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Report: U.S. Navy's Freedom-Class LCS Can Run, But at Lower Speed

USS Sioux City under way in the Red Sea
USS Sioux City in the Red Sea, July 30 (USN)

Published Oct 6, 2022 11:07 PM by The Maritime Executive

The U.S. Navy has a way to use its fast Freedom-class littoral combat ships even without fixing a faulty gearbox, the service said this week - but it would need to accept a reduction in the extra-high top speed that characterized the class.

The Freedom-class LCS USS Sioux City has just returned from a successful five-month deployment to the Middle East and back, marking the first time that one of the vessels has deployed to the region. Though she underwent some maintenance during the voyage, she carried out the mission without the well-publicized propulsion issues which have plagued the class, according to Defense News.

The difference this time, her command says, was a series of careful engineering protocols that avoid damaging the vulnerable bearings on the combining gear's clutch. 

The Freedom-class has had to avoid the diesel-plus-turbine top power mode its designers used to meet the Navy requirements, which called for a 40-plus knot top speed. This blistering-fast requirement was a major factor behind the decision to armor and arm the LCS lightly, balancing its lethality and survivability with speed. 

When the Navy first concluded that it had a class-wide issue with the gearbox, it ordered the existing Freedom-class fleet to stop using the combined diesel and gas mode. It later banned a second mode - the all-diesel "boost" setting - after finding that the torque could cause similar gearbox problems, an official told Defense News last year.

The Freedom-class vessels have been operating with these restrictions successfully in the U.S. 4th Fleet area of operations (Caribbean and Eastern Pacific) ever since, helping the U.S. Coast Guard intercept drug-runners. USS Sioux City's recent overseas deployment proves that the slow-steaming adaptation works for long-range operation, her commanding officer and commodore told Breaking Defense. "From my perspective over all these ships, we’ve really put that problem behind us," said Capt. David Miller, commodore of LCS Squadron 2.

The Navy has asked to decommission nine Freedom-class LCS vessels next year, including USS Sioux City, if it can secure permission from Congress. The House and Senate versions of the must-pass defense spending bill for FY2023 would allow the service to let go of four of the hulls but require keeping five.

Sioux City is also in line to have her combining gear fixed at an upcoming yard period, according to USNI, which would remove her speed restrictions.