An accident involving a United States warship and an oil tanker, which occurred in Singapore waters last August and left 10 people dead, was brought on by a “sudden turn” made by the warship.

Less than three minutes later, the American guided-missile destroyer USS John S. McCain collided with oil tanker Alnic MC as they were transiting through the Singapore Strait.

The warship was in the path of the oil tanker, said the Transport Safety Investigation Bureau (TSIB) – a unit under the Transport Ministry – which released its investigation report on Thursday (March 8).

Ten American sailors on board the McCain died in the accident, which occurred at about 5.24am near Pedra Branca – situated at the eastern entrance to the Singapore Strait.

In a 35-page report made public yesterday which gave a blow-by-blow account of what happened, TSIB said that the action by the US warship resulted from a series of missteps that took place after a transfer of propulsion controls.

Instead of one crew member managing both speed and steering, the US commanding officer had ordered another member to take over managing speed minutes before the accident.

Inadvertently, along with speed, the steering operations on the US warship also got transferred to the second crew member. The sailor who was originally in charge of steering reported a loss of steering. Alternative steering kicked in, while speed was reduced But because the throttles on each side of the ship were not coupled, the left side ended up slowing down more than the right, and the US warship veered left, in the path of the Alnic.

In its report, TSIB said that the crew of the US warship did not recognise the processes involved in the transfer of propulsion and steering control. They were “likely to have lacked the requisite knowledge of the steering control system due to inadequacies in training and familiarisation”, the report added.

Before the vessels collided, the captain of the Alnic had seen the US warship, but his vessel’s Automatic Identification System (AIS) was not picking up any signals from the warship.

It was later determined that the McCain had not switched on its AIS – which reveals information such as a ship’s location, identity, speed and direction of travel – to other vessels in the area and monitoring stations.

The Alnic’s captain tried to contact the McCain, but there was no response. When he noticed the US warship drawing closer, at an acute angle, the captain of the Alnic, which had a Filipino crew, reportedly said sarcastically in Tagalog to his bridge team: “Good crossing action, in the middle of a channel.” He at first assumed that the warship would be able to pass safely.

Fearing a collision several moments later, he then ordered speed reduced but did not change direction or immediately try to stop his vessel. By the time he tried to stop completely, it was too late.

The TSIB report pointed out that the tanker captain had not alerted his crew to the danger of a collision and that he was not supported by enough manpower on the bridge.

The accident sparked a massive Singapore-led search at sea for the 10 US sailors who went missing. Their bodies were eventually recovered from the warship a few days later.

TSIB’s report is consistent with findings by the US Navy, which conducted its own investigations, the results of which were made public last November.

In its report, the US Navy noted that when the American vessel entered the congested channels, the commanding officer (CO) did not station extra manpower on the deck to help with navigation in the early hours of the morning, despite recommendations to do so from other officers.

The report laid most of the responsibility on CO Alfredo J. Sanchez, who was relieved of his duties last October, together with executive officer Jessie L. Sanchez. The report said: “In the navy, the responsibility of the commanding officer for his or her ship is absolute. Many of the decisions made that led to this incident were the result of poor judgment and decision-making of the commanding officer.”