Naval tactics consisted of two main methods: Ramming required a small, fast ship. Boarding required larger ships with large numbers of boarders, and this school eventually prevailed because ramming required making contact, which is what the boarders wanted. Boarding ships had grappling hooks, boarding planks, and catapults, including the harpax or catapult-mounted grapnel.

Ramming used two tactics. The periplus was simple, where the line of battle was extended horizontally until the enemy was outflanked and his sides could be rammed. The diekplus was more complex, requiring a well trained crew of fast ships, but could be more effective if the enemy consisted of larger warships. The attacking fleet would form in line ahead, bow to stern, and row towards the center of the enemy's battle line. The attacking flagship (in the lead) would back oars on one side and use its momentum to sheer off the oars of one of the enemy ships, crippling it. The flagship moves on while the second in the attacking row finishes off the crippled ship. Any defending ships that move to intercept would be exposing their own sides to an attack.

The counter to a diekplus is to form in two lines, rendering the attack suicidal – but by shortening the line this way, one becomes vulnerable to a periplus. The other essentially defensive maneuver was the kyklos or defensive circle. The defending fleet formed a circle, rams pointing out. Inside the circle could be a smaller circle (say, 5 ships) to serve as a second line against a diekplus attack. This was used by outnumbered or slower fleets (the Greeks used it against the Persians at Artemesium, and it was used by the Peloponnesians against the Athenians off Rhium in 429 BC).

As indicated in the explanation of the diekplus a ramming attack had two variations. A direct ramming attack required an oblique angle, and it made the attacker vulnerable to a boarding action, but it did not require any great skill on the part of the rowers. The other variant involved the attacking warship brushing against the enemy to break their oars on one side, which would also cripple or kill the rowers. It was safer for the attacker because while the attacker was still at risk of a grappling hook, archers and artillery, it was a fast attack that kept some distance as there was no real contact between the ships. The attacker needed skilled rowers, however, because the rowers had to be able to raise up their oars all at once, at the right time – or the attacker would cripple themselves too!

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*Note: This and the previous post are based on John Warry's Warfare in the Classical World, ©1980 Salamander Books Ltd., London.