The size of cruise ships, like the cruise industry itself, is growing. The biggest passenger vessels now carry more than 5,000 people, plus crew.
The world's biggest cruise ship, Symphony of the Seas, has a total capacity of 8,970 people.
So how do you keep track of so many people – particularly in the event of an emergency evacuation when panic, chaos and confusion reign.
The old way would have been to check passengers off against a list – a slow and cumbersome process in an emergency.
Now researchers and cruise companies are working together to test a wireless system – LYNCEUS - that is able to track and account for every passenger.
To quickly find everyone, even in a crisis situation, the crew can use a wireless network that covers the entire ship and shows all the trackers on a computer screen.
Tasos Kounoudes, chief executive of SignalGeneriX, said the system had the potential to save many lives.
“Most people in the sea die not from drowning, but from hypothermia. So it’s very important to locate people in the sea as soon as possible.
“The technologies based on GPS are expensive, so they are not deployed on a mass scale.
“Within the LYNCEUS project, we gave great emphasis to reducing the cost — so this is a cost-effective solution, if we compare it to GPS wearables.
“These devices can be located in all weather conditions, even in extremely rough conditions, and also during darkness. So we can have a precise location of people in the sea under all weather conditions.
“All the technologies have been tested in real time, so we are at a very high technology readiness level. For two years, we are testing them in real environment — on ships, at sea — and we are now ready to proceed with the next step, which is commercialisation.”