A faulty shaft seal assembly is suspected as the main cause behind water leaks on the USS Freedom (LCS-1) earlier this year, but the Navy believes the problem is isolated to a water jet on that ship, Naval Sea Systems Command (NAVSEA) said.

“The mostly likely cause was a deficiency in the seal assembly,” NAVSEA spokesman Chris Johnson said, adding a final conclusion was still pending.

“Engineers are looking at root cause analysis right now and will make a final determination in the near future,” he said.

The Freedom was placed into dry dock in San Diego for repairs on Feb. 25 after suffering a leak of the shaft seal off the coast of California earlier that month. It was another problem for a ship that experienced hull cracking and required repairs last year.

The seal was repaired and the Lockheed Martin [LMT]-built ship was removed from dry dock last week, Doug Laurendeau, the company’s vice president for Littoral Combat Ship business development, told reporters Friday.

Johnson said inspections of the shaft seals on the other three water jets found no problems, as was the case with examination of the Fort Worth (LCS-3), which is poised for Navy acceptance trials later this month after recently completing its second builder’s trial.

“We tested them over two series of builder’s trails and they have not shown the same issue,” Johnson said.

Rear Adm. James Murdoch, the program executive officer LCS, told Defense Daily in an interview last month that the shaft seal failure would not require a redesign.

Murdoch said it would have been possible to repair the Freedom while keeping it in the water, but because it was the first in the class putting it in dry dock was the best option for an “end-to-end” examination.

Lockheed Martin is the prime contractor for the Freedom design along with Wisconsin-based partner Marinette Marine. Austal USA in Mobile, Alabama is building the second variant of the LCS, with the USS Independence (LCS-2) as the lead vessel.