A sudden lurch left by the guided-missile destroyer John S. McCain shortly before dawn on Aug. 21 put it on a collision course with a commercial oil tanker and caused the deaths of 10 American sailors, an official Singapore investigation determined.

A final report released Thursday by Singapore’s Transport Safety Investigation Bureau echoed a U.S. Navy study, concluding that “a series of missteps” by inexperienced and possibly poorly trained sailors aboard the McCain during a botched transfer of propulsion controls put it in the path of the Liberian-flagged Alnic MC.

The bridge team of the Alnic MC had spotted the destroyer turning but assumed it would safely pass their vessel, a calculation proved wrong three minutes later when they crashed a little more than five miles from the entrance to the Singapore Strait.

Although the McCain’s movement caused the mishap, Singapore investigators also ruled that “the actions taken by Alnic MC were insufficient to avoid the collision.”

Around 5 a.m. on the morning of the crash, the Alnic MC’s skipper overheard Singapore pilots radioing an American warship but it had not been sighted by his crew or picked up on the tanker’s radar.

The Strait is one of the world’s busiest waterways, so it wasn’t unusual that the Alnic MC’s crew first saw a Chinese asphalt tanker about a half-mile away overtaking their slow vessel from their right, plus a British-flagged container ship approaching from their left.

The other ship they finally spotted was the McCain, closing fast from their right. The Philippine skipper began to radio the destroyer in English but drew no response. It seemed to be taking an acute and fast angle to pass his merchant vessel.

“Good crossing action, in the middle of a channel?” he was recorded saying sarcastically in Tagalog.

To let the McCain by, he ordered his vessel to slow to half-engines but slightly more than a minute later the Alnic MC’s bow hit the left side of the McCain. It speared through the warship’s steel bulkhead, flooding seawater into the berthing quarters where the 10 sailors drowned.

Singapore investigators determined that the McCain’s crew never made any light or sound signals to attract the Alnic MC’s attention and the warship’s data recorder never acquired the commercial vessel as a target.

Investigators faulted the McCain for a “lack of experienced personnel handling critical equipment like steering and propulsion,” which to them also suggested a lack of proper risk assessment by the ship’s leaders for transiting the bustling Strait.

“While there was no evidence of a panic on the bridge of (McCain), it is likely that there was a lack of a comprehensive situational awareness amongst the team on what was to come,” the report stated.

The McCain collision capped nearly eight months of mishaps involving American warships. They included the June 17 crash of the sister destroyer Fitzgerald with the commercial vessel ACX Crystal in the Philippine Sea that killed seven American sailors.

Those collisions had been preceded by a Jan. 31 accident in which the cruiser Antietam ran aground on rocks lining the Japanese coast. Less than five months later, the San Diego-based cruiser Lake Champlain collided with a South Korean fishing boat, but those incidents weren’t fatal.

In the wake of the McCain crash, the chief of naval operations, Adm. John Richardson, vowed to reform the surface warfare fleet, triggering deep changes designed to hike the amount of sleep sailors receive, revamp their schooling and credentialing and ensure no ship leaves port with a poorly trained crew.

©2018 The San Diego Union-Tribune. Distributed by Tribune Content Agency, LLC.