CrewWatcher Bluetooth MOB Alarm System

By Tom Burden, Last updated: 7/22/2019

There's an app for that!

Example of mobile app with crew overboard

Get connected to stay safe; CrewWatcher uses a small beacon and your smartphone to alert you if someone in your crew falls overboard.

The Smart Boat app, CrewWatcher, lets a skipper know if someone in your crew goes overboard. The CrewWatcher system is the best and simplest application of crew-overboard systems we've seen yet.

Just Small Beacons and Your Smartphone

CrewWatcher has only one component, a small, Bluetooth beacon. Each person onboard attaches the beacon to a strap within their life jacket, preferably as high as possible.

Crew member clipper a crew watcher beacon to his life jacket

Crew member clipping a CrewWatcher beacon to his life jacket.

Crewwatcher beacon clipped to the collar of a dog

Every member of your crew can wear one!

The other component is your mobile phone or tablet equipped with the CrewWatcher iOS or Android app you have downloaded. No cellular service is required to use or set up CrewWatcher. Set the system up by simply holding the beacon against your phone and it will pair automatically using Bluetooth 4.2. This is the low energy variant of Bluetooth which has increased range, up to 200 meters. After pairing, you can assign a name to each beacon. Each smart device can watch up to five beacons.

How It Works

Every second, the phone checks to see if the beacon is in the water and if the connection is lost. If an activated beacon detects water or loses its signal, the app will automatically sound a “man overboard" alarm within five seconds.

The alarm gets increasingly urgent over time, even if your phone is set to silent mode. In the confirmation screen, you are presented with the three most urgent actions as a reminder: 1. Start the Rescue by pressing the "Rescue" button on the screen; 2. Throw a Life Buoy or other flotation device; 3. Send a DSC Distress Alert using your VHF radio. In addition to the alarm, your phone or tablet will vibrate and flash its camera strobe light.

Once you hit the onscreen button confirming the MOB alarm, your phone will display a compass rose and pointer, guiding you in the direction of the person in the water. It also displays bearing to MOB, distance, time since MOB, and the lat/long where the MOB went overboard (point of loss). When your boat has returned to the "point of loss" where your crew member splashed down, CrewWatcher will try to reconnect with the beacon's signal. When it reconnects, a "Signal Found" screen tells you that the MOB is nearby. If it doesn't find the signal at the point of loss, it guides you to an expanded search area (to allow for drifting) and where you are in that area. As long as your overboard person's beacon is above the waves, it will continue to try to reconnect with the phone or tablet.

Battery Life

Batteries in each of the small beacons are rated to last at least three years. Battery life varies depending on hull material, with steel and aluminum creating more signal resistance, lowering battery life and slightly reducing the range (if your phone needs to receive the signal through the deck or hull). The manufacturer estimates real-world battery life at up to nine years depending on use. The battery is only active when the app is connected and watching. Also, the app shows the beacon's battery percentage and it updates every time CrewWatcher is enabled.

Other Uses

CrewWatcher is also useful as a high-water bilge alarm with its water-sensor. In addition, the signal separation feature alerts you if your towed or tethered dinghy separates from your boat.