The Dark Knight

Performance logging/polar comparison

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What tools out there allow you to log your performance and allows you to compare against polars? Post race..

I assume that Expedition & Adrena can do that, but they are very expensive and overkill when you just want to get a quantitative measurement of how bad you are when club racing.

Ideally a phone app would be best and simplest. 

 

I fitted a YD NMEA 2000 Wifi gateway on the boat I sail on, so my phone has access to NMEA which is obviously needed....

YDWG-02N_1024x1024@2x.jpg?v=1555604220

 

  

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Getting data collected is easy. 

Calibrating the instruments, so that the data is useful is harder

Making sense of the calibrated data, so that you can develop models from it harder still. 

Selecting what interval(s) of data are representative after calibrating takes judgement and at least in Exp, the "test" and Event inputs let you annotate when you are sailing for data collection, and then you can extract representative samples, and overlay on your sail chart etc. 

Sure you can in theory do all of it in Excel, but at what cost? 

Not sure of current retail on EXP, just paid a $250 upgrade to version 11 that was well worth it. 

My leisure time on board is worth a multiple of my salary,  the payback is less than a couple of days, saved and the other features are well worth the investment on their own. (We routed the 3BF inside SFBay...) 

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48 minutes ago, LionessRacing said:

Getting data collected is easy. 

Calibrating the instruments, so that the data is useful is harder

Making sense of the calibrated data, so that you can develop models from it harder still. 

Selecting what interval(s) of data are representative after calibrating takes judgement and at least in Exp, the "test" and Event inputs let you annotate when you are sailing for data collection, and then you can extract representative samples, and overlay on your sail chart etc. 

Sure you can in theory do all of it in Excel, but at what cost? 

Not sure of current retail on EXP, just paid a $250 upgrade to version 11 that was well worth it. 

My leisure time on board is worth a multiple of my salary,  the payback is less than a couple of days, saved and the other features are well worth the investment on their own. (We routed the 3BF inside SFBay...) 

Expedition costs $US1295 and given that I don't have a boat ATM, it would be overkill. Hence the wonder if there is a phone app

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+1 iregatta...but it really expects NMEA0183..

 

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I've seen raw data from a two boat AC testing programming. The scatter was...impressive. And that was not a budget effort.

I would be surprised how useful your own data collection would be, Its really hard to isolate a variable. Even simple stuff like wind strength varies due to how turbulent the wind is on a given day. 

But good luck with your efforts.

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On 1/28/2020 at 12:52 AM, The Dark Knight said:

expedition costs $US1295 and given that I don't have a boat ATM, it would be overkill. Hence the wonder if there is a phone app

it's easy to collect data - evaluating it, and then using it, is where the difficulty lies...

Expedition makes it easier to decide which data to use, and which not to use - you are basically looking for BSP at values of TWA and TWS, but you don't want to select data after, say, the TWS has just changed, or after the heading has changed, because the boat will not be at equilibrium.  Expedition's Stripchart makes it easy to plot all the data channels and computed numbers - like % of current polars - so you can easily see where are the best intervals to select your data points. It also averages the data over whatever interval you select - i might choose an interval of 5-10 seconds or more because of the scatter.

There is a lot of bad/unusable data that you want to filter out

Then there is the problem of TWS not being at the value of the polar curve you are editing - given all the unusable data.., how much usable data are you going to find where the TWS is _exactly_ , say, 12kts? probably none.., in my experience...  So, when your 5 second interval turns out to have an average TWS of 12.4kts.., expedition interpolates that to a TWS of 12kts before plotting it on or near your 12kt polar curve, and now you can edit the 12kt curve.

I'm not saying you can't do anything without expedition - just that it will be hard

 

 

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Assuming you had data, you could use Excel or similar to "qualify" it, 

something like require that the Apparent/Measured wind speed be "stable" in an interval, that the helm motion is limited to a maximum degree and that the heel be in a small range, and when the BSP was asymptotic use that interval for your polar.

Easy to do with the strip charts, probably not that hard to do with some basic scoring of adjunct calculation columns to identify potential intervals, though deciding what "stable" is is the hard part. 

 

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Have a look at the iPolar App for iOS. TBH I've never used it, but its by KND, who make all the analysis software used by VOR, IMOCA and SailGP campaigns.  So it should be the best of what you are looking for

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4 hours ago, Miles said:

but its by KND

i've been thinking of getting their windows polar software - Polar Manager.., but by the time you get the other programs you need to use with it, it becomes kind of expensive

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On 3/26/2020 at 3:06 PM, us7070 said:

i've been thinking of getting their windows polar software - Polar Manager.., but by the time you get the other programs you need to use with it, it becomes kind of expensive

It depends on the use case, to me the money I spend with KND every year is worth every cent, compared to the number of days I would spend doing this kind of analysis in Excel. 

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On 3/29/2020 at 2:24 AM, Miles said:

It depends on the use case, to me the money I spend with KND every year is worth every cent, compared to the number of days I would spend doing this kind of analysis in Excel. 

What Miles said.  Yes, KND is really fucking expensive  - Cyrille, are you listening? - but it's analytical approach is fundamentally different.  Expedition is really great - you all know that - but it is a nav tool, not a systematic data analysis tool.  Horses for courses.

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Spend time on the boat and make the table over time.  Better than any software that is trying to think for you, and often software assumptions will be significantly off, especially if the instruments are not spot on- when are they ever spot on unless you have a full time pro on it?  Get a polar from one of the VPPs like ORR or ORC- ORR-EZ for not too much money.  Compare that VPP to the table you compile. 

I use Sailgrib on android with a waterproof galaxy tab active tablet which is a friggin steal as far as functionality v. cost.  Sailgrib has a gazillion polar tables built in from stock VPPs.  I have compared a few of the VPPs from Sailgrib to boats I have sailed on, and they were very good.  If your boat is not in there, chances are there is one that is very close, unless you have some mega custom way outta the box type thing.

I've used Sailgrib side by side with expedition on the last 2 ocean races I did, and the routing was nearly identical.  No I don't work for them, I am a paying customer.

 

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