SailTimer API™

39 reviews
Content rating
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About this app

The wireless, solar-powered SailTimer Wind Instrument™ transmits wind speed and direction from the masthead. An API is a digital toolkit; this one receives the Bluetooth Low Energy (also called Bluetooth 4) transmissions from the Wind Instrument, does some conversions, then sends the data to other apps for viewing. See the innovations and features of the Wind Instrument at

Version 2.0+ of the API includes advanced new Bluetooth technology for fast, reliable connections to the Wind Instrument across most Android devices up to Android 10. (For later versions of Android and the "WMM Edition" of the Wind Instrument since April 2021, use the "SailTimer API-WMM" app.) Read on for other features of this app…

Add your boat name to your Wind Instrument (only visible to you), to be clear that you are always connecting to your own device.

The API remembers your Wind Instrument and reconnects automatically next time you come back to the boat. If you lose the signal, the API will also reconnect automatically if it is open.

The circular Disconnect button on the top bar is handy when leaving the boat, or if you want to save power in your mobile device and Wind Instrument when not in use.

The API maintains the wireless connection to the Wind Instrument when in background, and even if tablet/phone screen is turned off to conserve power. When API is open, tablet/phone will not go to sleep by itself.

The Sharing button allows crowdsourcing of live wind maps, which can still update when the screen is turned off. Go to to check wind conditions on any Wind Instruments around you, and to view, share and replay your tacking routes and wind conditions.

Magnetic declination is calculated in the API based on your GPS location on Earth, to convert Magnetic North wind direction to True North reference. Compass fine-tuning: not needed in normal circumstances, but this advanced option could fine-tune precision in magnetic wind direction.

Use this API with the SailTimer Wind Gauge™ app or with other navigation, wind gauge or performance apps that support the SailTimer Wind Instrument™ ( The GPS in your device needs to detect some change in your location before data starts to be sent, which may take a minute or two. The API sends official NMEA 0183 sentences for wind direction (MWD) and wind angle (MWV) to other apps for viewing.

Because of the variation in hardware in different phones/tablets, some may connect faster than others. There are two steps: the initial scan to find your Wind Instrument (usually fast), and then the Bluetooth connection with the phone needing to connect when the Wind Instrument advertises (wakes up and listens) that it is available to communicate. If your device is not one that connects immediately, just start the connection and set it down for a few minutes, getting other stuff ready on the boat. Then it will be connected when you come back. If not connecting, reboot the tablet/phone and open the API and the connection should be faster on most devices.

There is new security to protect the transmissions, which may occasionally mean that the initial connection is immediately dropped, if the timing to complete the entire handshake wasn’t sufficient. But once it connects for more than a few seconds, it will stay connected. Don’t be surprised to occasionally see the connection drop the first time. That is normal, and is caused by the security protocol in the transmissions.

The specifications of your device may indicate if it uses Bluetooth 4, which is supported on Android version 4.4 (KitKat) and newer. If you need to check what version of Android you have, it is in Settings > About Phone.

End-User Licensing Agreement:

There are How-To-Use pages and FAQs at If you have a question or feedback please email We’re here to help.
Updated on
Sep 24, 2020

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
This app may collect these data types
Data isn’t encrypted
Data can’t be deleted

Ratings and reviews

31 reviews
Yiannis Costopoulos
March 9, 2023
The app connects to the device, I can see battery level, signal strength, temperature, but there is no wind direction or speed. I tried in combination with the other SailTimer apps, to no avail. I am sending the device back. What a disappointment!
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SailTimer Inc.
March 9, 2023
Hello Yiannis, Please contact info at for prompt technical support. We only get 350 characters to respond here. There is no need for disappointment; we can help you. :-)
Chris Cumming
July 5, 2021
Can't get it to work when I hit wind gauges button bombs out of app. Have three apps android one only one to give me any joy but no Wind speed or course. Got it to work. Had to reset Bluetooth. Thanks tech support were patient but had to. Figure out most of it myself.
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SailTimer Inc.
June 25, 2021
Chris, Thanks for providing feedback, but this is not the place to get Technical Support with 350 char limit. If you contact we can provide quick and friendly help. In this case, you are using the wrong app. If you check the page that came in the box, you’ll see: “2. Download the free SailTimer API-WMM app.” Happy sailing.
A Google user
October 10, 2018
Water proofing failed on sailtimer, killing the solar panels. Customer service would not repair a "sealed " unit less than a year old. $349.00 paperweight. Do not buy sailtimer. Battery died, followed the use instructions exactly. Would not hold a charge. Exasperated with customer services, will not entertain the possibility they may have shipped a bad unit. Ordered July 2016, received August 2017, kept in the sun for the winter with blue cap on, now dead. Tech support is quick to respond, with corporate motto "you didn't charge it properly." Hit or miss. If it worked, it is a great idea and price.. do not buy.
2 people found this review helpful
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SailTimer Inc.
April 8, 2019
Your comments are not about this app, but we’ll try to clarify in the space available. We don’t have any record that you got in touch about any leak when your model was less than a year old. But we can help with guidance or warranty coverage if you contact Technical Support. The new Wind Instrument RB™ has a 2-yr warranty and Replaceable Battery.

What's new

• Streaming data is shown in green text as NMEA 0183 sentences arrive from Wind Instrument. Makes it easy to see if you have a Bluetooth connection, and to check the incoming data if needed.
• Updated for Android 10.