Sensors that save lives: CCTVs on cruise ships

Cruise companies have long used CCTV to check for passengers who fall overboard, a method critics dismiss as being dangerously unreliable. But sophisticated new sensors, which automatically report incidents to the bridge, might be about to change things. Andrea Valentino talks to Reidulf Maalen, a retired captain for Royal Viking and Crystal Cruises, and Captain Abdelkhalik Selmy, a lecturer at the Arab Academy for Science, Technology and Maritime Transport, about the latest developments.

You’re falling overboard a ship at sea. As you slip over the barrier, the first thing you would feel is the gush of air against your limbs and hair. The biggest cruise ships are ten storeys high: it would take a few seconds to reach the water. Assuming you weigh about 80kg and fall 40m, you would hit the waves at 100km/h. That’s as fast as a sports car on an empty motorway.

If you survive the drop, gasping and frantic, with the taste of salt in your mouth, you could start paddling, but not for long. Most people can only manage two hours before their legs go numb and they start to go under. If the water is cold, you have even less time. Fall into the Baltic Sea, or the North Atlantic in winter, and you would be unconscious in half an hour.

All the while, your ship is gliding away. It’s evening, and the lights shimmer through a murky sky. Did someone see you go in? Even if they did, you already feel tired. You look around. You are alone. Everything is quiet, except for the slap of the water against your ears, and a few seagulls.

Most cruise passengers only ever need to imagine this nightmare. Fortunately, the overall number of man-overboard (MOB) incidents is low, with one accident for every 2.7 million cruise passengers. But the chances of survival once you fall in are remote, with 78% of cases resulting in death, according to statistics compiled by CruisePage.com.

In the past, cruise companies relied on CCTV cameras to catch MOB episodes, but critics claim that these systems are too slow to help victims in the moment, or miss accidents altogether. However, new technology will enter the market soon, giving operators the chance to finally detect MOB incidents as they happen, in order to save passengers before the water snatches them.

A life and death situation

Working as a cruise captain at Royal Viking and Crystal Cruises for more than 30 years has given Reidulf Maalen plenty of experience with MOB incidents. “You’re faced with a life and death situation,” he says. “You have to decide what to do. Are you going to turn around and do a search pattern? It’s a very difficult decision for a captain.”

Whatever a captain chooses, they need to act quickly. If you sit in water colder than 4ºC for longer than an hour, hypothermia is inevitable. Many people drown before that, due to rough seas or because of injuries sustained by falling. Even if they are seen going overboard, passengers are still no safer.

“High waves, poor visibility and propeller wake all make it difficult to detect passengers,” says Captain Abdelkhalik Selmy, a lecturer at the Arab Academy for Science, Technology and Maritime Transport in Alexandria, Egypt. Ship speeds also matter. Modern cruise ships can now steam along at 25kt (46km/h). Unlike cars, which can travel at that speed and stop in about 30m, cruise ships have an enormous bulk that means they need a full mile before they can turn round.

It hardly helps that cruise passengers are less aware of the dangers of life at sea than professional sailors, Selmy continues. “In general, cruise passengers are less experienced than [those] on freight ships. They are not wearing a lifejacket, and might have taken alcohol or drugs.” Maalen agrees, saying that a “party atmosphere” can contribute to accidents.

Alcohol definitively caused 6% of cruise MOB incidents between 2000 and 2015, according to Cruise Junkie, a statistics website that uses news stories to collate cruise liner MOB accidents. However, the statistics remain ominously inconclusive. Cruise Junkie has found that many eyewitnesses report seeing MOB victims drinking before they fall overboard or disappear. Unless a passenger is found alive, it is impossible to know exactly what happened.

CCTV setbacks

Maalen and Selmy agree that the industry’s use of CCTV has major flaws. For one thing, cameras are unhelpful for detecting passengers in poor weather, Maalen says, adding, “CCTV cameras are fine in perfect conditions. But if you want an MOB system that works, you need to have something that works in all conditions: fog, rain, snow, sleet, darkness and sunshine.”

Another problem is that CCTV relies on crew members spotting MOB emergencies, which is something they often miss. “If you have somebody sit and stare at these cameras 24/7, then there’s a chance you’ll see something,” Maalen continues. “But [it is difficult], unless you have something that triggers the alarm when somebody goes overboard.” Indeed, most CCTV systems are not linked to the central electronic chart display and information system on the bridge, meaning crew members cannot track the exact spot where someone fell overboard.

To be fair, cruise companies have made attempts to improve ship safety. CLIA now expects its members to include ‘minimum railing heights and structural barriers’ on their ships. Selmy accepts that all of this helps, as do International Maritime Organisation rules on risk assessments, and search-and-rescue manoeuvres. But he maintains that cruise companies can do more. “Over the past 20 years, there have been about 20 MOB incidents annually,” Selmy stresses. “This is not a small number; each of these is a human life.”

For his part, Selmy suggests replacing CCTV systems with a more sophisticated arrangement. Rather than relying on CCTV alone, cruise companies could use a combination of infrared sensors and alarms to find MOB victims quickly. “There must be minimum technical requirements to [implement] systems like this,” he says.

There has been a surprising lack of progress in this areas and much of the confusion stems from the Cruise Vessel and Security Safety Act (CVSSA), signed into law by former US President Barack Obama in 2010. According to the act, cruise companies are obliged to “integrate technology that can be used for capturing images of passengers or detecting passengers who have fallen overboard, to the extent that such technology is available”.

Operators have long argued that sensor technology is simply not reliable enough to be ‘available’ – and they have a point. Rough seas can easily batter unprotected sensors, while false alarms “put captains in a difficult position”, explains Maalen. After all, too many false alarms and crews risk dismissing a genuine MOB incident.

Nonetheless, Selmy remains cynical about shipowners’ motivations. “It’s about economics,” he says simply. “Complete detection systems are too expensive.” Maalen partly agrees, saying that the ambiguous wording of the CVSSA lets cruise companies “hide behind” the law. On the other hand, he is aware that there are genuine difficulties in developing a reliable alternative to CCTV. “When people hear about an MOB situation, they wonder why there isn’t a system available with the latest technology to detect it,” he says. “But it’s not as easy as it sounds.”

Saving systems

It was these challenges that led Maalen, together with a team from the Chalmers University of Technology in Gothenburg, Sweden, to work out a solution. The result is the Multisensor Offshore Safety System (SOS). Unlike older CCTV-based approaches, SOS uses carefully placed sensors to keep passengers safe.

“Each of the sensors are able to capture specifics for the MOB situation, whether it’s in sunshine or rain,” Maalen says. “That’s why we’ve ended up with several sensors that we’ve fused into one system. We also use a multilayer deployment, so we have full coverage of the ship.” All of this is linked to a computer system on the bridge that immediately informs the crew of a problem.

At the same time, SOS is specifically designed to recognise objects within 100m of the hull, making it perfect for MOB incidents. Its long-distance sensors extend up to 2,000m to the aft of a ship. This allows crew members to pinpoint a passenger’s location, even if conditions are poor or the vessel is sailing away. Wherever the sensors are on a ship, protective covers shield them from waves and wind.

Maalen has also worked hard to stop false alarms. “Each sensor will be able to verify whether an alarm [was triggered by] an object or person,” he says. “We have run tests for several years with all sorts of objects going overboard, including dummies heated up to regular body heat temperatures, in all conditions. We’ve based our system on the positive verification of the object going overboard.”

Wider adoption

With a prototype ready to go, Maalen is now working towards getting SOS approved. “We have been certified by DNV GL, which is one of the biggest verification companies in the world, if not the biggest,” he says.

This is an important step, as Maalen expects that this technology will transform how operators deal with MOB incidents. “As soon as there is a system that satisfies the authorities, I am pretty confident that it’ll be approved,” he says. “It will become a requirement on all cruise ships over a certain size.”

There are signs that cruise companies are moving in this direction already. Last year, MSC announced that the MSC Meraviglia would get its own sophisticated video surveillance system. It has many of the same features as SOS, including robust technology to combat false alarms.

As other companies adopt similar systems, Selmy expects that the technology will become cheaper, making it even easier to adopt. He ultimately imagines a world where cruise ships are equipped with several different ways to monitor MOB accidents, and save passengers if they go overboard. “Drones equipped with a lifebuoy and camera could be deployed to the place where the passenger fell overboard,” Selmy suggests. “The drone could release the lifebuoy over them in an accurate position.”

It’s about time that the industry took note and pushed for change, so no one has to endure the terrible consequences of falling overboard.