The famed boarding bridge, known to us as the corvus, should be explained in some detail. Fortunately for us Polybius has left a solid whole chapter description of the corvus in his surviving work. I’ll let him speak for himself.
After this the Romans approached to coast of Sicily and learning of the disaster that had befallen Gnaeus, at once communicated with Gaius Duilius, the commander of the land forces, and awaited his arrival. At the same time, hearing that the enemy’s fleet was not far distant, they began to get ready for sea-battle. As their ships were ill-built and slow in their movements, someone suggested to them as a help in fighting the engines which afterwards came to be called “ravens.” They were constructed as follows: On the prow stood a round pole four fathoms in height and three palms in diameter. This pole had a pulley at the summit and round it was put a gangway made of cross planks attached by nails, four feet in width and six fathoms in length. In this gangway was an oblong hole, and it went round the pole at a distance of two fathoms from its near end. The gangway also had a railing on each of its long sides as high as a man’s knee. At its extremity was fastened an iron object like a pestle pointed at one end and with a ring at the other end, so that the whole looked like the machine for pounding corn. To this ring was attached a rope with which, when the ship charged an enemy, they raised the ravens by means of the pulley on the pole and let them down on the enemy’s deck, sometimes from the prow and sometimes bringing them round when the ships collided broadsides. Once the ravens were fixed in the planks of the enemy’s deck and grappled the ships together, if they were broadside on, they boarded from all directions but if they charged with the prow, they attacked by passing over the gangway of the raven itself two abreast. The leading pair protected the front by holding up their shields, and those who followed secured the two flanks by resting the rims of their shields on the top of the railing. Having, then, adopted this device, they awaited an opportunity for going into action.(Polybius 1.22)1
All in all, the corvus was a fairly simple, but effective, contraption. Some later ancient sources interpreted the Roman boarding successes as simply using specially formed grappling irons. While this may also be true, it makes no sense for Polybius to devote this much space and very specific description to something that actually did not exist. Generally, I stick with Polybius unless there is very good reason to do so. Also, various depictions of the mechanical setup of the corvus have been debated. An older theory was that the shorter length (two fathom section) was always flat on the deck of the ship and connected to the longer bridge portion by way of a hinge. However, Polybius makes no mention of a hinge in his description. The most literal interpretation is that the entire bridge of six fathoms, roughly somewhere on the order of thirty-six feet, was one solid piece. This is why the hole is oblong on the shorter end as a slot for the pole when the long part is drawn up by the pulley. The bridge couldn’t be pulled up directly parallel with the pole, but the weight of the bridge with a iron spike pointing downwards on the bottom of the end of the bridge would be sufficient to break through an enemy ship, holding it fast. This iron spike is where the name of the corvus seems to come from as it looked like the large beak of raven.
The Romans decided to make sea battles more like land battles with this technology to compensate for their lack of naval experience. In this capacity, the corvi appear to have worked exceptionally well. As we saw in the Battle of Mylae, the first onrush of Carthaginian attackers were all caught and held in place by the corvi. However, Polybius may be being a little loose with his information when he states that despite the Carthaginains’ speed and maneuverability during flanking tactics, “the ravens swung round and plunged down in all directions and in all manner of ways so that those who approached them were of necessity grappled.” (1.23)2 This is because a corvus setup on the foredeck of a ship would not be able to reach enemy ships approaching from the stern. Despite this, the Romans appear to have adopted some sort of means of protecting each other’s ships in this weak spot as the Carthaginians could not make much headway against them.
While the corvus proved its worth at Mylae (a full account of the battle can be found here) and would continue to be used in upcoming battles, it was not to last the entire duration of the war. For reasons that are not totally clear, use of the corvus seems to have been dropped as the war continued on. Carthaginian innovators may have started coming up with counter tactics to negate the corvus. Also, as we shall see, the corvus may have made quinqueremes even more unsteady on the high seas than they already were. This would prove disastrous in the seasons to come.
- Polybius. The Histories. Translated by W. R. Paton. 1922.