Divers from the U.S. Naval Sea Systems Command (NAVSEA) and Southwest Regional Maintenance Center (SWRMC) have carried out the first full underwater waterjet seal and evaluation on a littoral combat ship (LCS), USS Fort Worth (LCS 3), the US Navy said yesterday.
NAVSEA’s Supervisor of Salvage and Diving (SUPSALV) was assigned to come up with a way of replacing at sea anodes installed on the LCS’s waterjets, instead of having to conduct the replacement in a dry dock.
Joe Theodorou, SUPSALV program manager said: “It is important to have this underwater process to provide a cost effective, timely, and manageable procedure to the LCS fleet. Having this capability saves the Navy $100 million in dry dock costs in the San Diego area.”
LCS class ships are driven by waterjet systems that use seawater to move the ship. Propelled by four water jets in addition to two diesel and two gas turbine engines, USS Fort Worth boasts a range of over 3,500 nautical miles.
As a result it is necessary to protect these waterjets from internal corrosion and anodes on the waterjets need to be inspected and replaced every four months.
SUPSALV engineers developed a plate to seal the waterjet inlet, as well as external patches to isolate the waterjet, creating a dry environment. This allowed maintenance teams to inspect and replace the zinc anodes while the ship was waterborne.
With the procedure complete for Freedom-variant littoral combat ships, SUPSALV plans to test the procedure on Independence-variant ships, since both classes use waterjets for propulsion. Testing on Independence variant ships is expected to complete by March 2014.
The LCS class, which includes a Freedom and Independence variant, features a very shallow draft allowing LCS to get closer to shore, a major advantage when operating in the littorals. This advantage could enable the Navy and Marine Corps to reduce V (CRRC) transit times from ship to shore while also allowing the CRRCs to remain within the protected umbrella of LCS fire support.
USS Fort Worth is outfitted with reconfigurable mission packages, which can be changed out quickly, and focus on three mission areas: mine countermeasures, surface warfare and anti-submarine warfare.
Press Release, January 3, 2014; Image: US NAVY