Penn State ARL delivered SEAHORSE 1 to NAVOCEANO in October 2000. It executed its first operational survey from USNS Bruce C. Heezen (T-AGS-64) a year later. The vehicle is presently equipped with a 150-kHz sidescan sonar, a 300-kHz acoustic Doppler current profiler, a mast-mounted global positioning system antenna, and an inertial navigation system. SEAHORSE 2 was delivered in October 2001 and is currently in underway testing. Penn State is also fabricating a third operational vehicle, SEAHORSE 3.
SEAHORSE construction is modular to facilitate field maintenance, rapid mission turnaround, and payload flexibility. With an integrated afterbody for propulsion and hydrodynamic control, plus variable ballast systems fore and aft, the UUV can execute a variety of high-level commands, such as maintaining a constant depth, course, and speed; navigating between waypoints; and conducting search and survey patterns. Typical mission operating depths range from 15 to 1,000 feet, with endurance up to 72 hours. SEAHORSE vehicles are 28 feet long, slightly more than three feet in diameter, and weigh 10,500 pounds. Standard alkaline batteries (D-cells) power the vehicle, allowing a 300-mile range. NAVOCEANO plans to transition to rechargeable lithium-ion battery technology in the near future.