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Board » General Discussion » V070v3

Posted by 76Trombones Posts 362 Registered at 2009-08-03 18:04:56	2011-07-30 13:29:10 - V070v3
	There have been rumblings about upgrading our Volvo now that the next generation of boats are starting to appear. Still quite a few cards being held back, but we have some preliminary data for Puma, Groupama and Camper with more to come in August. I'm happy to do the final crunching, but in the meantime it would be great if we could set some of SOL's collective enthusiasm to the task of ferreting out relevant info: •Anecdotal data •Data points from pics showing instruments •Pics showing the nav station with the routing running (haha right, but sometimes they're sloppy) •The big one is to parse the tracker data. Either scroll manually picking off as many data points as possible into a spreadsheet, or trickier methods. There's not much point in trying to figure reaching speeds using this method, but scatter-plotting BS vs TWS for up and downwind conditions gives us a pretty decent overall evaluation. Tacking and gybe angles are also there (if you squint)... We have 3 months! Post away
Posted by RainbowChaser Posts 2656 Registered at 2009-06-14 09:44:50	2011-08-03 15:03:47 - Re: V070v3
	76T - it would be fab to have an upgraded boat before the next ocean race.. as you say.. we have three months!! Let's hope everyone starts data-gathering!!!
Posted by Sebensa Posts 70 Registered at 2010-10-06 14:50:36	2011-08-18 18:32:27 - Re: V070v3
	have been trying to ferret, with no results of any thing worthwile - will keep trying
Posted by 76Trombones Posts 362 Registered at 2009-08-03 18:04:56	2012-01-01 20:47:25 - Re: V070v3
	Raw data from the first two legs superimposed on our existing polar. Attachments Volvo70_2012.jpg (131.0 KB)
Posted by NZL_PaulR Posts 311 Registered at 2008-07-22 12:21:30	2012-01-02 06:47:21 - Re: V070v3
	The close hauled 40 to 70 TWA range looks reasonably close to the polar, but in the spinnaker 120to 140 range there is not as consistent agreement. This is all at first glance without any detailed comparision. My first questions is to ponder how much the sea state or tides/currents could have affected the actual results? Perhaps this is impossible to know or analyise and adjust for. Still it is a very interesting comparision. Well done & Thanks. If it breaks, it's not strong enough!
Posted by AGage Posts 411 Registered at 2008-12-27 10:31:57	2012-01-06 05:50:21 - Re: V070v3
	Very interesting 76... Paul - I would imagine that with enough data sea-state etc could be eliminated. I mean, if we had 200 data points for sailing at TWA X in TWS Y, there should be enough different sea-states and currents etc that they average out? Perhaps I am wrong though. Certainly some sea-state would be consistent, ie you usually have waves from behind when sailing downwind, and off the bow upwind. But that would be something we should include in our performance data? (as we don't have waves themselves in SOL) What should even out is the size of the waves. Sometimes they will be large and add a lot to the SOG - other times they will be much smaller (for the same wind) and contribute less. Seems to me inport data would help with this? I help develop the client interface for the best online ocean racing sim there is... __/)/)_/)__
Posted by NZL_PaulR Posts 311 Registered at 2008-07-22 12:21:30	2012-01-06 11:25:47 - Re: V070v3
	Aaron: I believe this is a simple summary. "In theory there is no difference between theory and practice, but in practice there is." So yes, lots more data could help, but eventually "paralysis by analysis" will occur. The Nexus Server & software can produce polars for you after some sailing. I'm sure other systems can as well, but I have not seen or done this myself. SOTP and looking outside the boat works for me, but a improving performance using a lot of effort and heaps of money would help!!. Still I do appreciate 76T's work and thanks for showing the data. If it breaks, it's not strong enough!
Posted by NZL_PaulR Posts 311 Registered at 2008-07-22 12:21:30	2012-01-06 11:27:51 - Re: V070v3
	However the sea states "average out", most of us are seeking excellence in sailing, not just an "average" performance, rather like sex really. LOL!! If it breaks, it's not strong enough!
Posted by 76Trombones Posts 362 Registered at 2009-08-03 18:04:56	2012-01-06 12:42:28 - Re: V070v3
	The data represents some 600 hours of sailing spread over 6 weeks and averaged over 1 hour periods (and 6, well 5... maybe 4 different boats), so it's a pretty good snapshot of average performance. The "average" performance is a moving target, but it's what should feed your navigation decisions (always looking out the companionway as well). There'll be another (dozen?) sets of data that are used as performance targets to put the spurs to the crew, adjust for extreme weather nastiness etc. Though sometimes you wonder... From Ken Read: “All of our routing software on board gave us an illusion that we could punch through that front,’’ Whenever statistics come up in sports (life, business etc) decision-making there's an argument that says that setting strategy based on anticipated performance is aiming for mediocre results. I don't buy it, but I think it's probably the way different people are wired - probably whole branches of psychology... I'd never say to my tiny pink crew that "we only need to hit 90% of our perf targets to make the critical move", but I'd likewise not make critical decision based on achieving 110%. In SOL, where 100% boatspeed is a given, I still try to allow room for error/fatigue/luck. Routing (or SOTP) can sometimes give you the idea that you can do things that are pretty improbable. Balancing the improbable and the impossible is a good chunk of the fun (and like swing-for-the-fences irl strategy, GREAT fun when it pays off). ANYways My take on the data vs our polar is that a) we're pretty close! We mostly knew that already, but cool to see. b) There are a few sail transitions that we could work into the polar to give us some more gears to play with (usual suspects close reaching and 110-130 depending on TWS) We're much too fast in some conditions, but have to balance against sailing gribs vs IRL and the way SOL handles weather, especially for ocean races.

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