The USS Newport News fast-attack submarine collided Monday night with the Japanese oil tanker Mogamigawa near the Strait of Hormuz, which separates Iran from the United Arab Emirates.
Both vessels suffered minor damage but no injuries, fuel spills or radiation were reported.
"The crew of the Newport News most probably fell victim to poor sonar conditions in the area," Gennady Illarionov, a former submariner, said in an exclusive interview with RIA Novosti.
"The sonar operator apparently did not hear the noise produced by the Japanese tanker, because it is fairly quiet," the expert said. "It [the tanker] has a propulsion plant located at the stern, and the collision occurred in the middle of the hull, about 200 meters (650 feet) from the rear of the ship."
"Such occurrences are rather frequent, because at a depth of 40 meters (130 feet) in poor weather there are strong wind waves that interfere with the acoustic field and could prevent a sonar operator from hearing the noise of a nearby target," Illarionov said.
He said the captain of the U.S. submarine was most likely to blame for the collision, because it occurred while the submarine was surfacing and the Japanese vessel was simply maintaining its course in the narrow strait.
"Surfacing is one of the most complicated maneuvers for submariners, especially from a depth of 40 meters to the surface," Illarionov said. "It is the most dangerous stretch, and that is when the two vessels collided."
The expert also said that 40 meters is a fixed depth in preparation for surfacing. At that depth, a collision is impossible and it allows a sonar operator to scan the acoustic horizon before reporting to the captain, who subsequently makes a decision to surface.
Following the captain's orders, the crew raises the vessel to periscope depth, and the captain is supposed to visually scan the horizon and make sure it is clear before finally surfacing.
Illarionov said the captain should have received the sonar operator's report before making the decision to surface. Otherwise, it would have been a violation of strict procedures.
In addition, the expert said, the Newport News, a Los Angeles class nuclear submarine, is vulnerable to sea collisions because of the design of its hull.
"These submarines have a single-hull structure," Illarionov said. "And any collision with another vessel can lead to serious consequences for them [the submarines]."
"I think the Americans were simply lucky because it was apparently not a direct hit," he said, adding that despite the 50-millimeter thickness of the hull, the impact should have left a deep dent in the super-hard steel.
The USS Newport News (SSN 750) has been operating as part of a U.S. Navy carrier strike group patrolling the Persian Gulf and nearby seas. It has a crew of 127.
Another Russian naval expert said Tuesday it was the captain of the submarine who was responsible for the collision.
"The incident involving the American submarine and the Japanese tanker in the Arabian Sea was due to intensive shipping in the region, which demands a high level of caution from captains of vessels, in particular from captains of nuclear submarines," the expert said.
"Most likely, the captain of the American vessel inadequately assessed the underwater and surface situation while the submarine was surfacing," he said.
The collision is not the first between a U.S. submarine and a Japanese vessel. In February 2001, a U.S. nuclear submarine, the Greenville, ran into and sank a Japanese fishing vessel near Hawaii, killing all nine people on board the Japanese boat.