The hijacking highlighted the vulnerability of even very large ships and pointed to widening ambitions and capabilities among ransom-hungry pirates who have carried out a surge of attacks this year off Somalia.
Saturday's hijacking of the MV Sirius Star tanker occurred in the Indian Ocean far south of the zone patrolled by international warships in the busy Gulf of Aden shipping channel, which leads to and from the Suez Canal. A U.S. Navy spokesman said the bandits were taking it to a Somali port that has become a haven for seized ships and bandits trying to force ransoms for them.
Maritime security experts said they have tracked a troubling spread in pirate activity southward into a vast area of ocean that would be extremely difficult and costly to patrol, and this hijacking fits that pattern.
"It is very alarming," said Cyrus Mody, manager of the International Maritime Bureau. "It had been slightly more easy to get it under control in the Gulf of Aden because it is a comparatively smaller area of water which has to be patrolled, but this is huge."
The tanker, owned by Saudi oil company Aramco, is one of the largest ships to sail the seas. It is 330 1,080 feet long, or about the length of an aircraft carrier, and can carry about 2 million barrels of oil.
Fully loaded, the ship's cargo could be worth about $100 million. But the pirates would have to way of selling crude and no way to refine it in Somalia.
Lt. Nathan Christensen, a spokesman for the U.S. Navy's 5th Fleet, said the Sirius Star was carrying crude at the time of the hijacking, but he did know how much. He also had no details about where the ship was sailing from and where it was headed at the time of the attack.
Christensen said the bandits were taking the ship to an anchorage off Eyl, a northeastern Somali port town that is a haven for pirates and the ships they have seized.
The ship was sailing under a Liberian flag and its 25-member crew includes citizens of Croatia, Britain, the Philippines, Poland and Saudi Arabia. A British Foreign Office spokesman said there were at least two British nationals aboard the vessel.
The Sirius Star was attacked more than 450 nautical miles southeast of Mombasa, Kenya, the U.S. 5th Fleet said in a statement from its Middle East headquarters in Bahrain.
"It's the largest ship we've seen hijacked and one attacked farthest out on the sea," Christensen said.
The capturing of the oil tanker represents a "fundamental shift in the ability of pirates to be able to attack merchant vessels," he said.
Classed as a Very Large Crude Carrier, the Sirius Star was commissioned in March and is 318,000 dead weight tons.
With a full load, the ship's deck would be lower to the water, making it easier for pirates to climb aboard with grappling equipment and ladders, as they do in most hijackings.
It is not clear if there was a security team on the vessel. An operator with Aramco said no one was available to comment after business hours. Calls went unanswered at Vela international, the Dubai-based marine company that operated the ship for Aramco.
Somali pirates are trained fighters, often dressed in military fatigues, using speedboats equipped with satellite phones and GPS equipment. They are typically armed with automatic weapons, anti-tank rocket launchers and various types of grenades.
As pirates have become better armed and equipped, they have sailed farther out to sea in search of bigger targets, including oil tankers, among the 20,000 tankers, freighters and merchant vessels transiting the Gulf of Aden each year. Attacks have increased more than 75 percent this year.
With most attacks ending with million-dollar payouts, piracy is considered the most lucrative work in Somalia. Pirates rarely hurt their hostages, instead holding out for a huge payday.
The strategy is effective: A report last month by a London-based think tank said pirates have raked in up to $30 million in ransoms this year alone.
In Somalia, pirates are better-funded, better-organized and better-armed than one might imagine in a country that has been in tatters for nearly two decades.
They do occasionally get nabbed, however. Earlier this year, French commandos used night vision goggles and helicopters in operations that killed or captured several pirates, who are now standing trial in Paris. The stepped-up international presence recently also appears to have deterred several attacks.
Raja Kiwan, a Dubai-based analyst with PFC Energy, said the hijacking raises "some serious questions" about securing such ships on the open seas.
"It's not easy to take over a ship" as massive as an oil tanker, particularly VLCC's that can transport about 2 million barrels of crude, he said. He said such vessels typically have armed guards but could not say if that was the case with the Sirius Star.
Pirates have gone after oil tankers before, most recently in October when they were thwarted by a Spanish military plane.
Warships from the more than a dozen nations as well as NATO forces have focused their anti-piracy patrols in the Gulf of Aden, increasing their military presence in recent months.
But Saturday's hijacking occurred much farther south.
Graeme Gibbon Brooks, managing director of British company Dryad Maritime Intelligence Service Ltd, said the increased international presence is simply not enough.
"The coalition has suppressed a number of attacks ... but there will never be enough warships," he said, describing an area that covers 2.5 million square miles.
He said the coalition warships will have to be "one step ahead of the pirates. The difficulty here is that the ship was beyond the area where the coalition were currently acting."
