6 Best Man Overboard Alarms For Solo Sailors That Support Self-Reliance

You’re alone, miles from shore, enjoying a perfect beam reach. You step out of the cockpit to adjust a line, a sudden lurch sends you off balance, and in a heart-stopping second, you’re in the water watching your boat sail away. For a solo sailor, this is the ultimate nightmare scenario. Without a crew to turn the boat around, a simple fall becomes a life-threatening emergency.

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Why Solo Sailors Need Automated MOB Systems

On a crewed boat, a Man Overboard (MOB) event triggers a well-rehearsed drill. Someone points, someone throws a flotation device, and the skipper begins a recovery maneuver. When you’re alone, you are the skipper, the lookout, and the person in the water all at once. If you go over, the boat, under sail or autopilot, will simply continue on its course, leaving you behind with terrifying speed.

This is where automated MOB systems become non-negotiable safety equipment. They are your virtual crewmate, designed to take immediate, life-saving action the moment you’re separated from the vessel. These systems don’t rely on you being conscious or able to reach a radio. They react instantly, either by killing the engine, triggering alarms, or broadcasting your location to rescue assets—including your own boat.

Think of it less as a gadget and more as a fundamental component of your self-reliant setup. A proper MOB system closes the single biggest safety gap in solo sailing. It’s the one piece of gear that can act on your behalf when you are physically unable to, turning a potential tragedy into a recoverable incident.

OLAS Guardian: Wireless Engine Kill Switch

The OLAS Guardian is a beautifully simple and effective solution to the runaway boat problem. It’s a small hub wired into your engine’s kill switch circuit, which wirelessly connects to wearable tags you carry on your person. If a tag goes out of range or is submerged, the Guardian instantly breaks the connection and kills the engine.

Imagine you’re motoring out of an anchorage and get knocked overboard while handling the anchor. Within two seconds of hitting the water, the engine shuts down. The boat stops its forward progress, staying within a few boat lengths of your position. This single action dramatically increases your chances of getting back aboard.

The system also screams a high-pitched alarm through its hub and a connected smartphone app, alerting you to the situation (if you’re still on board and a crew member went over). The app automatically records the GPS location of the incident, providing a clear starting point for a search. It’s a direct, robust system focused on one critical task: stopping the boat.

Fell Marine MOB+: Reliable Wireless Cut-Off

Fell Marine is another key player in the wireless engine cut-off space, and their MOB+ system is known for its rock-solid reliability. Like the OLAS, it consists of a hub (the xHUB) wired to the engine and a wearable fob (the xFOB). If the connection between the two is broken by distance or submersion, the engine is cut.

What sets the MOB+ apart is its focus on a seamless user experience, which is crucial for ensuring you actually use it. The fobs are small, waterproof, and can be worn on a wristband, clipped to a life vest, or carried in a pocket. The system is designed to become an invisible part of your routine—you get on the boat, you click the fob in, and you’re protected.

A critical feature is the one-push override. After the engine is cut, you can restart it after 6 seconds with a single press of the hub button. This is vital, as you need to be able to restart the engine to motor back to the person in the water. Fell Marine built their system around a proprietary protocol for fast and stable connectivity, making it a trusted choice for sailors who prioritize dependability above all else.

Ocean Signal MOB1: AIS & DSC Integration

The Ocean Signal rescueME MOB1 takes a different approach. Instead of stopping the boat, its entire purpose is to ensure you are found. This is a Personal Locator Beacon (PLB) so small it integrates directly into an inflatable life jacket. When the jacket inflates, the MOB1 automatically activates.

Upon activation, it does two things simultaneously. First, it transmits an AIS (Automatic Identification System) MOB alert that pings every AIS-equipped vessel within a roughly 5-mile radius, including your own. Your position appears as an emergency icon on their chartplotters. Second, it sends a DSC (Digital Selective Calling) distress signal directly to your boat’s VHF radio, triggering a loud, unmissable alarm.

This system’s strength is in turning your own vessel into your primary rescue asset. Even if the boat is a quarter-mile away, your chartplotter will show exactly where you are, providing a constant bearing for your return. The tradeoff is that it doesn’t stop the boat. For this reason, many solo sailors use it in tandem with a wireless kill switch for a layered, belt-and-suspenders approach.

Garmin quatix 7: Smartwatch Autopilot Control

Moving into the realm of integrated tech, the Garmin quatix 7 smartwatch offers a unique layer of control. While not a dedicated, automated MOB device in the same vein as a kill switch, it provides powerful capabilities for the self-reliant sailor. When paired with a compatible Garmin marine electronics suite, the watch becomes a remote control for your boat.

Its most compelling feature for a solo sailor is the ability to control the autopilot from your wrist. If you fall overboard but are conscious and able, you could potentially disengage the autopilot or even steer the boat from the water. You can also trigger an MOB event directly from the watch, which instantly drops a waypoint on your chartplotter and begins navigating back to that point.

This is not a passive safety system; it requires your direct input. However, having the ability to interact with your boat’s navigation systems while you’re in the water is a game-changer. It shifts the dynamic from helplessly watching your boat disappear to having a degree of control over its actions, which is the very essence of self-reliance.

Vesper Cortex V1: The Ultimate Safety Hub

The Vesper Cortex V1 is less a single device and more a complete safety and communication hub. It combines a full-function VHF radio, a smartAIS transponder, and a remote boat monitoring system into one integrated package. Its MOB functionality is arguably the most advanced on the market.

The Cortex system works with any AIS MOB beacon, like the Ocean Signal MOB1. When a beacon is activated, the Cortex immediately triggers a loud, spoken alarm on its wireless handsets: "Man overboard! Man overboard!" It simultaneously marks the MOB position on the handset’s screen and on any connected chartplotters.

What makes it truly exceptional is its active rescue guidance. The system provides a continuously updated bearing and distance to the person in the water, and a "track back" mode shows you the path you’ve already covered. It turns the chaos of a recovery into a clear, step-by-step procedure. For the solo sailor with a fully networked boat, the Cortex acts as a vigilant digital first mate, managing the entire MOB incident from alert to recovery.

Sea-Tags Wristband: App-Based MOB Solution

For those seeking a simple and highly accessible solution, the Sea-Tags wristband is an excellent starting point. This system uses a basic but clever concept: a Bluetooth-enabled wristband that communicates with a dedicated app on your smartphone or tablet. It requires no complex wiring or installation.

If the wristband is submerged or moves out of Bluetooth range, the connection is lost. The app on your phone immediately sounds a loud alarm and automatically saves the GPS coordinates of the event. It can even be configured to send a text message with your location to an emergency contact on shore.

The primary tradeoff is its reliance on your phone. The phone must be on, charged, have the app running, and be in a location where it can get a GPS signal. It doesn’t interact with the boat’s systems to kill the engine or trigger a DSC alert. However, as a low-cost, easy-to-use alarm and position-logging tool, it provides a valuable layer of security that is infinitely better than nothing.

Choosing Your MOB Alarm: Key Considerations

There is no single "best" MOB alarm; the right choice depends on your boat, your budget, and your personal safety philosophy. The decision boils down to a few key factors.

First, consider automation and action. Do you want a system that actively stops the boat (a wireless kill switch like OLAS or Fell Marine) or one that alerts you and others to your location (an AIS/DSC beacon like the Ocean Signal MOB1)? Stopping the boat is the most direct solution, while broadcasting your location is critical for being found, especially in rough seas or low visibility.

Second, evaluate integration. Do you have a modern, networked boat with a new chartplotter and VHF? If so, a system like the Vesper Cortex or a Garmin watch can integrate seamlessly. If you have an older boat with simpler systems, a standalone engine kill switch is often a more practical and cost-effective choice.

Finally, think in layers. The most resilient safety systems use redundancy. Many experienced solo sailors pair a wireless engine kill switch with a personal AIS beacon. The kill switch ensures the boat stays close. The AIS beacon ensures you can be precisely located in the water. This combination covers the two most critical aspects of a solo MOB event: proximity and visibility.

Ultimately, choosing an MOB system is an investment in your own survival. For the solo sailor, your boat is your entire world, and being separated from it is the greatest risk you face. The right technology doesn’t replace good seamanship, but it acts as a tireless, vigilant partner, standing watch even when you can’t. It’s the ultimate expression of self-reliance: building a system that can save you when you need it most.