Harpax

"grabber, seizer, robber"; GEN ἅρπαγος harpagos)[1] was a Roman catapult-shot grapnel created by Marcus Vipsanius Agrippa for use against Sextus Pompey during the naval battles of the Sicilian revolt.

[2] The harpax allowed an enemy vessel to be harpooned and then winched alongside for boarding.

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.

"[3][4] The harpax had a distinct advantage over the traditional naval boarding device, the corvus, in that it was much lighter.