On the centenary of the Titanic disaster of 1912 another huge cruse ship sank. The Costa Concordia ran aground in January 2012 hitting a rock in the Tyrrhenian Sea. Although most of the passengers and crew were evacuated safely over a 6 hour period, 32 people died. There is a catataxic side to this tragedy. As cruse liners have ballooned in size, the safety systems have not scaled up appropriately. In this case, more of the same is not just different but also deadly.

Big cruise ships are top heavy
Cruise ships have been a boom industry and as a result the ships have got bigger and bigger in order to achieve economies of scale. Today’s ships are twice the size of a decade ago and can carry 6,000 passengers and 1,800 crew. That’s the size of a small town and four times bigger than the Titanic. Since most passengers want a nice view from their cabin, there are more and more decks stacked above the waterline. At the same time, the ships need to be able to get into traditional old ports (where tourists like to go) rather than to anchor offshore and be ferried in on small boats. That means they need a shallow draught. Both factors mean that ships are becoming increasingly top heavy: there is a lot more above the waterline and too little underneath.

Lifeboats and logistics
A second factor is the lifeboat problem. This technology has not really changed since the time of the Titanic. When the top heavy Costa Concordia heeled over, that put half the life boats out of action because they could no longer be lowered into the water. Every passenger is (in theory) allocated a berth in a lifeboat matching their cabin allocation. It is a logistical nightmare to try and shepherd 7,800 people to their allocated lifeboat seat. Just picture this. A typical movie theatre has say 250 seats. Now imagine 30 cinemas stacked on top of each other in a sky scraper with every seat full. You randomly distribute tickets with seat numbers in a different cinema to all the members of all the audiences. Then you blow a whistle and tell them to find their new seats in the new auditoriums. Result: utter chaos. Now imagine doing it in the dark, at sea with the rooms gradually tilting over to one side…..
This lifeboat issue is such a logistical problem that the International Maritime Organisation advises Captains to try and use the ship itself as a “big lifeboat” and return as fast as possible to port for evacuation. In other words, the best advice available about lifeboats is to try to avoid using them at all.
Both the ship design and the lifeboat problem are problems of scale. Andrew Linington of Nautilus International, a maritime union, says “The alarm bells have been ringing with many of us for well over a decade now. These ships are floating hotels – skyscrapers, really. The design has been extrapolated from that of smaller ships. We believe a lot of basic safety principles are being compromised to maximise the revenue”

Surface area to volume problem
A big ship is different from a scaled up small ship which is the essence of catataxis. If you just inflate the ship design like a balloon it becomes top heavy. This is a version of the surface area to volume problem.  The outside surface of the ship – which passengers have to get to in order to escape  – increases with the square but the internal volume increases with the cube. So logistical problems with ever larger cruise ships grow exponentially. More of the same is different.