The power harpoon launcher, often called a harpoon and tow cable, was originally an industrial towing device. The Alliance modified it into a weapon.
Ubrikkian manufactured the power harpoon launcher. It included a magnetic accelerator, spools of high-tension cable, and several fusion disks. Typically, it was mounted at the rear of a vehicle. A swivel mount allowed some aiming flexibility. An electronic sight, which could connect to a standard targeting computer, aided in targeting.
The launcher's magnetic accelerator propelled a fusion disk attached to a tow cable. This disk could attach to any metal surface, creating a secure connection. After the disk attached, the cable was tightened and locked. Its maximum range was two hundred meters, but the best range was only one hundred meters. The launcher could hold three spools of cable, each two hundred meters long, and three fusion disks.
Some versions had a fusioncutter to sever the tow cable. The cable could then drift freely, or another fusion disk could be attached. This allowed linking multiple barges or skiffs, or transferring cargo between vehicles.
Ubrikkian Transports produced the Mo/Dk power harpoon, which was commonly used on snowspeeders modified by Alliance technicians.
Power harpoons and tow cables were used throughout the galaxy for towing cargo. They were attached to tugs and airspeeders and connected to loaded cargo skiffs. Because the skiffs were towed, their repulsorlifts could focus on lifting, allowing them to carry more cargo.
Alliance to Restore the Republic tactician Beryl Chiffonage, working with Commander Luke Skywalker, developed an offensive use for the power harpoon to fight All Terrain Armored Transports. This tactic was heavily used during the Battle of Hoth.
The gunner on a snowspeeder operated the harpoon. The fusion disk-tipped harpoon was fired at the leg of an Imperial AT-AT walker. The pilot then circled the walker several times, wrapping the flexisteel cable around its legs. The walker became trapped and fell, effectively disabled. Harpoons and tow cables brought down several AT-ATs at Hoth, making them the Alliance's best defense against the deadly Imperial walkers.
In addition to the harpoons and tow cables, some weapons, like the tow-cable bomb, were designed specifically for power harpoons.
The Galactic Empire used it as a boarding weapon. Assault shuttles used it to immobilize starships before Zero-G assault stormtroopers boarded.