Arming Roman galleys with seventeenth-century cannon

Which seventeenth-century guns would suit Roman ships during the Second Punic War?

Light three-pounders would give useful antipersonnel fire, with perhaps one forward twelve-pounder if the hull could absorb it.

Light antipersonnel cannon would exploit the exposure of an opposing galley's oarsmen. Three-pounders offer a way to carry several useful guns on a lightly built ship. Quadriremes receive a qualification because their bows were strongly built to support the ram. The reinforced bow could make a single forward twelve-pounder possible, although carrying it remains uncertain. A parallel example puts a Renault FT17 or British light tank on a nineteenth-century battlefield, where its machine-gun fire would already provide the needed advantage. The Napoleonic comparison therefore has little use for a modern 120 mm tank gun. Both examples favour a light weapon that achieves the required effect without the weight of a much larger gun.