Composite Material Used in Tailcone of Virginia-class Submarine

Engineers at Naval Surface Warfare Center (NSWC) Carderock Division, in conjunction with the Office of Naval Research (ONR), Program Executive Office (PEO) Submarines and industry, have designed, built, and installed a fiber-reinforced polymer composite tailcone on USS Mississippi (SSN 782), commissioned June 2.

This new tailcone takes the place of a traditional metallic unit and is less expensive to build, install, maintain, and it reduces the ship's overall weight. Mississippi's commisioning was held in Pascagoula, Miss. and it is the Navy's ninth Virginia-class submarine

"Through years of research and development, we've identified a process where we can build tailcones for new submarines using composite materials which weigh less and are more resistant to corrosion," said Craig Madden, an ocean engineer at NSWC Carderock Division. "The lighter, less expensive composite materials have significant potential savings in total ownership cost for the Navy."

The tailcone of a Virginia-class submarine extends aft from the propulsor hub and traditionally has been made from metallic materials that require extensive cutting, shaping, welding, and machining which required up to a year to complete. Using composite materials, Mississippi's tailcone delivered in less than seven months which included the time it took to make the initial mold. With a precisely-built mold now available, the time to make composite tailcones could be as little as four months and will ensure that each one has identical dimensions.

Madden said more work is necessary to understand the influence of composite fabrication methods and material selection on the design and procurement processes.

"There is a need for composites," he explained. "Using composites instead of metal is not a straightforward substitution, and we need to make the replacement for a good reason. We have developed the capability to successfully use composites in both the Virginia and Seawolf classes."

NSWC Carderock Division's responsibilities span a broad range including science and technology (S&T), research and development (R&D), test and evaluation (T&E), product delivery and Fleet support. Specifically, NSWC Carderock Division leads the Navy in hull, mechanical and electrical engineering expertise and delivers technical solutions in order to build and sustain a dominant, ready and affordable fleet. Headquartered in West Bethesda, Md., approximately 3,500 scientists, engineers, technicians and support personnel are located across the U.S., which includes the Ship Systems Engineering Station in Philadelphia.

By William Palmer, Naval Surface Warfare Center Carderock Division Public Affairs

Source: US navy
Date: Aug 10, 2012