U.S. Navy and officials contest the findings of service and contractor reports from last year indicating that the cracking and engine problems on the Freedom-class Littoral Combat Ship ( ) were far worse than the program initially acknowledged, and say those issues have been fixed.
The Aviation Week Intelligence Network (AWIN) was granted exclusive access to the reports, which service officials say they do not know about and could be outdated. Click here for a story on the content of the reports and leading naval analysts' reactions.
There are two very different LCS designs: LCS-1, developed and produced by an industry team led by Lockheed Martin, and, developed and produced by a team led by .
While analysts, Navy officials and government watchdogs say both ship variants have development issues, the reports reviewed by AWIN and the information provided to naval analysts for comment deal solely with LCS-1.
Lockheed Martin and the Navy say the Freedom has since been repaired and upgraded to address the issues identified during that time and is scheduled to be redelivered to Naval Sea Systems Command (Navsea) soon with an eye toward re-evaluating its operational limitations.
“USS Freedom was delivered in 2008 and since that time has spent all of her time either deployed or in testing phases for the Navy,” says Joe North, vice president of Littoral Ship Systems for Lockheed Martin Mission Systems & Sensors. “As the lead ship in a totally new class, she has been through extensive testing and been certified and approved by both the Navy as well as the American Bureau of Shipbuilding.”
The ship, North notes, has logged 55,000 nm, is operational, and “continues to perform well and meets all requirements ... Freedom has finished her formal post-delivery availability and we are in full stride preparing for deployment.”
Navsea also says the ship’s problems lie astern.
“Navsea isn’t familiar with any new official ‘reports,’ either from Navy or industry sources, indicating the issues [are] either new or as alarming [as indicated],” said Navsea spokesman Christopher Johnson when asked about the reports’ findings and analysts’ conclusions.
“Most of these issues, such as the cracking and MT30 damage on LCS-1 and the minor corrosion discovered on LCS-2, were well reported early last year, when we first provided statements to media.”
The media release on LCS-1 cracking cited by Johnson tells of a single crack 6.25 in. long on the outside of the hull and 3 in. long on the inside of the hull about 3 ft. below the waterline around the middle of the ship.
The crack, Navsea says, originated in a weld seam between two of the ship’s steel plates. Repairs were completed March 12, 2011. A “detailed analysis” conducted by Navsea and the American Bureau of Shipping and industry “indicated a contributing factor for the crack was likely a weld defect,” Johnson says.
Lockheed’s North says, “There was a crack identified in the hull of the USS Freedom last spring, but at no time was the structural integrity of the ship compromised.”
Another “contributing factor,” according to Johnson, was undersized backing chocks exposing that area to higher-than-expected stresses. The chocks were replaced and the Navy identified design changes on LCS-3 to help alleviate the problems. LCS-5 is due to incorporate even more design changes, Navsea says.
Lockheed’s North now says, “There are no missing chocks,” adding the ship is designed “to meet all U.S. Navy requirements.”
Navsea said at the time, “No further design-related hull-cracking risk for the Freedom variant ships are expected.”
The reports AWIN gained access to suggest otherwise. They include pictures of 17 cracks; one was more than 18 in. long, some continued to grow despite “mitigation” efforts to stop them, another spiderwebbed across the surface and one was below the waterline.
“We have no knowledge of ‘spiderweb cracks’ or an 18-inch crack,” North says. “Freedom contains hundreds of miles of welds and thousands of joints — this single hull crack was fixed and has not caused a problem on the ship. For any first-in-class ship, that is a very good scorecard.”
Navsea’s Johnson says it is “patently false” to say the ship has any current speed restrictions on it. The reports indicated the ship was limited to a “safe operating envelope” in which it could travel no faster than a laden cargo freighter in sea-state 5 conditions, i.e., waves of 8.2 to 13.1 ft.
“Following the hull crack event aboard Freedom last year, the operating speed was reduced during the transit to home port for repairs,” he says. “Since the repairs and subsequent inspection, LCS-1 is approved to operate within the full scope of the designed safe operating envelope.”
Lockheed’s North says, “The crack previously disclosed occurred during sea trials and when the ship encountered heavy seas, she was limited in speed for safety. This is standard practice. There have been no speed restrictions or limitations on the ship since that time and she is fully operational.”
The officials also deny any issues related to the aluminum-steel ship composition. “USS Freedom’s hull is steel,” North says. “The deckhouse is aluminum and they are joined with a bond that has not resulted in any bimetallic issues.”
Four of the cracks, including the 18-plus-in. crack, are just above bimetallic strips, according to the reports.
Navsea’s Johnson says the ship was designed and built with an active anti-corrosion system, which was further upgraded recently “to address additional areas” of concern.
“This system is in the baseline for LCS-3 and follow hulls,” he says. “Minor corrosion was experienced in limited areas of the ship, which have been addressed through modifications to the paint schedule and material. These modifications are in the baseline for LCS-3 and follow hulls.”
Navsea notes LCS-2 has corrosion problems as well, which Johnson says are being addressed. “The vessel is 127 meters long and the corrosion was limited to an area 30 centimeters in diameter,” he says. “In the short term, the issue was mitigated by installing doubler plates 360 degrees around the exterior of all four water jet tunnel cone assemblies (interior to the ship) as well as a portion of the tunnels where the majority of the pitting appears to be occurring.”
The long-term solution is to fully repair the existing corrosion damage and install a Cathodic Protection System in both the cone assemblies and the water jet tunnels, he says.
The design work for the protection system was started in 2010, he says. The full system design will be installed during the dry-docking portion of the ship’s Post Shakedown Availability in 2012.
The waterborne portion of the system was installed on LCS-4 prior to launch, according to Johnson.
The protection system is included in the baseline design for LCS-6 and follow-on ships.
Regarding the failure of aTrent MT30001 gas turbine engine, Johnson cites an earlier release saying, “The root cause analysis of the engine failure revealed that the gas turbine intakes were allowing saltwater to be ingested into the engine during high seas evolutions, which lead to the eventual failure of an HP [high pressure] turbine blade. The saltwater did not induce corrosion internal to the engine. However, it changed the air flow through the engine, which eventually led to the failure.”
Navsea’s Johnson says, “As a result of the failure, a redesign of the intake structure along with improved mating seals were implemented on LCS-1 on post delivery and are in line for LCS-3 and subsequent ships.”
Navy officials acknowledge that the proof that the LCS-1 fixes work will be when it goes back into the water for tests and operations.
Service plans have included an LCS fleet of about 55 ships costing more than $30 billion to buy. Defense Secretary Leon Panetta detailed plans Jan. 26 to base LCS ships in Singapore, but reduce the planned procurement by two over the next five years.