Modern ships dwarf even the greatest vessels of earlier eras. Some supertankers weigh over 500,000 tons and are the biggest moving objects ever built. Their decks are as long as several football pitches - crews get about them on bicycles - and their propellers are as wide as a house. They are the cheapest way of moving around the world such heavy cargoes as oil, metal ores, coal and grain.
Modern ships are equipped with radar, radios and satellite navigation systems. But even this equipment fails to prevent the thousands of accidents on the high seas that occur every year, most of them involving human error.
Distress signal
The rules governing the 'Safety of Life at Sea' are drawn up by the International Maritime Organisation (IMO) and are observed by 150 countries around the world. For example, all ships must now carry a Global Maritime Distress and Safety System. This electronic system uses signals from satellites and radio masts on land to pinpoint a ship's position anywhere in the world. If disaster overwhelms a ship too quickly, and there is no time to send a distress signal, the Global Maritime Distress and Safety System sends one automatically.
Double bottoms
Nevertheless, in recent years the IMO has attracted considerable criticism. It has been accused of failing to draw up timely safety regulations for oil-carrying ships, not least of which was the failure to insist that tankers be built with reinforced hulls. The IMO regulation that made the fitting of double bottoms to oil tankers mandatory only took effect in 1995, six years after the Exxon Valdez disaster, and was limited to new tankers.
