DC Calculator

I have known of this small tool for a while now, but not being the author of this tool could not (until now) say anything public about it without the author’s consent (which I now have). I have seen a number of chat comments and received a few emails about the possibility of a tool to help calculate the time to use for a DC, especially those for rounding marks etc as one desires not to be too far over (and definitely not early in the case of land involved!)

Well, this tool called “DCC” for ‘Delayed Command Calculator”, does exactly that.

A word of caution though: this tool DOES NOT make use of wind data other than for the current moment. So if you are setting a DC in conditions which are rapidly changing, or perhaps a DC for many hours into the future, use with care – and please don’t blame the author (Schakel) if a DC you set based on his tool puts you aground – it is an aid, nothing more, and discretion is needed.

I wont post screenshots or any instructions here, as Schakel has already done that (and besides, thats not my job 😉 )

But you can read all about it, and find a download link here.

Actually I have found another use for this tool as well. Often we may ask “How fast is 76Trombones going over there?” (or whoever is of interest at the time). Well, of course brainaid’s NMEA proxy coupled with NavMon (or Expedition so I am told) will tell you this information, albeit with some small error. But this setup is not necessary, just for a quick answer. If you click the boat under examination in the boat list (within the SOL client), this will centre the boat and display its track. Now you can use the ruler tool, to get a pretty accurate reading for their heading, by simply extending out from their track. And of course you can get the current TWS/TWD bt placing your mouse over the boat, and it is displayed in the top right corner of the map. So now all you need to do is enter this information on the ‘Boatspeed’ tab of Schakel’s DC Calculator, and viola! you will see the boatspeed of the boat under examination computed for you, from the polar – as is noted on brainaid’s site that SOG can only be estimated from the data available from SOL.

Of course, you will need the polar for the current race, but you need that to make ANY use of his tool at all.

Also, even though Schakel’s tool does come with a comprehensive range of polars, I would recommend making sure you have the latest one (in CSV format) from brainaid’s site, as they can and do change – IMOCA after Leg One is thelatest example of a race that changed polars. Plus it is only a small download and can’t hurt to ensure you are using the most up-to-date data.



NOTE: I am considering writing something very similar but embedded in a Web page similar to brainaid’s toolbox, I just have to learn a bit more about writing web applications – as this isn’t my typical area of programming. So for a ‘self-tutorial’ I thought I might start with a DC Calculator and VMC computer. So non-windows users can have access to this tool aswell – also, there would be no need to get a polar file from brainaid’s website, as I can pull all the same data out of the race file from SOL, so is always the right polar data. Please note though, I said only ‘considering’.
  1. #1 by Schakel on March 27, 2011 - 14:01

    :LOL: Aaron, I did that all the time, looking at other’s boatspeed, I mean. I learnt a lot about what angles they use.

    Philip (Schakel)

    • #2 by AGage on March 27, 2011 - 14:31

      Well I should have written that I didnt exactly think it was an original usage 😉 Just you didnt mention it in your blog post…

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