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Android: Version 1.0.5, May 13, 2015
iPhone: Version 1.0.4, May 6, 2015



A alarm tone will sound in case of dangerous approaches. The beep pattern of the three warning levels in increasing order of importance are:

- -     - -     - -     etc.
(level 1/low danger/yellow/18s)
- - - - - - - - - - - - etc.
(level 2/medium danger/orange/12s)
------- ------- ------- etc.
(level 3/high danger/red/6s)

The first (low level) alarm sounds 18 seconds prior to a detected dangerous approach, the higher levels at the times listed above.

The alarm level is reduced by one for each 4m of additional lateral distance at closest approach. For example, if you're going to pass a boat/obstacle with 10m distance, you'll only hear a low level alarm.

Always use the TEST button before your training to check the volume level.

Please make sure to only use one RowingCAS per boat. Otherwise, nuisance alarms may occur.

When a alarm sounds, immediately look over your shoulder and visually identify the target. If you fail to establish visual contact, stop your boat.

System status

Every 30 seconds, one short beep or three short beeps will sound on muted volume. The meaning is as follows:
One short beep RowingCAS is operating normally
- - -
Three short beeps Error
Possible error states are:
  • Missing or inaccurate GPS position
  • Network or server connectivity issues
  • Missing permission to use precise location
In case of an error, additional information will show up on the Radar screen.

The radar screen

Please note: During rowing, you should primarily refer to the Audio alarms (described below) and not look at the radar screen. The display will go into sleep mode after a while as per your device settings while Audio remains active.

The screen shows up to five objects as little triangles (moving boats) or circles (stopped boats or fixed obstacles). If a dangerous approach is detected, the corresponding symbol increases in size, changes color, and an alarm tone sounds.

The own boat is shown in the middle of the radar in white. When it is stopped (speed over ground less than 2 knots), it is drawn as a circle, otherwise as a triangle pointing in the direction of movement. During standstill, alarms are suppressed.

Targets on the outer circle are 500m away. Targets on the inner circle are 250m away. Future versions will have a zoom function.

The radar uses your device's compass (magnetometer) in order to align the display with the relative position of the targets. A white triangle on the outer circle points to True North. If the triangle appears incorrect or jumpy, please calibrate your compass as described below.

When rowing upstream, speed over ground can drop below 2 knots. In the boat moving upstream, precision of the direction of movement is reduced and alarms can be suppressed.

Available options

Accessing the Options menu on Android

The Options menu is brought up by pressing either the menu button or by touching an icon with 3 vertical dots in the top right corner of the screen.

Accessing the Options menu on iPhone

Use the 'Settings' system application for 'Enable tracking' or the MENU button for other options.

Enable tracking

Check this option if you'd like your device to show up on the Live Tracking map.

Share my tracking link

Send your Live Tracking link to your friends.


Brings up this page.

The obstacle database

RowingCAS warns about fixed obstacles like buoys, poles, bridge piers etc. provided they are stored in the database.

Please contact us if you'd like to map obstacles in your rowing area.


The app requires:
  • Access to precise location information (GPS)
  • Full data network access
  • Android: Permission to keep the phone from going into power saving mode. This allows the app to run in the background.


How does it work?

Once per second, RowingCAS sends its position to a KTrax tracking server which cross-checks your course for potential conflicts with objects in your vicinity. In case of a dangerous approach the server sends the respective information to your device and an alarm is triggered.

The algorithm is carefully designed to warn only if a collision risk actually exists.

Audio volume control

Use the TEST button in RowingCAS to generate test alarms.
  • iPhone: Ensure that the ring/silent switch (left hand side) is set to "Ring". Select Settings → Sounds → "Ringer and Alerts" and adjust the volume. If "Change with Buttons" is active, you can use the volume buttons.
  • Android: Start RowingCAS and use the volume buttons. A speaker symbol appears next to the volume ruler.

I don't want to receive calls on the water!

You can mute calls and messages while RowingCAS alarms continue to sound:
  • iPhone: Activate "Do Not Disturb → Manual" in your settings and lock the phone using the sleep/wake button. Calls and messages are now muted even though the ring/silent switch is set to "Ring".
  • Android: While RowingCAS is not running in the foreground, reduce the ringtone volume to zero. A bell symbol appears next to the volume ruler.

Does it replace looking out?

By no means. RowingCAS can only serve as a wake-up call and additional safety net if you happen to miss a boat. Always keep a good lookout as described e.g. in this video posted by British Rowing.

Why should I use it?

A number of collision accidents happen each year in the water sports. Sometimes they end up in the news. RowingCAS provides an additional safety net in case a boat or swimmer goes undetected.

How should I wear or mount my phone on the water?

Remember that the acoustic signal is enough. No view of the display is required.

See also Rowing in Motion's mounting tips.

Why are you developing it?

A few reasons:
  • We like challenges and cool technology.
  • We hope it'll be useful.
  • It's a great demonstration of the capabilities of our Ktrax system.

Can it run in the backgound?

Yes. Audio indications remain active even if the screen is turned off. Please make sure that the audio volume is high enough using the TEST button.

Is it suitable for boats other than rowing boats?

Definitely. While rowers and kayakers will particularly appreciate RowingCAS because they're often facing backwards, the algorithm is perfectly suitable for sailing yachts, motor boats etc. We welcome reports about RowingCAS on boats other than rowing shells.

How do I calibrate my compass?

The warning algorithm of RowingCAS is completely independent of the compass values. Therefore, if you don't use the radar screen, you can skip the following procedure.

Make sure that there's no magnetic material near your phone. Notice that some phone cases use magnets to keep the lid in place.

Android: Dial *#0*# and select 'Sensors'. Rotate your phone around all three axes or 'wave' it until a '3' appears in the little black compass.

The movement is ("figure 8-wave") is described in this video. See also this forum post.

Power consumption?

In practical tests with various phones we've found an average battery life time of at least 5 hours. Please make sure that the screen is OFF for maximum battery life (rely on the Audio indications).

Always press STOP when you no longer need the app.

RowingCAS stops automatically if no movement is detected for 10 minutes or if the battery level drops below 10%.

We expect increased battery life with future phone generations and Android/iOS versions.

Does it work with my network provider?

Most likely it does. We're continually updating our provider and network information as we gain more experience during the beginning 2015 season.

If alarms generated by the TEST button work, then RowingCAS will also work fine under realistic conditions.

Data usage?

Watching a 1 minute video on YouTube typically uses much more data than RowingCAS uses in an hour.