The Navy is implementing specific design and engineering improvements to its Littoral Combat Ship following the construction of the first two vessels, the Freedom and the Independence.
The changes to LCS span a range of areas from adjustments to water jets to efforts to fight corrosion and improve the ships elevators, deck extensions and inflatable rafts.
Vice Adm. Willy Hilarides, commander of Naval Sea Systems Command, said the first two LCS ships were built with a specific mind to continued development of the platform for the long term.
“We forget that we decided to take LCS 1 and 2 and deliver them as ships to the fleet, long before the design was mature -- so that we design the right class of ships for the long term,” Hilarides said. “There are 10 to 12 big changes to the ships that are in place. That is what we intended to do.”
The Navy plans to build and acquire as many as 32 of the controversial shallow-water, multi-mission ships engineered for surface warfare, countermine warfare and anti-submarine warfare. The LCS has come under fire from lawmakers, analysts and even members of the Navy for not sufficiently meeting mission requirements or being survivable enough to withstand anticipated threats.
However, proponents of the platform have long maintained the ship brings substantial mission-enhancing technologies to the Navy. Most of all, they say the platform has been engineered to adapt, meaning it is built to accommodate new technologies as they emerge.
The LCS class consists of two variants, the Freedom and Independence - designed and built by two industry teams led by Lockheed Martin and an Austal USA-led team. Contracts were awarded to Lockheed Martin and Austal USA on December 29, 2010, for the construction of up to 10 ships each.
So far, the first four ships have been commissioned with the fourth, the USS Coronado, being commissioned in April, Naval Sea Systems Command officials said. LCS 5 and 6 launched in December of last year, and ships 7 through 16 are in some stage of production, Navy spokesman Matthew Leonard added.
The Navy hopes to build as many as three LCS per year, however that remains unclear in light of Congressional mark-ups of the budget, some of which have lowered the amount to two per year.
Some of the improvements to the Freedom variant of the LCS emerged as a result of experiences on-board the Freedom during its recent deployment. Identifying and fixing problems with the ship is part of what the deployment was designed to accomplish, Hilarides explained.
The Freedom experienced problems with its ship service diesel generators, or SSDGs, which resulted in a temporary power outage during a trip to Guam in the summer of last year. The ship also experienced problems with a corroded cable and faulty air compressor, Navy officials added. Overall, LCS 1 continues to receive a series of modifications which will improve the USS Freedom as well as the remaining LCS Freedom–class ships now being built and developed.
One such change resulted in what’s called an anchor windlass replacement, said Naval Sea Systems Command spokesman Dale Eng.
“To prevent water ingestion in the anchor windlass room, the existing anchor winch, hydraulic unit and mooring capstan were replaced with a single electric capstan (chain) winch on the main deck. In addition, the existing towing chain was replaced with a lighter chain,” he said.
Also, to improve corrosion protection, the ship’s Impressed Current Cathodic Protection system was modified by adding protections to the water jet inlet tunnel; Cathodic Protection is a technique used to control or minimize the corrosion of a metal surface. This change, designed to improve reliability and maintainability, was put into effect on LCS 3, LCS 5 and follow on ships, Eng said.
Other changes put into effect starting on LCS 3 include the lengthening of the stern transom and the integration of the buoyancy tanks into the stern of the hull. The transom stern is the bottom tip of the surface of the stern that approximates the waterline.
“These changes increase the weight service life margin and enhance the ship's stability characteristics,” Eng added.
The ship’s water jets were modified as well, changing from a mixed flow design to an axial flow in order to reduce cavitation (air pockets) and improve efficiency. With an axial flow, water is pushed in a direction parallel to the shaft of the impeller, a type of propeller.
The end result of implementation of the axial flow water jets is improved operation efficiency with reduced maintenance intervals, Eng said.
Also on the Freedom variant of the LCS, engineers have moved to a significantly less complex gas turbine electric start system on LCS 5, in order to reduce costs and lower ship weight, he added.
There have been substantial changes to the Independence variants of the LCS as well, including the installation of what’s called bridge wings, narrow walkway extensions designed to improve safety. Also, the 5.1 meter Rigid Hull Inflatable Boat, or RHIB, on the Independence variant was replaced with a Navy standard 7 meter RHIB. The new Navy RHIB is designed to provide improved performance and supportability, Eng said. The change was made to LCS 4 and follow on ships in the fleet.
Similar to their Freedom variant counterparts, the Independence-class ships of the LCS are also getting an improved cathodic protection system designed to combat corrosion. This effort is being built onto LCS 4 and follow-on Independence variant ships.
The Independence-variant ships are also getting upgraded water jets quite similar to their Freedom counterparts. The jets are being upgraded to handle the horsepower provided by the gas turbine, Eng said.
The Navy is also improving the anchor on the Independence ships through what’s called the winch control system, an effort to modulate the motion of the anchor and reduce the reliance on manual hand brakes.
“The variable control will make it safer to operate for the crew and the equipment. Other changes enhanced the ability to safely spool anchor cable and have reduced the wear on the ship's bolster and anchor winch,” Eng added.
The Independence variant has also redesigned the mission bay side door of the ship to improve reliability and reconfigured the platform lift elevator such that it can better handle weapons and ordnance, Eng said.