Navy explores exotic shapes, materials for LCS

Sea Power, May 2003 by Keeter, Hunter

The Navy's design criteria for its Littoral Combat Ships (LCSs) are pushing contractors to consider hull forms and materials rarely used in U.S. warships. Time will tell if the Navy will end up with a trimaran or a hull made of sandwiched composites. But these are among the options being assessed.

The Navy has asked firms bidding for the Littoral Combat Ship (LCS) program to develop a class of fast, stealthy surface warships, and to consider the advantages of hightech materials in their hull designs.

The new class of ships is to have a draft of 20 feet or less, an innovative hull form and propulsion system that will enable LCS to operate at economical loiter speeds and to conduct high speed sprints 50 knots or more.

Rear Adm. Charles S. Hamilton II, deputy program executive officer for ships, told Sea Power that the task of developing a ship that will remain stable in variable conditions at up to 60 knots speed presents "interesting trade space" for the designers in the selection of their materials. For example, the Navy wants the basic LCS hull to accommodate "modular" payloads and meet its core criteria for speed, self-defense, and stability. This may lead to designs and manufacturing processes more akin to the production of aircraft than traditional shipbuilding.

"Structural strength, sea-keeping and stability at higher and lower speeds ... are all factors affected variously by choices in hull form, such as catamarans, trimarans, and mono-hulls, [as well as in] materials, such as steel, honeycombed aluminum, solid and sandwiched composites [and so on,]" Hamilton said during an interview at his Naval Sea Systems Command (NAVSEA) office at the Washington Navy Yard.

Navy Looks to Aviation Industry for New Ideas

Many of the advanced concepts in hull form and materials the Navy and the LCS contractors are assessing come from commercial industry where high-speed ferries, for example, have pointed the way to new design options for fast logistics craft. "We are also interested in what the commercial aviation community has that may be relevant to this [LCS effort]," Hamilton said.

Many of the larger defense firms, such as General Dynamics (GD), Lockheed Martin, Northrop Grumman, and Raytheon, also are involved in the manufacture of advanced tactical, training, or transport aircraft. The designs of many modern planes incorporate the use of composites and specialized aluminum structures to reduce weight and increase strength.

While the Navy has not ruled out traditional steel hull concepts for LCS, the power to speed and weight ratios associated with the costly steels used for modern warship development may not offer acceptable solutions for the LCS fleet, Hamilton said.

Driven Away from Traditional Hull Types

"That has driven us away from building the traditional ship hull type," he said. "And it has forced many of the traditional shipbuilders to find other partners." The challenge of selecting the material and the hull form that provides the capability the Navy wants for LCS is a "multivariable equation," Hamilton added.

Balancing the factors of strength, weight, and cost in the context of hull form has presented complex challenges for the Navy and for the commercial sector. In addition to pursuing an advanced functional sea frame, NAVSEA has also raised expectations for affordable repair and life-cycle management costs.

These are among the requirements that prompted the competitors to generate leading-edge designs and concepts for the LCS or precursor technology demonstration programs. The initial contracts for LCS, expected to be awarded in july 2003, are limited to $10 million. The real inducement for shipbuilders is the potential to build a class of up to 65 such vessels.

GD's Bath Iron Works and Electric Boat Corporation head one LCS team that includes Austal, BAE Systems, and the British advanced concept development firm QinetiQ. Bath's team based its hull design for Focused Mission High-Speed Ship, a technology precursor to LCS, on an advanced trimaran hull form, GD vice president and LCS program manager Jim Baskerville told Sea Power.

"The strength of the General Dynamics-led LCS team is built upon the selection of an advanced trimaran hull form that is affordable, low risk, and flexible," Baskerville said.

One Team Proposes a 'Sea Blade' Concept

Lockheed Martin recently created a new partnership for LCS including Bollinger Shipyards, Gibbs & Cox, and Manitowoc Corporation's Marinette Marine. In addition, Lockheed Martin already had partnered with Germany's Blohm Voss for LCS and other programs, setting the tone for what Lockheed Martin program manager Carol Hulgus said could be further international partnerships.

"In addition to the principal team members, core team support includes high-speed ship expertise from Donald L. Blount and Associates, FastShip, Fincantieri, and NAVATEK; modularity expertise from Blohm Voss; functional expertise from Angle Inc., ABS, BBN Technologies, Char ters Technical Services, DRS Technologies, and Micro Analysis and Design," Lockheed Martin spokesman Kenneth Ross told Sea Power.