SailTimer Wind Instrument on this coach boat in Southern California, for measuring True Wind Speed & Direction while whizzing along after the 49er in the background.

True Wind Calculator in App
+ Wind Instrument early summer sale below

A new version of the SailTimer Wind Instrument RB™ was released this spring. With all-new firmware in the electronics, it required a new API app on Android and iOS to receive the Bluetooth transmissions. The newest version is available on Android now, and the new version 1.4 should be approved and in the iOS app store tomorrow (28/6/21). For manually calculating or checking True Wind Direction (TWD) and True Wind Speed (TWS), a hidden button was put into the API. This is not needed to use the Wind Instrument, but you may find it interesting to see how it is used by race officials, coaches, and for the crowdsourced wind maps that we continue to develop (more about that in the coming months). Here is the secret of where to find the hidden button and how it works...

You don't need to be able to decipher the green text in the screenshot below, but it is an easy way to see if your Bluetooth data is streaming. Seeing the incoming data may also be handy for troubleshooting. And now you can use it to convert Apparent Wind (what you feel and measure when the boat is moving) to True Wind (the actual wind movement, independent of the boat's movement - the same as in the marine weather forecast).

To open the simulator, connect to your Wind Instrument then long-tap on the beige wind cup icon in the upper left corner (see photo below). To stop, double-tap on the wind cup icon, and you'll see a confirmation message.
Enter values in the 4 boxes to systematically check True Wind Speed & Direction.

To view the resulting TWS and TWD, you can interpret the green text (NMEA 0183 format) or can view True Wind in a different app. If you wish to interpret the lines of green text for wind direction, page 12 from the Owner's Manual shows the format for the lines with True and Apparent Wind Direction/Speed.

It is usually tricky to test TWS and TWD, while controlling your movement and trying to test different wind angles and speeds. When you are stopped, True and Apparent wind should be the same (although True wind may sometimes move around because of the accuracy limits of GPS). This simulator allows you to do systematic conversions, without going out on the water. Useful for verifying data and troubleshooting, and also for training.
Wind Instrument on RAM mount, on T-top of a Triumph 19’ center console. Transmitting to iPad to get True wind direction for mark-laying. (Photo credit Dave MacKinnon, Principal Race Officer - Whitby Yacht Club, Ontario Canada.)

Setting marks for races is another reason for knowing True Wind Direction. And of course, all racers want to have good wind data on all legs of a race. Crowdsourced wind maps can help with that. They also need True Wind for comparing high-resolution wind measurements with the marine weather forecast.
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The wireless, solar-powered Wind Instrument RB™:  Replaceable Battery in the nose cone. Works with lots of apps. The only anemometer in the world designed for sailboats, remaining equally accurate when sailing along heeled over. You can even raise it without lowering or climbing the mast. Transmission range 280 feet (85m). Now $100 off, with early summer sale: $449.99.


49er photo above used with permission.

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