The littoral combat ship is designed to be fast and have excellent maneuverability to defend against threats in coastal waters.
tive metalworking and manufacturing solutions and is operated by Concur- rent Technologies Corp., a nonprofit applied scientific R&D professional services organization. Since the launch of the first LCS
in 2008, the ManTech program has invested millions of dollars in projects to improve the capability and cost efficiency of the ships. Following are three casting conversion examples that have saved considerable time and money in building the Navy vessels. “Candidate projects for ManTech funding are generally proposed by the shipyard, although they can be identi- fied by the Navy Program Offices and/or technical codes,” said Robert
E. Akans, senior technical director, Navy Metalworking Center. “In the case of these three projects, the issues were brought forward by the shipyard (Marinette Marine Corp.) and the ship design prime contractor (Lock- heed Martin).”
Waterjet Inlet Tunnel Entry Edge Littoral Combat Ships are driven
by waterjet systems instead of pro- pellers for higher speed. According to the Naval Sea Systems Com- mand, each waterjet draws seawater in through a duct, increases the water’s pressure and then ejects it, causing the ship to move. During production of the first
20 | METAL CASTING DESIGN & PURCHASING | Jul/Aug 2014
LCS, the waterjet inlet tunnel’s leading edge was made by welding 13 formed steel plates to the ship’s hull. Due to the production challenges of correctly positioning each plate while account- ing for welding distortion, installation of the edge became costly and required more production time than expected. Shipbuilders spent many hours grind- ing the welded structure into the acceptable hydrodynamic shape. “Generally, the shipyard has tar-
geted fabrication times and labor costs planned for the fabrication/installation of critical components,” Akans said. “When these targets are significantly exceeded beyond what was planned, the ‘red flag’ is generally raised. Tis is
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