helmsman, the kybernētēs, who was always an experienced seaman and was often the commander of the vessel. These experienced sailors were to be found on the upper levels of the triremes. Other officers were the bow lookout (prōreus or prōratēs), the boatswain (keleustēs), the quartermaster (pentēkontarchos), the shipwright (naupēgos), the piper (aulētēs) who gave the rowers' rhythm and two superintendents (toicharchoi), in charge of the rowers on each side of the ship. What constituted these sailors' experience was a combination of superior rowing skill (physical stamina and/or consistency in hitting with a full stroke) and previous battle experience. The sailors were likely in their thirties and forties. In addition, there were ten sailors handling the masts and the sails. Rowers In the ancient navies, crews were composed not of galley slaves but of free men. In the Athenian case in particular, service in ships was the integral part of the military service provided by the lower classes, the thētai, although metics and hired foreigners were also accepted. Although it has been argued that slaves formed part of the rowing crew in the Sicilian Expedition, a typical Athenian trireme crew during the Peloponnesian War consisted of 80 citizens, 60 metics and 60 foreign hands. Indeed, in the few emergency cases where slaves were used to crew ships, these were deliberately set free, usually before being employed. For instance, the tyrant Dionysius I of Syracuse once set all slaves of Syracuse free to man his galleys, employing thus freedmen, but otherwise relied on citizens and foreigners as oarsmen. In the Athenian navy, the crews enjoyed long practice in peacetime, becoming skilled professionals and ensuring Athens' supremacy in naval warfare. The rowers were divided according to their positions in the ship into thranitai, zygitai, and thalamitai. According to the excavated Naval Inventories, lists of ships' equipment compiled by the Athenian naval boards, there were: 62 thranitai in the top row (thranos means "deck"). They rowed through the parexeiresia, an outrigger which enabled the inclusion of the third row of oars without significant increase to the height and loss of stability of the ship. Greater demands were placed upon their strength and synchronization than on those of the other two rows. 54 zygitai in the middle row, named after the beams (zygoi) on which they sat. 54 thalamitai or thalamioi in the lowest row, (thalamos means "hold"). Their position was certainly the most uncomfortable,