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10/04/2017 2:12 am  #1


Getting up to speed through data

Hello, I'm in the process of buying a new (used) raceboat. With it there are extensive amounts of logs from expedition over some years. I'm wondering; is there any tools or exp features that can help us getting up to speed faster using all this data?

Questions could be anything from getting a feel of angles used in different conditions to figuring out what canard and keel angle settings to run. Or just gaining an understanding of the performance to expect in general. Input on what to look for in these logs is also appreciated.

I was about to start writing some code to help me analyze logs (as I have lots of time to spare nowadays), but figured I'd ask in the forums first.

Thanks.

Last edited by lutt (10/04/2017 2:14 am)

 

10/06/2017 5:52 am  #2


Re: Getting up to speed through data

In addition to logs, do you have sail chart and Polars ?
They would represent the distilled data.

You don’t mention the type of racing, open water or buoys you might want different analyses

Things to look at for buoy racing would be acceleration out of tacks, rate of turn & rudder angles to give fastest tack/acceleration vs wind and sea state.

If you have sensors on the rig as well as keel, then getting those values for typical/best results would be a start in a tuning guide.


Semiconductor Development Engineer, Retired Viticulturalist, Occasional sailor
"Lioness" 1962 Hinckley Bermuda 40 Custom Yawl
 

10/06/2017 7:44 pm  #3


Re: Getting up to speed through data

Noting Sheldon's comments above, before you spend time on the data - I look at a fair bit of this material - two things:
1. Make sure the instruments are measuring accurately, and were doing so at the time the logfile(s) were created;
2. Go sailing and decide what questions you want answered through the data.  Data analysis works well when asked pointed questions.

 

10/07/2017 4:02 am  #4


Re: Getting up to speed through data

Thanks Sheldon. Yes, there's polars and sail charts as well. But not sure how well the polars are maintained, while the sail chart is up to date and well maintained. I see polars as one answer to the formula, while sail charts are one of many parts to get answer of the formula.

There's load cells as well. I figured I'll use the data to make and print out a table of settings to put up for trimming runners.

DuncanR wrote:

Noting Sheldon's comments above, before you spend time on the data - I look at a fair bit of this material - two things:
1. Make sure the instruments are measuring accurately, and were doing so at the time the logfile(s) were created;
2. Go sailing and decide what questions you want answered through the data.  Data analysis works well when asked pointed questions.

What do you use to look at this material? Excel or a specific BI tool? If there's no holy grail to do this, I figured I'd make something that can make the answering a bit quicker while being out on the water.

Last edited by lutt (10/07/2017 4:15 am)

     Thread Starter
 

10/07/2017 7:32 am  #5


Re: Getting up to speed through data

Excel is generally a good start, there are proprietary tools from KND etc if you want to invest.

I often take the data files to my office and use JMP from SAS institute as it has some nice time series functions and I have a triple monitor that allows me to spread out a strip chart to where I can see it.

​Perhaps I misconstrued your intent. I thought you wanted to review the boat's historical data, and get a start on tuning rig and coaching helm based on those results.
In terms of on the water analysis:
​I don't do it, as I am too busy driving, but rather try to pay attention to my targets and lay down a good "test" for a minute or two (as Lioness is slow and heavy, we take a while to get to equilibrium)

I go out with a set of goals, to try to collect calibration data, or to work on upwind tuning and try to pick days and courses that are conducive. Since its a 90 min drive to the boat, the goals tend to subordinate to the conditions and crew. Often times I do this single handed with the Autopilot driving for consistency, as we are a very modestly funded and staffed team of amateurs mostly out for fun. (Campaigning a nearly 60 yrs old CCA yawl should be fun, or why do it?)

Today we are heading our for a few hours of practice with the Asymm, a sail I haven't hoisted in years, due to other focus. Figured we should shake the spiders out of the bag before we hoist it in anger next week in the "Octoberfest" race and see how many Lederhosen we might need to buy, to gain the 3sec/mile credits.

​It's also "Fleet Week" the annual ritual of watching an airshow while bobbing around Alcatraz, forecast on the Estuary is 5-10 kts, (perpetually) so we will be doing more practice than data collection, but I will still fire up Exp with the NMEA REMOTE & VentusPro hooks to confirm it all is working, and to have a walk about display.


Semiconductor Development Engineer, Retired Viticulturalist, Occasional sailor
"Lioness" 1962 Hinckley Bermuda 40 Custom Yawl
 

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