Originally built in 2001 to capture high-resolution sonar images of sea beds for oil and natural gas companies, such as the Exxon Mobil Corporation, Echo Ranger underwent testing for possible use by the military. Among its possible military uses are to stalk targets in enemy waters, patrol local harbors to detect national security threats, and scour ocean floors to detect environmental hazards. The submersible weighs more than five tons (4.5 metric tons), is 18.5abbr=offNaNabbr=off long and is able to descend to 10000abbr=offNaNabbr=off.