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Board » Technical Discussion » Isochrones

Posted by
Irukka


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2010-12-27 22:17:29
2024-05-28 13:51:29 - Isochrones
Hi SOLers! I have seen the isochrone calculator section in the Tools panel available under the Misc tab of the client.

I couldn't find any information about it in the manual, and I was wondering whether there is any other source that covers it.

More specifically, it would be nice to know how are the isochrones calculated for both the COG and TWA modes, and perhaps some practical tips on how they can be used during a race.

Alternatively, if some of you used them and want to share your impressions or strategies regarding those, it would be more than welcome!

Fair winds!
Posted by
Tacktician


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2024-06-24 14:49:05
2024-07-03 18:13:36 - Re: Isochrones
I'm quite new to SOL and I don't use the isochrone tool much so take this with a big heap of salt.

I also haven't seen any documentation on the isochrone tool. My impression is it shows where you'd be in X hours if you immediately make an order to COG Y or TWA Y and issue no further orders. Each curve shows one value of X (you can adjust the spacing between Xs with the "step" menu) and many values of Y. It probably tries hundreds of different values of Y to show a smooth curve. It seems to ignore the fact that you can't travel over land. It's similar to the polar chart but uses forecasted weather not the weather right now.

It can give you an approximate sense of how fast you can travel in different directions. In open water (land no factor) your predicted travel times using the DC-enabled course predictor should be at least as fast as the isochrones predict if you choose course changes well. Over short distances (~1 hour) you'll only beat it significantly in directions where the polar curves inward and you need to tack, gybe, or hop. At longer distances its accuracy will vary but it's more accurate than I expected. Looks like I can beat it by 0-20% usually.

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