The USS Lake Champlain is shown here in the Pacific region in April. (Photo by Mass Communication Specialist 3rd Class Kelsey L. Adams/ Navy)

A U.S. ship assigned to protect an American aircraft carrier off the Korean Peninsula collided with a commercial fishing boat after losing track of it on radar and attempting “improper and untimely maneuvers” in an attempt to avoid a wreck, the Navy said in report released Thursday.

The May 9 collision of the USS Lake Champlain, a guided-missile cruiser, was one of four major incidents for Navy ships in the Pacific this year, including two that left 17 sailors dead. The incidents have prompted broad scrutiny of the Navy’s seamanship, training, deployment schedules and oversight by senior officials.

The Champlain, a 567-foot-long cruiser, collided with the 60-foot South Korean fishing ship Nam Yang 502 in the Sea of Japan at 11:51 a.m., 16 minutes after the Champlain lost track of the smaller boat. The cruiser’s crew ordered a hard turn of 30 degrees first to the right, and then to the left, ultimately striking the Nam Yang 502. The South Korean vessel’s bow, or front, struck the Champlain’s port, or left, side.

The collision created a 3-by-5-foot dent on Lake Champlain, before the South Korean ship pivoted to its right and scraped the ship’s side. U.S. sailors inside reported a bulge on an inside wall, or bulkhead, of the ship, but the vessel did not take on water and no one was injured, the report said.

This graphic included in a navy report shows how the USS Lake Champlain, a guided-missile cruiser, and a South Korean fishing vessel collided with each other May 9. (Navy image)

This graphic in a Navy report shows the location and ship track of the USS Lake Champlain, a guided-missile cruiser, before and after it struck a South Korean fishing vessel on May 9. The Navy ship was accompanying the USS Carl Vinson, an aircraft carrier, at the time of the mishap. (Navy image)

At the time of the collision, the Lake Champlain was operating in formation with the USS Carl Vinson, an aircraft carrier, and the ROKS Yangmanchun, a South Korean destroyer. The Lake Champlain and Yangmanchun provided security for the carrier, with the Champlain posted to the southwest and the Yangmanchun to the northeast.

The report cited “numerous failures” by Navy personnel standing watch on the Lake Champlain, including an inability to adhere to “sound navigation practices,” use available tools at their disposal, such as radar, and respond effectively when in danger of a collision.

The report, while not focusing on the South Korean vessel’s actions, also noted that the Nam Yang 502’s global positioning system and radio were not functional, contributing to the collision. Lake Champlain crew members tried to reach the ship several times prior to the mishap to establish where each other were.

The Navy released a brief description of the collision in a report Nov. 1 that detailed a broad review of Navy operations in the Pacific. It was called for this summer by Adm. John Richardson, the service’s top officer, after the destroyers USS Fitzgerald and the USS John S. McCain experienced catastrophic collisions June 17 and Aug. 21, respectively. The Fitzgerald accident killed seven sailors off the southern coast of Japan, while the McCain collision killed 10 sailors near Singapore.

The Navy had declined numerous Freedom of Information Act requests to release a report detailing the Lake Champlain investigation, citing open litigation. Richardson, when asked at a Nov. 2 news conference, committed to releasing a more detailed report about the Champlain.

The collisions of the Fitzgerald and the McCain prompted senior Navy officials to fire their commanding officers. The top officer of the Lake Champlain at the time of its mishap, Capt. Chris Cegielski, kept his job until September, when he rotated out in typical fashion.

The report released Thursday said that Cegielski was away from his ship on a regularly scheduled meeting on the Carl Vinson when the collision occurred. That left in charge his executive officer, the second in command, who was not on the ship’s bridge and was not notified of the danger the Lake Champlain faced “until seconds before impact.”

Investigators faulted lower-ranking officers on the ship’s bridge, especially the officer of the deck, for not communicating with others. In particular, the officer of the deck was required to call the executive officer, but did not do so on multiple occasions, the report said.