As the Littoral Combat Ship ( ) USS Freedom got under way in late November for ship-and-crew-deployment certification trials, it was clear that the LCS program team had made a priority of fixing some major ship issues noted earlier in the year by Aviation Week during an unsanctioned guided tour of the ship while it was in a U.S. Navy dry dock in San Diego.
After first denying the veracity of many of Aviation Week’s observations, Navy officials said they would make repairs for most of the problems a priority. Most of the major issues have been fixed or are scheduled to be addressed.
For example, Aviation Week had noted extensive corrosion throughout many parts of the ship. “LCS-1 was designed and built with an active anti-corrosion system, which was further extended during post-delivery to address additional areas of concern,” the Navy says. “This system is in the baseline for LCS-3 and follow hulls. Minor corrosion was also experienced in limited areas of the ship, which have been addressed through modifications to the paint schedule and material … [which also] are in the baseline for LCS-3 and follow hulls.”
Also, during Post Shakedown Availability 2 (PSA-2), the main machinery room was completely repainted and additional preservation measures were implemented, including painting the piping that had not been previously painted, the Navy says.
Aviation Week also had noted pinprick holes and leak damage in critical piping systems. “The shipbuilder performed non-destructive testing (NDT) as required and utilized acceptance criteria that conformed to Naval Vessel Rules,” the Navy says.
Marinette Marine, LCS-1 prime contractor’s shipyard partner, relies upon a vendor to conduct radiographic testing (RT), the Navy says, adding that the vendor’s procedure for RT on LCS-1 was reviewed and approved by the American Bureau of Shipping. The vendor performed RT of all of the water mist weld joints in January 2007, with the results and films reviewed by ABS.
The Navy says it has “since found that the manner in which the [RT] was accomplished during construction did not highlight the defects.” As a result, the Navy says, “weld procedures and NDT procedures have been changed on LCS-3 and follow [ships], including increased Navy quality assurance.”
The gas-turbine engine intakes were redesigned and “improved mating seals” were installed on the ship, as well as later Freedom-class models, to prevent the cascade of issues that caused the starboard engine to fail through corrosion-induced metal fatigue.
Freedom program officials also redesigned the Isotta Fraschini ship’s service diesel engines (SSDGs) to address “performance issues” documented during Freedom’s early deployment. An Aviation Week review of casualty reports and engineering logs reveal reliability and related issues with those engines through the beginning of this decade.
The Navy modified the Freedom’s RIX air compressors to make them more reliable, and the ship’s compressors are being evaluated for replacement with new Sauer air compressors that were included in redesigns for follow-on LCS-1 class vessels.
Ship sources say compressor reliability remains an issue. Initial LCS requirements called for the ship’s compressors to run 50% of the time, but they are running closer to 90% to compensate for the large-scale leaking of pipes and welds, according to a source intimately familiar with Freedom’s operations. The Navy says the new compressors are similar to the systems employed onships.
The source says, “Experience operating the Sauer air-cooled compressors indicates they overheat in hot climates — will shut down due to their location in the Freedom-class main machinery space, which is not air-conditioned.” The system, the source notes, has not yet been tested while deployed to warm-weather climates.
In response, the Navy says, “The Sauer system meets all operational and maintenance requirements.”
The Navy also redesigned the reduction gear oil sump covers to stop oil from running down the exterior casing and into the bilge.
“The initial gear design did not have securing mechanisms for the covers to protect the gears from intrusion,” the Navy says. “The original covers were modified to allow them to be locked. This impacted the sealing of the covers. The covers were subsequently redesigned. The redesigned covers are installed on LCS-1, LCS-3 and incorporated into the LCS-5 and follow baseline.”
The Navy has corrected deficient pipe hangars aboard the Freedom and modified LCS-3 drawings and updated that ship’s construction to “include details and guidance for installation on future hulls.”
Program officials have repaired Freedom’s fin stabilizers, which “show poor reliability. This system is currently under evaluation and may not be required to meet performance requirements.”
The Navy now asks dockmasters to move their Yokohama pier fenders for the SSDG engine exhaust “away from exhaust ports, which has mitigated the hazard to wooden piers.”
The exhaust, the source familiar with Freedom’s operations says, has lit wooden piers and other structures on fire.