rent modular build plan for LCS. Marinette Marine Corp. procured
The cast stem (the curved piece making the edge of the upside down bow) allows for improved fit-up and accessibility to adjoining structural members. The bow module shown here was installed on the LCS-3.
sibility needs, the casting suppliers’ manufacturability concerns and the ABS’s performance requirements. To ease casting construction, the cast stem was split into multiple
castable pieces to reduce molding material requirements. Tis allowed the shipyard to adjust the cast stem fit-up to structural components and facilitated incorporation into the cur-
the cast stem from St. Louis-based Schoellhorn-Albrecht for installa- tion on the bow section of the second Freedom-variant LCS, the USS Ft. Worth (LCS-3). If one were to compare just the cast stem to the fabricated stem bar it re- placed, the cast stem would cost more. But the added value of substantially reducing installation costs compared to the baseline method makes up for the difference. Additionally, the improved design allows for easier connection with the hull plates and reduced pro- duction time for the bow. “Te factors that go into a typical Business Case Analysis [for converting to casting] are pretty standard—the costs to produce and qualify the new solution compared with the expected benefits (labor, scrap and rework reduction, schedule impact, etc.) are typically the main factors,” Akans said. Ultimately, the cast stem reduces
fabrication cost and schedule risk and makes inspection easier, result- ing in a cost savings of approximate- ly $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. The Navy Metalworking Center
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%.
22 | METAL CASTING DESIGN & PURCHASING | Jul/Aug 2014
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