In the BBC’s report of the ongoing Korean ferry sinking, this line stood out (in the analysis, off to the side):
The speed with which it flipped over and sank is a major concern.
This is a well-known problem with car ferries. In order to make them economical you need to have fairly open car decks without any watertight bulkheads dividing the decks into compartments as you would on any other type of vessel. You want all your cars to be able to drive unhindered into what is effectively a large floating car park and then drive off the other end when the ferry reaches its destination. The problem with this is that water sloshing about on an open deck makes a vessel extremely unstable.
Back in the late ’90s I found myself stuck at home in Pembroke with a computer but no internet (it wasn’t widespread in homes back then) and an assignment to write for my engineering degree on engineering risks. I had very little material to base an essay on, but there was a stack of old New Scientist magazines of my sister’s lying about, and one of them (dated August 1990) had this article in (subscription required), which is introduced as follows:
The risks of ferry travel: Many car ferries are built with a fatal design flaw. If the vehicle decks flood, the ferries are likely to capsize rapidly.
The article said that an inch of water covering a car deck was enough to cause a ferry to capsize, due to the enormous momentum of the sloshing action. An inch isn’t much when you have the sea pouring in.
This is why ferries tend to sink so quickly, with both the Herald of Free Enterprise (March 1987) and Estonia (September 1994) disasters being the two that I remember happening; the first because it involved a lot of Brits in what seemed to be a spate of home-grown disasters (the Kings Cross Fire in November 1987, Piper Alpha in July 1988, and the Marchioness in August 1989) and the second because of the harrowing accounts of the ship listing severely before disappearing into the freezing Baltic Sea. I’ve since been on a ferry from Finland to Tallinn, and ending up in the water doesn’t bear thinking about.
The New Scientist article has stuck in my mind since, probably because I had to write an essay on it in the absence of any other source material. I got a good mark by the way, mainly because I actually wrote a good essay, but the lecturer did remark that my basis was somewhat limited! The other aspect of ferries mentioned in the article which contributed to their poor safety record – on some measures, ferry travel is the most dangerous in the world – was that the operators tend to get complacent. You can imagine, doing the same, normally short, route day after day would breed complacency among the crew in terms of safety equipment inspections, evacuation drills, etc. Also, a lot of ferries, especially in the developing world, are operating on a shoestring budget whose owners aren’t much interested in spending money on things like maintenance and inspections. Add in poor training and experience of crew and you have, well, a recipe for disaster.
For all of these reasons, underpinned by the fatal design flaw described in New Scientist, I fear ferry disasters – like air crashes – will always be with us.