Except in the combat near Korkyra, and there only partially, the Peloponnesians had never yet made actual trial of Athenian maritime efficiency, at the point of excellence which it had now reached: themselves retaining the old unimproved mode of fighting and of working ships at sea, they had no practical idea of the degree to which it had been superseded by Athenian training. Among the Athenians, on the contrary, not only the seamen generally had a confirmed feeling of their own superiority,—but Phormio especially, the ablest of all their captains, always familiarized his men with the conviction, that no Peloponnesian fleet, be its number ever so great, could possibly contend against them with success.[338] Accordingly, the Corinthian admirals, Machaon and his two colleagues, were surprised to observe that Phormio with his small Athenian squadron, instead of keeping safe in Naupaktus, was moving in parallel line with them and watching their progress until they should get out of the Corinthian gulf into the more open sea. Having advanced along the northern coast of Peloponnesus as far as Patræ in Achaia, they then altered their course, and bore to the northwest in order to cross over towards the Ætolian coast, in their way to Akarnania. In doing this, however, they perceived that Phormio was bearing down upon them from Chalkis and the mouth of the river Euenus, and they now discovered for the first time that he was going to attack them. Disconcerted by this incident, and not inclined for a naval combat in the wide and open sea, they altered their plan of passage, returned to the coast of Peloponnesus, and brought to for the night at some point near to Rhium, the narrowest breadth of the strait. Their bringing to was a mere feint intended to deceive Phormio, and induce him to go back for the night to his own coast: for, during the course of the night, they left their station, and tried to get across the breadth of the gulf, where it was near the strait, and comparatively narrow, before Phormio could come down upon them: and if the Athenian captain had really gone back to take night-station on his own coast, they would probably have got across to the Ætolian or northern coast without any molestation in the wide sea: but he watched their movements closely, kept the sea all night, and was thus enabled to attack them in mid-channel, even during the shorter passage near the strait, at the first dawn of morning.[339] On seeing his approach, the Corinthian admirals ranged their triremes in a circle with the prows outward, like the spokes of a wheel; the circle was made as large as it could be without leaving opportunity to the Athenian assailing ships to practise the manœuvre of the diekplus,[340] and the interior space was sufficient, not merely for the store-vessels, but also for five chosen triremes, who were kept as a reserve, to dart out when required through the intervals between the outer triremes.