BoatyAlarm

What BoatyAlarm is

BoatyAlarm is a free drift alarm for BVI moorings. Over 600 moorings in the BVI are pre-mapped in the app with each mooring’s actual GPS location. When you tie up, the app knows where the mooring is and draws a geofence (a “safe zone”) around it. If your boat drifts outside that zone, the app alerts every device on your crew’s shared trip immediately.

Most of those 600+ moorings sit outside the BoatyBall program. National Park, dive and first-come moorings are mapped too, because BoatyBall isn’t in every bay and we would rather every boat in the BVI had an alarm running than only the ones on our balls.

However carefully a mooring is looked after, it can be damaged by the boat that was on it an hour before you arrived — a prop strike on the pendant, a chafed line, a shackle worked loose. We get reports of damaged balls every day. No inspection schedule catches that, and an alarm is what tells you at two in the morning.

BoatyBall strongly recommends running some form of drift alarm on any overnight mooring. BoatyAlarm exists to make setting one as easy as possible in the BVI — no configuring the geofence from scratch each night, no fussing with coordinates. Tie up, tap the anchor icon, done.

Getting started

BoatyAlarm is a separate app from BoatyBall — you download it once, then sign in with your existing BoatyBall credentials.

That’s it for setup. From here, you’ll create trips and set alarms as you go.

Trips: sharing the alarm across your crew

A “trip” in BoatyAlarm is a shared session that lets multiple devices monitor the same boat. One person creates the trip; everyone else joins it. When the alarm goes off, everyone on the trip gets notified — not just the person who set it.

Creating and joining a trip

• The first person on the boat opens the app and creates a trip from the menu.
• Others must join that trip if they want to help monitor. They can join two ways: scan the QR code shown on the creator’s device, or manually enter the trip code.
• You can be part of multiple trips at different times, but you can only actively monitor one trip at a time.

Sharing the alarm across the crew matters. Someone might have their phone on silent, be asleep, or be off the boat when an alert fires. The more devices in the trip, the more likely someone hears the alarm when it goes off.

The beacon device

One device on the boat is the “beacon” — the device that actually sets the alarm and broadcasts the boat’s location to everyone else on the trip. Choose it deliberately.

Requirements for the beacon

• Cellular capability — the beacon uses cellular to access GPS reliably. A wifi-only tablet won’t work as a beacon.
• Cellular or wifi active — to broadcast the boat’s location out to the other devices on the trip, the beacon needs an active connection. Cellular is more reliable than wifi in most BVI anchorages.
• Kept plugged in and out of the elements — the beacon needs to stay on and stay dry. It’s not a device you’re carrying with you.

Where to physically place the beacon

Place the beacon in the back three-quarters of the vessel, plugged into a reliable power source, and protected from spray. Below deck is fine as long as the device can still hold a GPS signal.

Everyone else’s devices are receivers — they don’t need to be the beacon, and they don’t set the alarm. But if you’re actively monitoring on a receiver, keeping notifications turned on for BoatyAlarm is what makes the shared alerts work.

Setting the alarm

Once you’re tied up and the beacon device is placed:

To stop the alarm, tap the red flashing anchor again.

Only the beacon device can set or adjust the alarm. Devices that joined the trip as receivers can monitor and see alerts, but cannot change the geofence.

The three types of alerts

BoatyAlarm sends three levels of notification:

• Critical warning — boat outside the safe zone. The boat has drifted past the geofence. This is the alarm you need to act on immediately.
• Warning — boat nearing the perimeter. An early heads-up before you’re outside the zone. Not automatically an emergency, but worth checking.
• Low battery notification. The beacon device’s battery is running low. Get it back on power before the alarm goes offline.

What to do when the critical warning fires

Check your location immediately, then assess the vessel. Look at your actual position on the map compared to the mooring — is the boat drifting, or is the alarm registering GPS drift while you’re still tied up? Wake other crew, get eyes on the water, and start engines if there’s any doubt. See Mooring Safety for more on what to do next.

Making sure alerts actually come through

BoatyAlarm relies on your phone’s notification system to reach you. Phone operating systems (both iOS and Android) sometimes limit push notifications from apps that aren’t actively on screen — a well-intentioned battery-saving feature that can get in the way of an alarm you actually want to hear.

A few things that help:

• In your phone’s settings, allow BoatyAlarm to send notifications, including on lock screen and with sound.
• Turn off “low power mode” on the beacon while the alarm is armed (many phones throttle background apps in low power mode).
• If you’re using an iPhone as a receiver, allow notifications from BoatyAlarm to bypass Focus modes.
• Keep the beacon device plugged in — a device with a dying battery gets aggressively throttled by the OS regardless of your settings.

A tool for early detection — not a substitute for judgment

BoatyAlarm is only as good as the GPS signal it’s working with, and it can’t see everything. It’s a tool for early detection — a way to catch a drifting boat before you would notice on your own — not a guarantee against anything going wrong.

The captain remains responsible for the vessel. Use BoatyAlarm alongside other awareness measures: someone keeping watch during high winds, a visual check on the mooring before nightfall, and honest judgment about whether the mooring and conditions are safe. See Mooring Safety for the broader picture.