05 Feb 2018 |Kyle Mizokami | Popular Mechanics
“The U.S. Navy accepted delivery of a revolutionary uncrewed surface ship, one capable of traveling long distances and conducting missions all without a human on board. The Sea Hunter Anti-Submarine Warfare Continuous Trail Unmanned Vessel—or ACTUV for short—could someday lead to fleets of unmanned warships plying the world’s oceans, doing everything from hunting submarines to acting as spy ships.
The U.S. Navy ordered the ACTUV in 2012 as part of the Pentagon’s broader push into unmanned air, sea, and land systems. It was envisioned as a platform to test the autonomous concept in surface ships, explore how to safely and securely operate unmanned ships for months at a time over thousands of nautical miles, and create a vessel capable of tracking enemy diesel-electric submarines.
Built at the Christensen Shipyards in Vancouver, Washington, the 132 foot long, 140 ton ship is the world’s largest uncrewed ship. The pilothouse, necessary for a human crew to control the ship, can be unbolted and removed. The ACTUV has a single hull with two outrigger floats to enhance stability at sea, and has a maximum reported speed of 27 knots. From above the ship looks like a Romulan Bird of Prey, its hull and two floats slicing through the water, leaving three wakes.
An autonomous ship like the ACTUV would make an excellent submarine hunter. Conventionally-powered submarines, which make up the bulk of the world’s submarine fleets, can stay underwater for up to two weeks at a time. That’s longer than a helicopter or fixed-wing aircraft can stay on station, and a crewed surface ship puts the hunter at risk of becoming the hunted. An uncrewed ship, however, can track an enemy submarine as long as it takes for the sub to make a fatal mistake, then attack with a lightweight homing torpedo.
The ACTUV went to sea in October 2016, and spent 2017 undergoing a series of progressively more difficult tests at sea. Along the way, DARPA realized some important things. For one, the ship was also useful for launching the TALON elevated sensor mast. TALON is basically a militarized parasail towed behind a ship, lifting a 150 pound payload up to 1,500 feet above sea level. Possible payloads for TALON include communications relays in situations where satellite-based communications are unavailable and so-called “intelligence, surveillance, and reconnaissance (ISR) sensor packages.
Along the way, DARPA has expanded the potential roles for the ACTUV. No longer just an anti-submarine warfare platform, in 2016 DARPA was referring to the ship as a “payload truck” and the name was changed to Sea Hunter. TALON aside, the possibilities for an uncrewed surface ship are pretty much endless. Uncrewed ships could shoot it out with swarms of Iranian speedboats in the Straits of Hormuz, lay in ambush for a Chinese Navy surface task force, brimming with anti-ship missiles hidden under a stealthy exterior, or sail up and down the North Korean coastline, scooping up radio signals with a spy package hovering a third of a mile above it on TALON, all without exposing a single friendly sailor to danger. Uncrewed ships could even conduct resupply runs in dangerous waters, bring fresh missiles, torpedoes, and other supplies to ships at sea while sending injured sailors back to the rear.
Ships like Sea Hunter are also the future because they have to be. The U.S. Navy has only a limited number of crewed hulls to handle missions at hand, and the personnel costs involved in crewing those ships are a major part of the Navy’s budget. Small uncrewed ships offer a clever, cost-effective alternative. Sea Hunter doesn’t have an engineering section, or ship’s mess section, or anyone else whose role is to keep the ship and crew running. Sea Hunter’s autonomous nature means that a land-based crew need only man the ship’s sensors and weapons, when the ship is in action. A single crew could likely operate multiple Sea Hunters, only “crewing” them when the ship is in action.
Sea Hunter will operate under the Navy’s Office of Naval Research, where it will “develop (Sea Hunter) technologies, including automating payload and sensor data processing, rapidly developing new mission-specific autonomous behaviors, and exploring autonomous coordination among multiple (Unmanned Surface Vehicles)”. After that, likely some time in 2018, Sea Hunter will move on to become part of the broader U.S. Navy and could be assigned to actual real-world missions.