Navy officials in San Diego Monday were assessing the damage in the third major engine breakdown over the past year in a littoral combat ship, prompting an admiral to call for improvements in engineering oversight and training.
The Navy said a leak last month from a pump seal resulted in seawater entering the lube oil system of one of the ship's main propulsion diesel engines.
The incident occurred on July 11, but the Navy didn't release the information publicly until Sunday. The Freedom returned to San Diego under its own power two days later, and eventually participated in the Rim of the Pacific exercise while operating on its gas turbine engines.
One of the diesel engines will have to be rebuilt or replaced because of rust and seawater damage, the Navy said.
A statement said the cost and timeline for the repair are unknown and an investigation is underway to determine the cause of the breakdown.
Previous incidents damaged the propulsion systems of two other members of the LCS family, the USS Fort Worth and USS Milwaukee. The Fort Worth is on its way back to San Diego after being stuck in Singapore since January.
"Given the engineering casualties on USS Freedom and USS Fort Worth, I believe improvements in engineering oversight and training are necessary," said Vice Adm. Tom Rowden, commander of U.S. naval surface forces.
"The recently completed LCS review of manning, design, and training looked at a number of sailor performance and ownership factors, to include crew rotation, size and proficiency," Rowden said.
"From this work, I believe we will be able to make immediate changes to help reduce chance for future operator error. I am fully committed to ensuring that our ships and the sailors who man them have the proper tools and training they need to safely and effectively operate these ships."
The breakdown on the Fort Worth stemmed from a lack of engine lubrication, according to a Navy investigation.
The commander of the crew onboard the Fort Worth at the time was relieved. The LCS operates with rotating crews so the ships can be deployed overseas for longer periods of time.