DUBAI — An Iranian gunboat attacked an American-owned tanker with rocket-propelled grenades today, but a nearby U.S. frigate was powerless to take any action.
It could only escort the ship, the 103,584-ton Grand Wisdom, after it was hit because the tanker, fully loaded with oil, flies the Panamanian flag. The U.S. Navy can protect only ships flying the Stars and Stripes.
Eleven Kuwaiti tankers have been re-registered as American in order to gain U.S. naval protection.
Agents for the Grand Wisdom, owned by the Teekay Shipping Co. of Long Beach, Calif., said an Iranian gunboat approached from behind and fired rocket-propelled grenades at the stern.
Fired More Grenades
Then the gunboat, believed based at Abu Musa island about 40 miles from Dubai, raced along the starboard quarter of the ship, firing more grenades into the side.
"The gunboat gave no warning to the Grand Wisdom," a spokesman for the agents said.
He said that no crewmen were injured in the attack on the ship, which was hit by five grenades.
Reporters in a helicopter saw two big holes in the stern and two more in the side of the ship, which was attacked off the nearby port of Jebel Ali.
Anchored Off Dubai
They said the Grand Wisdom was accompanied by the Navy frigate Rentz before the tanker anchored off Dubai. "It's a bit like closing the barn door after the horse has fled," said one shipping agent in Dubai of the Rentz's escort mission.
Shipping sources said the Rentz would have been close enough to help the Grand Wisdom because it carries helicopter gunships equipped with night-vision devices.
The Iranians attacked the tanker about an hour before dawn and would have taken at least an hour to get back to Abu Musa, the sources said.
In Washington, a Defense Department spokeswoman said that the Pentagon's concern was defending ships flying the American flag or vessels under escort by U.S. warships.
First Attack Since Oct. 24
When the Reagan Administration first announced its plan to defend reflagged Kuwaiti tankers, congressional critics said it would lead to American warships defending foreign tankers flying the U.S. flag while American ships flying flags of convenience, like the Grand Wisdom, would be unprotected.
It was Iran's first attack on merchant shipping since Oct. 24, when gunboats attacked another Panamanian tanker, the Prosper Venture L, off Dubai.
But today's raid was not unexpected after regional shipping sources confirmed that Iraqi aircraft hit an Iranian tanker in the northern Persian Gulf.
Iran maintains a policy of hitting a merchant ship in the Persian Gulf every time one of its tankers is attacked by the Iraqi air force.