Heavy Warship

Summary
The Heavy Warship is an advanced warship, available to all faction groups except the Greeks. It is the heaviest ship type available to the Illyrians and Gauls, the latter of which have the hidden benefit of being able to construct them earlier on without requiring the Polyreme Ship Construction skill.

"Large quinquiremes with lots of oars, boosting their speed. These ships are designed for ramming and boarding other ships. Warships can carry one unit plus a supply of food."

- In-game Description

History
The quinquereme, a ship with 5 files of oarsmen on each side of the ship, was first developed around 400 BC in Syrakousai during the reign of Dionysios I, for his wars againt Carthage.

Initially, these quinqueremes served as flagships or command vessels in fleets mostly composed of the smaller triremes and quadriremes. Later on however, such as during the Punic Wars between Rome and Carthage, quinqueremes had become the most common type of warship with the lighter triremes being relegated to a more minor role and even larger polyremes being used as command vessels.

Note that the number in the ship's name did not refer to the amount of oars, but rather the amount of rowers. For practical reasons, it is unlikely that the quinquereme had 5 rows of oars. Rather, they likely had 3 rows of oars similar to triremes, but with 2 of those rows consisting of longer, more powerful oars that were manned by 2 oarsmen.

Unlike the other heavy warships, the Gauls use a different model which does not represent a quinquereme but rather an oaken sailing ship without oars, similar to the Gallic/Illyric Light Warship but larger.

Tactics
Heavy Warships are superior in ramming and boarding to Light Warships, but somewhat slower to move. If the player can afford it, they may want to entirely replace their Light Warships with Heavy Warships eventually.

They also have a significantly improved missile damage output to make them much more viable for very short-range missile support to other warships. Late-game Flagships (for those factions that have access to them) are much superior in the missile department though, and will relegate Heavy Warships to a melee-only role.