When someone goes overboard, every second between the fall and the alert matters. In marine safety survival, the right man overboard beacon can mean the difference between a quick recovery and a long search. Two options sit at very different price points: the ONWA KS-33R AIS MOB Positioning Beacon Tracker at $177.65 and the sMRT Alert MOB at $333.33. Both are new, but they approach the problem differently. This head-to-head will help you decide which one fits your boat, your crew, and your budget.
Quick Verdict
Choose the ONWA KS-33R if you want AIS-based GPS target tracking that feeds into your plotter or onboard navigation system. It costs significantly less and still runs for at least 24 hours. Choose the sMRT Alert MOB if you prefer a dedicated SOS man-overboard alarm that's easy to carry and made for a range of vessels from boats to yachts and RIBs.
Comparison
| Product | Price | Key Highlights |
|---|---|---|
| ONWA KS-33R AIS MOB | $177.65 | AIS MOB positioning beacon, GPS tracking, LED flashing, buzzer, 24-hour operation, serialized ID |
| sMRT Alert MOB | $333.33 | Man overboard beacon, SOS alarm, emergency device, UK origin, part number MOA-50070 |
Where Each Product Wins
The ONWA KS-33R wins on price and on AIS integration. It transmits GPS target tracking information over AIS, and when paired with a compatible plotter or navigation system, it helps the crew locate the person in the water fast. The sMRT Alert MOB wins on being a straightforward SOS alarm. It's compact, reliable, and designed for sailors, boaters, and watersports enthusiasts, and it's built for real-world marine conditions.
Product Notes
ONWA KS-33R AIS MOB Positioning Beacon Tracker
The ONWA KS-33R is a small, lightweight personal beacon that mounts on a life jacket. Its standout feature is AIS transmission: it sends GPS target tracking information over AIS, so any compatible plotter or onboard navigation system can show exactly where the beacon is. You also get an LED flashing indicator and a buzzer, plus a unique serialized ID. The listed runtime is at least 24 hours of continuous operation, which gives you a solid window for recovery. At $177.65, it's the more affordable option here. The trade-off is that the ONWA is built around AIS tracking rather than a standalone SOS alert. If your priority is to raise a loud, immediate alarm that someone is overboard, the sMRT is the one that spells out SOS and emergency.
sMRT Alert MOB | Marine Safety | Man Overboard Beacon | SOS | Emergency
The sMRT Alert MOB is a purpose-built man overboard alarm. It comes from Wescom in the United Kingdom and carries part number MOA-50070. It's built around a simple SOS alert: press the emergency button to instantly warn nearby crew. It's lightweight and easy to carry, and it suits a range of vessels, including boats, yachts, RIBs, and sailing vessels. At $333.33, it costs more than the ONWA, but you're getting a dedicated SOS device that doesn't rely on a plotter to get the message across. The ONWA, by contrast, includes AIS tracking for those who want the beacon to appear on a navigation screen. If showing up on your navigation screen is a must, the ONWA is the one to choose.
Final Choice by Use Case
If you already use a plotter or chartplotter and want a man overboard beacon that appears as a GPS target on your screen, the ONWA KS-33R is the practical pick. It gives you tracking data, a buzzer, and LED feedback for less money. If you want a simple, dedicated SOS alarm that you can clip on without worrying about integration, and you're comfortable spending more, the sMRT Alert MOB delivers that peace of mind.
