Ships were not worthy of the name warship until they were able to overcome the power of wind and tide to maneuver against the enemy. The originals were merely transport and bases for infantry to fight each other away from land, but they had no inherent power of their own. Quantum leaps arrived in the form of propulsion and armament improvements.
Propulsion improved by adding horsepower, or rather, manpower. A single bank of oars was adequate to move the ship, but not to move it with the power and precision needed for combat maneuvering. Additional banks of oars, with the rowers staggered on benches, added the needed power. This also allowed a larger payload to be carried, which resulted in the addition of crew served weapons, (ballistae and arrow throwers). The increased speed and maneuverability encouraged the mounting of rams for direct action against enemy ships.
The next advance in propulsion came when efficient sailing sets were designed. Sail didn't increase top speeds, but it increased endurance radically, and top speed no longer came in just short bursts. Ships were now able to range much further with smaller crews and carry heavier loads. They lost the ability to ram, because that would tend to collapse the masts, but they could carry heavier weapons and more men whose job was actually to fight.
Sailing rigs and ship design improved slowly enough that galleys, including rams, survived well into the 1700's, especially in Mediterranean navies. (This may also be an example of the 'conservatism' of the military.) But they were definitely being phased out. 'Modern' warships combined efficient sail rigs with a variety of cannon that could destroy an enemy from a distance. Ships became purposefully built to fulfill a variety of needs. With most cannon mounted to fire to the sides, the most common tactic became the 'line of battle' which applied the maximum firepower to one side or the other. This gave us the term 'ship of the line' and later, battleship. (ship of the battle line) This arrangement of the guns also meant that only the half that faced the enemy were in action at any one time, except for the rare instance where a battle degenerated into a free for all, with the line of battle scattered.
