fabrication cost and schedule risk and makes inspection easier, resulting in a cost savings of approximately $87,000.
Brackets for Launch, Recovery and Handling System Crane
Te current fabricated bracket
design for the launch, recovery and handling system (LRHS) crane on the Freedom LCS requires precision fabrication, welding and machining and must meet stringent dimensional tolerances. Te crane is used to launch, recover and handle offboard vehicles. Te Navy Metalworking Center
worked with Oldenburg Group Inc., which supplied the brackets, as well as Lockheed Martin and Computer Sci- ences Corp., to redesign the brackets as cast steel components for signifi- cantly reduced cost and weight over the welded fabrication. The project created seven potential casting designs that would survive expected static and dynamic load conditions. According to Akans, the cast design had to be a one-for-one drop-in replacement, using the same material as the weld-
The cast bracket for the launch, recovery and handling system crane on the Freedom variant of the Navy’s littoral combat ship is estimated to reduce costs by 77%.
ment, which was fabricated from a high strength steel alloy. “In most cases, as long as the new design doesn’t require complete re- qualification and a long list of Navy approvals (i.e., a one-for-one drop- in replacement that doesn’t affect fit, form and function), the decision to pursue the candidate solution is fairly straightforward,” he said. “When re-qualification (i.e., shock testing) is involved, the decision to move forward with the new design is much more difficult to justify.” Once the cast designs were established, the team modeled the
casting process to optimize designs and processing conditions. Based on the models, the team selected two of the designs for further evaluation and provided them to Oldenburg Group for implementation. Oldenburg Group plans to con- duct validation trials on the brackets this year. Four American Bureau of Shipping (ABS)-approved met- alcasting facilities were identified to supply the brackets. After providing a statement of work, detailed draw- ings and specifications to produce the castings to the potential sup- pliers, Oldenburg Group selected a metalcasting facility to produce the initial cast brackets and will be plac- ing an order this summer. Based on current Oldenburg
Group production experience with the legacy fabricated design and the estimated cost to implement the cast designs for a full ship set of 26 brackets, a cost reduction is antici- pated to be more than 50%. The cast design also will be 33% lighter and use fewer fasteners than the legacy fabricated version.
The littoral combat ship is designed to be fast and have excellent maneuverability to defend against threats in coastal waters. August 2014 MODERN CASTING | 53
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