The SailTimer API™ handles the Bluetooth 4 LE connection to the SailTimer Wind Instrument™. You can let the API run in the background. It hands off the wind data to other sailing, racing or chartplotting apps.

Logging in will also let you access new sailing innovations as they become available, like the Share button that gives you the option to crowd-source your wind data and view real-time wind maps to plan your tacking routes. You can Register the first time in the API or at Then you can simply log in to the API, and you won’t have to log in again for a long time. (Perhaps only if you get a new version or delete the app and then re-install it.)

The API is a toolkit that receives wireless wind data from the SailTimer Wind Instrument™ (, and reformats it to make it easy for other apps to display. We receive the Bluetooth 4 (Low Energy) transmissions in the API, so that other apps receiving this data would not have to each learn and build this code themselves. The API also converts wind direction from magnetic to true north, and converts the wind data to NMEA 0183 format.

You don’t need to understand the NMEA 0183 data, but it starts streaming in green letters so that you can see when the connection is made. This is the data that other apps use to display the wind speed and direction on a wind gauge, graph or tacking angles on a chartplotter. The MWD sentence is the standard sentence in marine electronics for wind direction. True (not apparent) wind direction and wind speed is shown.

You can add an identifier like your boat name to your Wind Instrument by clicking on the “i” on the line where it is listed. This is handy to do before multiple Wind Instruments start showing up in your marina, to identify yours. No-one else can see this, but it ensures that you are trying to connect to your own Wind Instrument. Once yours is connected, any others will not be displayed. There is also a Smoothing button on this panel, if the wind direction is jumping around a lot and you want to average it.

Also under the “i” is the Advanced button, for Compass Quadrant Fine-Tuning. Although your Wind Instrument was pre-calibrated at the factory, if you want to fine-tune the precise degrees for North, East, South and West where the Wind Instrument is mounted on your boat, there are innovative fine-tuning adjustments for wind direction under the “i” on the line of you

The API is designed to try to reconnect automatically if the Bluetooth 4 (Low Energy) signal is lost, or the next time you come back to the boat. But to connect the first time or if you need to re-connect, just press “Scan for Devices”, and then tap on the line for your Wind Instrument when it is found.

There is a Disconnect icon in the upper right corner that allows you to disconnect the Bluetooth and Location Services. That is handy when leaving the boat, or also if you want to save power in the iOS device and in the Wind Instrument when not in use. The Wind Instrument uses about 44% less power when Bluetooth is not connected. Similarly, your iPad/iPhone uses less power when the GPS (Location Services) and Bluetooth are shut off, either in Settings or with the Disconnect icon. Continued use of GPS running in the background can dramatically decrease battery life. This app may use your location even when it isn’t open, which can decrease device battery life.

*If you are getting the app and like this wireless technology, please help out other sailors by letting them know, with a quick rating on this version while you’re here.

What’s New

Version 1.3.6

• Layout improvements on iPhone.

Ratings and Reviews

3.0 out of 5
2 Ratings

2 Ratings

Simeoniii ,

Some issues using iOS 9

I've got an iPhone 5S iOS 9. The api screen for log-in doesn't quite fit. When logged in, and the WindInstrument found and identified, you can just barely see the top of the signal strength bars but the clickable area of the instrument button is hidden so you can't select it.

Works fine with my iPad Air 2.
Hope you will check this issue out.


JPH53 ,


I purchased the SailTimer wind instrument and have so far been very disappointed. After a long wait, my wind sensor arrived heavily scratched and with a battery that will only reach half a charge. The SailTimer API app eventually connected to the device but drops off frequently. Tech support is only through email and my technical questions emails have gone unanswered. Return policy is essentially a joke. Lots of promise on the design side but the company appears to lack the organization to make all the parts and pieces actually work.

Developer Response ,

We stand behind our products, and have also had dialogue with you via your posts in other places. Contacting our developers and expert sailors at Technical Support is the best way to get help. (As later determined, your email form was never sent in, but we do provide prompt 24/7 support to sailors worldwide.) Although you did not update your original comment above, we trust that things are better now now, and appreciate this explanation you sent in on August 7 2019: “The wind instrument is atop my mast and being used.  Your software is good and when the instrument is connected the overall system is very useful.”


Registration function broken

The registration function of the API app appears to be fatally flawed. After agreeing to the terms and conditions a pop up asks to "pick a color". There is no place to specify a color or select from a drop down list. You are just returned to the registration field entry page which puts the user in and endless loop. This renders the app useless. Using an iPhone 7 Plus and iOS 10.2


SailTimer Inc.
11.2 MB

Requires iOS 9.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
This app may use your location even when it isn't open, which can decrease battery life.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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