Top three theories on what damaged Japanese oil tanker near Iran

Numerous theories have surfaced for what damaged the Japanese oil tanker sailing between Oman and Iran on Thursday. Investigators say it may have been a sea mine, a pirate attack, or a collision with a submarine.

The M Star Japanese oil tanker is seen at sea near Fujairah port in the United Arab Emirates July 29.

Mosab Omar/Reuters

July 30, 2010

Whatever it was that shook a 260,000-ton Japanese supertanker as it sailed through calm waters between Oman and Iran just after midnight Wednesday, it was not a freak wave.

But beyond that, officials investigating a huge dent in the side of the M. Star are still some way off establishing exactly what happened.

Several theories are doing the rounds: The 333-meter-long ship collided with a submarine or a degraded sea mine left over from the Iran-Iraq war; there was an internal explosion; or, most unsettling of all, it was the target of an attack by pirates or terrorists in a strategically vital stretch of water in a sensitive region.

But Mitsui OSK Lines, operator of the world’s second-biggest fleet of oil tankers, was standing by its initial suspicion that the M Star had been “attacked by external sources” as it left the Gulf and entered the Strait of Hormuz, a narrow waterway through which 40 percent of the world’s seaborne oil passes. Japan depends on the Middle East for 90 percent of its oil.

All that the investigation team – which has grown to include the US Navy, maritime authorities from Britain and Japan, a Dubai-based expert on military attacks, and ship operator Mitsui – knows for sure that the cause remains a mystery.

Initially, local reports said the Japan-bound M. Star, laden with 2.3 million barrels of crude oil, had been struck by a freak wave triggered by an earthquake in Iran.

Sea mine or submarine seen as increasingly likely

By Thursday, speculation was growing that the ship had collided with a submarine or a sea mine.

“What we know is that some collision happened,” Capt. Mousa Mourad, a general manager at the United Arab Emirates port of Fujairah, where the M. Star is now moored, told a news conference. “We don’t know what it was. It is possible that it could be a submarine collision, or that it could be a sea mine.”

The collision theory has not dispelled fears that the tanker had been targeted by pirates or terrorists. The scene of the incident lies a few hundred kilometers north of where Somali pirates have hijacked supertankers, including, in April, a South Korean ship bound for the US. The strait has also been identified as a potential target by Al-Qaeda.

Mitsui officials showed pictures of a large square dent on the rear starboard side of the ship’s hull. The explosion – or collision – had also damaged railings, shattered windows, and broken furniture and fittings. News agency photos of the vessels showed that a lifeboat had been blown away on impact.

Crew aboard the M. Star reported seeing a flash, followed by an explosion. One sailor sustained light injuries, but there was no oil leak and the strait remained open for business.

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