Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

36. The Syracusans, hearing of their approach, desired to have another trial of the fleet, and to¹ use the army which they had collected with the express purpose of bringing on an engagement before Demosthenes and Eurymedon arrived in Sicily. [2] Profiting by the experience which they had acquired in the last sea-fight, they devised several improvements in the construction of their vessels. They cut down and strengthened the prows, and also made the beams which proejected from them thicker; these latter they supported underneath with stays of timber extending from the beams to and through the sides of the ship a length of nine feet within and nine without, after the fashion in which the Corinthians had refitted their prows before they fought with the squadron from Naupactus. [3] For the Syracusans hoped thus to gain an advantage over the Athenian ships, which were not constructed to resist such improvements, but had their prows slender, because they were in the habit of rowing round an enemy and striking the side of his vessel instead of meeting him prow to prow. The plan would be the more effectual, because they were going to fight in the Great Harbour, where many ships would be crowded in a narrow space. They would charge full in face, and presenting their own massive and solid beaks would stave in the hollow and weak forepart of their enemies' ships²; [4] while the Athenians, confined as they were, would not be able to wheel round them or break their line before striking, to which manœuvres they mainly trusted—the want of room would make the one impossible, and the Syracusans themselves would do their best to prevent the other. [5] What had hitherto been considered a defect of skill on the part of their pilots, the practice of striking beak to beak, would now be a great advantage, to which they would have constant recourse; for the Athenians, when forced to back water, could only retire towards the land, which was too near, and of which but a small part, that is to say, their own encampment, was open to them. The Syracusans would be masters of the rest of the harbour, and, if the Athenians were hard pressed at any point, they would all be driven together into one small spot, where they would run foul of one another and fall into confusion. [6] (Which proved to be the case; for nothing was more disastrous to the Athenians in all these seafights than the impossibility of retreating, as the Syracusans could, to any part of the harbour.) Again, while they themselves had command of the outer sea and could charge from it and back water into it whenever they pleased, the Athenians would be unable to sail into the open and turn before striking³; besides, Plemmyrium was hostile to them, and the mouth of the harbour was narrow.