The ancient ships were surprisingly sophisticated. Ask a nautical designer, engineer, and then spout crap.
The Kyrenia ship was built in Greece, how do you think it got to Kyrenia where it was sunk by pirates? And how did these pirates pursue it and attack it if not by other ships?
Kalymnian sponge divers worked off the coast of Paphos, arriving there with their boats, the most usual type being around 10 or 12 meters. Visit the sponge museum in Paphos, look at the photos. The Kalymnian trehantiri, (no GPS) is a lot smaller than ancient trading ships.
You are a typical land lubber, stick to donkeys. Ships are complicated things.