In classical antiquity, a ship's main weapon was the ram ("rostra", hence the name "navis rostrata" for a warship), which was used to sink or immobilize an enemy ship by holing its hull. Its use, however, required a skilled and experienced crew and a fast and agile ship like a trireme or quinquereme. In the Hellenistic period, the larger navies came instead to rely on greater vessels. This had several advantages: the heavier and sturdier construction lessened the effects of ramming, and the greater space and stability of the vessels allowed the transport not only of more marines, but also the placement of deck-mounted ballistae and catapults.