paul Larsen
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9:13 AM Sun 13 Nov 2011 GMT
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