Sea Hunter

Lore & Background

Sea Hunter was christened on 7 April 2016 in Portland, Oregon, as the first vessel of the DARPA ACTUV program. Designed and built by Leidos, with manufacturing subcontracted to Christensen Shipyards and later Vigor Industrial after Christensen entered receivership, the ship continues a line of experimental 'Sea' vessels including Sea Shadow, Sea Fighter, Sea Jet, and Sea Slice. It is classified as a Class III USV and designated the Medium Displacement Unmanned Surface Vehicle (MDUSV). The initially unarmed prototype weighs 135 tons, including 40 tons of fuel, and is powered by two diesel engines driving twin screws. Its trimaran hull provides stability without a weighted keel, allowing better shallow-water operations, though the greater width reduces maneuverability. A removable operator control station was installed during testing for safety and backup; operationally, the ship uses Sparse Supervisory Control, where a human observes and can take charge but does not directly pilot the vessel. The system navigates using optical guidance and radar to avoid obstacles. Following successful initial development, DARPA handed Sea Hunter to the Office of Naval Research (ONR) in February 2018.

Reader's Guide

Sea Hunter's significance lies in its demonstration of long-endurance, unmanned surface operations at a fraction of the cost of crewed warships—$15,000–20,000 per day versus $700,000 per day for a destroyer. Its successful initial trials in June 2016 met or surpassed objectives for speed, maneuverability, stability, seakeeping, and fuel consumption. The vessel underwent testing with ONR starting in summer 2017 for mine-countermeasure, EO/IR, and submarine detection capabilities, with plans for ISR and offensive anti-submarine payloads by FY 2018. In August 2022, Sea Hunter participated in RIMPAC alongside other unmanned vessels. By 2026, Sea Hunter and a sister ship, both of Surface Development Group One, were to be operationally deployed as the first division of USVs. The People's Republic of China was reported in 2020 and confirmed in 2024 to be building clones of Sea Hunter. A sister ship, USV Seahawk, was built in 2021. The craft's legacy includes proving the viability of unmanned surface vessels for anti-submarine and counter-mine roles, with potential future armed variants requiring human approval for lethal force.

Did You Know?

• Sea Hunter can travel from San Diego to Guam and back to Pearl Harbor on a single tank of fuel.
• The ship is designed to be operational through Sea State 5 and survivable through Sea State 7.
• Deputy U.S. Defense Secretary Robert Work stated that if weapons are added, a human would always remotely decide to use lethal force.
• China was reported building clones of Sea Hunter, with confirmation in 2024.