During the battle of Marathon, while the Persians retreated, Cynaegirus—brother of Aeschylus—is said to have grabbed the prow of one of their ships with one bare hand. This prevented the ship from launching.
How does that work? Wouldn’t there have been a half dozen Persians pushing it out into the water?
Ancient historians are prone to hyperbole from time to time, but the hyperbole had to be believable. That must have made sense to people at the time. Can anyone explain it?
This prevented the ship from launching.
Nobody says that. Cynaegirus' death comes to us from Herodotus 6.114:
τοῦτο δὲ Κυνέγειρος ὁ Εὐφορίωνος ἐνθαῦτα ἐπιλαμβανόμενος τῶν ἀφλάστων νεός, τὴν χεῖρα ἀποκοπεὶς πελέκεϊ πίπτει
Cynaegirus the son of Euphorion fell there, cut off at the hand by an ax while he was grabbing onto the stern of a ship.
That's all Herodotus says about it. In a few later places we're told that Cynaegirus was monumentalized at Athens, but there's nothing about stopping the ship from launching. Justin, a thousand years later, expands the story with a description of Cynaegirus' unstoppable bloodlust, where he grabs onto the ship with his other hand and then, when that too is cut off, his teeth. The story is clearly Justin's fantasy. The Suda also mentions Cynaegirus. Ancient commentators never commented on the passage, although the term ἄφλαστον is the subject of kind of a stupid debate between some of the epic commentators and scholiasts regarding whether that part of the ship is particularly strong or weak. Likely the point of what Herodotus is saying is that either Cynaegirus was trying to break off the decorated prow as a trophy, or he was trying to board the ship. It doesn't really matter which: nobody says anything about stopping the ship.