As Captain Tharamadurai noses his patrol boat between the low-slung banks of mangrove forests toward the Malacca Strait, he has centuries-old problems on his mind -- pirates and smugglers.
But for worried governments from Washington to Tokyo, the Malaysian marine police officer represents the frontline of defense against a more modern menace -- terrorists.
The Malacca Strait, a narrow waterway slicing Indonesia's sprawling Sumatra island from mainland Southeast Asia, is one of the busiest shipping lanes in the world, funnelling 50,000 vessels a year between the biggest economies of the West and the East.
A hunting ground for pirates from ancient times until today, it carries a third of global trade and more than 10 billion barrels per day of oil to Japan, South Korea, China and other Pacific Rim countries.
The US Energy Information Administration describes it as the "key choke point in Asia."
From the teak foredeck of his 33.5m PX-27, Tharamadurai watches the stately procession of oil supertankers, liquid-petroleum-gas carriers and hulking container ships navigating the link from the Indian Ocean to the South China Sea and the Pacific.
And he knows that Osama bin Laden's al-Qaeda terrorist network has been watching him.
Videos showing Malaysian boats on patrol in the strait were found in an al-Qaeda hideout in Afghanistan when the US invaded after the Sept. 11, 2001, attacks on New York and Washington.
The discovery sparked concern that the success in using hijacked airliners as weapons could inspire a similarly dramatic attack using an oil supertanker as a monstrous bomb, perhaps against the strategic port of Singapore, or a vessel such as an American warship.
The authorities in Singapore say they uncovered a plot to attack US military ships in the strait, along with other targets in the island state, when they arrested members of the al-Qaeda-linked Jemaah Islamiyah (JI) terrorist group late in 2001.
JI is accused of responsibility for the Bali bombing in neighboring Indonesia in October last year which killed more than 200 people, mostly Western tourists, in the world's biggest terror attack since Sept. 11.
"We always have this thing in the back of our mind," admits Tharamadurai, as the pea-green waters of the strait darken under the thunderclouds of a building tropical storm.
After the discovery of the al-Qaeda tapes, patrols were doubled. During the Iraq war particular attention was paid to Western oil installations and to the Malaysian-owned Star Cruises passenger liners heading out to sea.
"But things have been good on the strait," says Tharamadurai, a burly, cheerful 15-year veteran of Malaysia's marine police who holds the rank of assistant superintendent.
In an attempt to keep things that way, both the US and Japan have reportedly offered assistance in patrolling the 800km waterway, which narrows to just 2.5km wide off Singapore.
Marine Police Commander Muhamad Muda, however, said that while the exchange of intelligence and experience were always welcome, "we don't need foreign ships to come into Malaysian waters for joint patrols. I don't think our government would like that kind of thing."
Japan's interest is fundamental -- 90 percent of its oil is shipped through the strait.
"Japan has come to my office several times talking about the issue," Muda says.