Cruise ship ‘overboard’ alarms explained as Netflix fans dissect Amy Bradley theory shrugged off by family

Since Amy Bradley vanished from a Royal Caribbean cruise 27 years ago, ships have seemingly upped their safety precautions - although perhaps not quite as drastically as you'd expect.

At 23 years old, Amy Bradley disappeared near Curaçao on March 24 1998. She was vacationing on Royal Caribbean's Rhapsody of the Seas with her mom, Iva, dad, Ron and brother Brad.

Amy Bradley is Missing, a three-part Netflix series, explores the theories surrounding her disappearance.

Amy's dad Ron claims he last saw his daughter's legs as she lay on the deck chair of their cabin's balcony at around 5.30am.

He says he was woken by a sound at around 6am and when he looked out the window, his daughter was nowhere to be seen.

The mysterious circumstances of her disappearance - and lack of concrete answers - have sparked all kinds of theories.

Amy Bradley, who vanished from a cruise ship in 1998, and her brother Brad (Netflix)

Multiple alleged sightings of Amy were reported in the years since, leading people to believe she could've been sex trafficked off the boat.

But Amy - who would be 51 years old today - was never tracked down.

Another theory discussed in the documentary - but dismissed by her family - is that she either fell or jumped overboard.

FBI agents found the Bradley's balcony table pushed up against the ship's rails, alongside a pair of her sandals.

Could Amy have perched on the table to throw up, and have accidentally fallen off? Could she have moved it there to purposefully jump off?

Or were the table and shoes moved by cleaning staff after she'd vanished? These are the questions her family will never know the answers to.

However, in the series, Curaçao boating experts claim if Amy had fallen overboard, strong currents would've pushed her body to shore. It never did.

Her family don't agree with the theory and still hold strong faith that their daughter is alive today.

The series has been a major talking point; despite releasing on July 16, people are still mulling over the details of the case now.

Taking to Reddit, one social media user reckoned Amy fell overboard, claiming the most likely scenario 'is that she just fell'.

"I am really skeptical when witnesses state they saw her, a lot of people look alike," they continued in part. "It’s a shame, her family cannot get confirmation and have to live with questions."

A second weighed in: "Me too. I think she went overboard whether intentionally or unintentionally."

A third added: "I mean this was always most likely. I wish cruise ships had railing alarms or something."

In 2025, automatic 'man overboard' alarms are a thing - yet not all ships have them.

How do man overboard alarms work?

A MOBtronic cruise ship alarm (MARSS)

Four to 12 MARSS’s MOBtronic alarms are mounted across the vessel's rails and deckings, depending on the ship's size.

Each pod contains Doppler-enabled micro-radar that continuously scans a zone approximately 262 feet long, 26 feet wide, and at least 18 feet high.

This acts as a 'tripwire' to detect unexpected movements near the edge.

Upon detecting motion via radar, the thermal camera activates. It checks for body heat and shape to determine if the object in view is indeed a person.

The system’s onboard processor uses AI algorithms and machine learning, NiDAR CORE, to analyze the data. It confirms variables like fall direction, speed, size, shape, and performs layered decision-making before raising an alarm.

Once confirmed, the system instantly alerts the bridge, shares video clips, and integrates with navigation systems to provide the person’s last known position, including estimated drift and direction.

Its website says it achieves over 95 percent detection probability and averages fewer than one false alarm per day.

Which ships have man overboard alarms?

All Disney cruises are reportedly fitted with automatic 'man overboard' alarms (Horacio Villalobos Corbis/Corbis via Getty Images)

Only a small number of cruise liners are fitted with these automatic alarms.

Among them is Disney Cruise Line, which has its entire fleet kitted out with some form of man overboard detection, USA Today reports.

Back in June, a five-year-old passenger fell overboard on a ship traveling from the Bahamas to Fort Lauderdale, Florida and her dad jumped in after her. Both were rescued.

Other cruise liners reported to have overboard alarms include MSC Cruises, as well as Ambassador Cruise Line which has fitted its cruise ship Ambition with a new AI system called ZOE, as per the International Fire and Safety Journal.

Meanwhile, MARSS MOBtronic is on 'quite a few' ships already, according to its CEO - but cruise lines usually don’t name themselves publicly.

Why do so little ships have man overboard alarms?

The 2010 Cruise Vessel Security and Safety Act states ships in US waters must use technology to spot or record passengers going overboard - but only if reliable systems existed. At the time, they didn’t: early cameras and sensors triggered constant false alarms, so regulators didn’t enforce it.

Over the 2010s, companies developed better man-overboard detection tech, and the industry worked with the International Organization for Standardization to set global standards.

So while ISO certification is helping boost adoption, it's still not necessarily enforced.

What are the chances of falling off a cruise ship?

Falling off a cruise is extremely rare, with Cruise Lines International Association (CLIA) putting the odds at about 0.00004 percent.

Between 2009 and 2019, the CLIA reported 212 man overboard cases, averaging 19 per year.

Of those, 48 incidents were successfully rescued, the report states.

These figures might sound alarming at first, but when you consider the sheer number of passengers aboard the 300-plus cruise ships operating globally, the odds remain incredibly low.