Some unnerving bits of info from the Financial Times (italics mine):

According to United Nations estimates, up to 80 per cent of the approximately 6bn metric tons of cargo traded each year is moved by ship. Of that, almost 75 per cent passes at some point through one of the five main choke points in the seafaring economy - the Panama Canal, the Suez Canal, the Straits of Gibraltar, the Straits of Hormuz and the Straits of Malacca.

A terrorist attack against one or more of these transit areas that disabled it for weeks or months - or, in the case of a radiological "dirty bomb" attack, for far longer - could seriously disrupt global trade. The current economic calculus of moving cargo by sea would be rendered useless. Everything from energy prices to insurance rates to shipping freight costs would be affected. The ripple effects, particularly for industrialised nations, are incalculable.

This is what al-Qaeda, with its revamped leadership structure, is counting on. While the US Homeland Security Department argues about how many screening machines to install at airports, terrorists are planning how to convert supertankers carrying liquefied petroleum gas or other chemicals into floating bombs - or perhaps even dirty bombs with help from a rogue nation with nuclear knowhow.

Data compiled by Aegis Defence Services, a UK security consultancy, provide worrying evidence of this. In March, for example, pirates boarded a chemical tanker, the Dewi Madrim near Sabah in the south Pacific for several hours. Their intention was not to ransom the crew or offload its cargo, as south-east Asia's pirates usually do, but simply to learn how to steer it at varying speeds. And in the past few months, 10 tugboats have been reported missing, each of which could be used for close-in manoeuvring of a disabled tanker, hijacked just before entering a big port (at Singapore, say), and just before being set ablaze.

Other dangers to maritime interests are also becoming apparent. In June, for example, a offshore maintenance engineer with deep-sea diving skills, who had been kidnapped in 2000, was released by Abu Sayyaf. He reported that his captors had wanted to learn how to dive, but were not interested in learning how to resurface.

These are exactly the sort of red flags that got missed before 9/11. Let's hope someone is on top of this sort of thing this time. An LPG tanker, properly screwed with to generate a fuel-air explosion, would make one HELL of a big bomb. Think MOAB, only thousands of times bigger.

Oh, and just to make you feel a LOT better, check this out.

It is painfully obvious that we cannot stop terror attacks from a purely defensive mode.