The U.S. Navy uses colors to describe where a ship is built to operate: Brown for rivers, blue for oceans and, recently, green for coastal, or littoral, waters. The Navy, traditionally focused on dominating oceans, does not have a vessel built to operate in green waters, so it is seeking a fast, shallow-keeled ship that can chase down enemies and dispatch helicopters with ease. In 2002, the Navy solicited builders to design its Littoral Combat Ship. Australia-based Austal recently launched its contender, the 417-ft. Independence. Its trimaran hull provides a stable ride at high speeds and in rough waves. The vessel is one of two the Navy is considering for the LCS–Lockheed Martin has already launched its monohull prototype, Freedom, and recently powered the ship’s electrical systems. Both programs are over budget and behind schedule, but a winner may be announced by year’s end.RELATED STORIES• PLUS: 3 New Ways Navy Will Fight Underwater Terrorism• TECH WATCH: Lockheed’s Radar Tech Could Shift Sea Power• EARLIER: Robot Boats Hunt High-Tech Pirates at SeaAustal’s Independence (left) and Lockheed Martin’s Freedom (right) are battling for a U.S. Navy contract.