The Corvus is a hook like device used to attach a ship to an enemy ship. It was a combined grappling device and gangway, basically a narrow bridge of 18 feet in length. It was invented by the Romans during the Punic Wars and first used in the Battle of Mylae in 260 B.C. to great success. Unlike other inventions that have popped up throughout history, the Romans waited until they had them in sufficient number to totally surprise their enemy.
For the Romans the invention made them a threat at sea for the first time. Rome's strength was always with its land fighting and the skill of its soldiers. This helped to bring that same skill to bear when on the water. But the corvus was not used except during this particular historical period.
- Encyclopedia of Military History, Dupuy & Dupuy, 1979