Since its first days at sea, the first Littoral Combat Ship (LCS-1), the USS Freedom, has had trouble with its ship service diesel generators (SSDGs). Now the U.S. Navy says it is working to get those problems solved.

“The SSDGs,” says Navy Undersecretary Sean Stackley, are “probably the most significant design deficiency we’re dealing with today. We do have reliability issues that we have identified. We have fixes in place on the follow ships. As LCS-1 continues its deployment, we’ll be incorporating those fixes on LCS-1 to address that issue.”

The generators simply are not doing the job they are meant to do, Stackley said July 25 during a House Armed Services seapower subcommittee hearing on the LCS program.

“First the requirement,” he says. “Those generators are required to perform at 800 hours of operation between failures. Today, our experience is 450 hours between failures. So that’s the symptom of the problem.”

The Navy has three known Freedom SSDG issues, he says, “one associated with the governor on the generator, one associated with the cooler that goes with the generator and one associated with the size of the piping that’s associated with coolant flow.”

There are fixes for all three problems, he says. “They’re not all incorporated into LCS-1 today, but they’re all being incorporated on the follow ships of that variant. Today we are working through these interruptions in terms of the ship’s operations, if you will, to [accommodate] these failures. We’ve got to fix that.”

The good news, he says, is that the ship is designed with four diesel generators. “It requires two under operations plus one in standby. So there’s redundancy in the system to overcome some of the shortfall in the operational availability, and there are fixes in place.

“Those fixes are largely contained [in] that package unit that shows up from the vendor, and they’re being incorporated by the vendor. The impact on the ship side will be minimized.”

SSDG problems have sidelined the Freedom during its relatively short career in the fleet, most recently causing the ship to lose propulsion shortly after it left the pier for an exercise off Singapore, where LCS-1 is deployed.

The SSDG issues caused power outages during the Freedom’s transit to Guam, Navy officials acknowledge. The issue appears similar to problems the Freedom experienced while operating in Central American waters, according to documentation obtained by the Aviation Week Intelligence Network. An AWIN review of mishap reports and engineering logs reveals reliability and related issues with those generators through the beginning of this decade.

Addressing historical power outages on the Freedom, Navy officials previously say such incidents are not uncommon with naval vessels. But Vice Adm. Richard Hunt, Navy director of staff and head of the LCS Council of Admirals overseeing the program, tells AWIN that with time and experience such incidents should become fewer. “It will become more reliable,” he says. However, generally speaking, “diesels are really reliable; they shouldn’t go up and down,” he says.