The harpax allowed an enemy vessel to be harpooned and then winched alongside for boarding. It was first deployed at the Battle of Naulochus in 36 BC. Appian explains the device was "called the 'grip', a piece of wood, five cubits long bound with iron and having rings at the extremities. To one of these rings was attached the grip itself, an iron claw, to the other numerous ropes, which drew it by machine power after it had been thrown by a catapult and had seized the enemy's ships."