During the summer months, except for a little early morning mist, there were no fogs and visibility was usually crystal clear. The northerly winds broomed the atmosphere and produced that extraordinary clarity of Greek light which makes an object several miles distant as sharply defined as one a few cables away. In the spring and autumn months, when the Meltem were not blowing, the sea was often misted with calm and a haze which the Rhodians called calina would lie like a smoky varnish over the surface. The peaks of the islands where the Knights had their look-out points would rise up sharp above the haze, and from their viewpoints the watchmen could descry the masts and yards of merchantmen moving softly through the island channels. It was then that, alerted by a signal or a beacon fire, the waiting galley could dash forward unobserved and be at close quarters before the crew on her opponent’s deck had spotted the lean bows smoking out of the mist.

Like all Mediterranean seamen they did not have to bother with tidal problems for the rise and fall was negligible, being only a matter of inches. Currents, however, were another matter and the pilots, who in any case had been familiar with the sea around the island since they were boys, had to be expert in knowing what flow might be expected in the channels between the islands. A galley under oars might make four and a half knots at full speed and about seven with a fair wind, which meant that a current of anything over half a knot was something to be reckoned with. It was upon the application of his knowledge of the direction and speed of the currents that a good pilot might help the galley-master make a capture where, on the face of it, it would have seemed that a fleeing merchantman was destined to make its escape. Up north by the Dardanelles, where the Black Sea flows into the Aegean, there was a strong surface current running south-westerly, but this was beyond the operational area of the Rhodian galleys. The overall current which interested them most was the southerly one which, driven by the Meltem, drove steadily along the islands, headlands, and inlets of the sea. Since there is a clockwise current throughout the whole Mediterranean, varying in strength but almost always present, pilots had to take this into account when working off the mainland coast. The current swirls past the island of Cyprus, turns westerly when it meets the southern coast of Turkey, and then flows northerly. In summer the current induced by the Meltem might cancel out this current or might even override it, but at other seasons of the year the pilot would have to take it into account. Similarly between individual islands, depending upon from what direction the wind was blowing, purely local currents—sometimes flowing as fast as two knots—had to be reckoned with. It was upon the Rhodian expertise in pilotage, as well as upon the excellence of their galleys and the fighting qualities of the Knights and men-at-arms, that the Order of St John relied for its mastery of these narrow waters. Southerly gales, bringing with them thick overcast weather (although little met with in the sailing months) could negate all other currents and give a north-flowing current even as far as the Bosporus and the Dardanelles.

Around Rhodes itself the Meltem which govern all the conditions of the Aegean in summer, instead of blowing from north-west, turned towards the Asian mainland and blew hard from almost due west. This gave a good working wind under sail for running up to the northern islands like Cos and Leros or to Smyrna itself, while for cruising off the southern coastline of Anatolia, into the Bay of Anatalya, or running down to Cyprus the galleys had a fair wind from astern. In Rhodes the westerly was the prevailing wind. In midsummer it might alternate with cool northerlies but there were also times when a lowering sky over Asia would betoken the advent of the most unpleasant weather in the island—unpleasant only in the landsman’s sense, for the seaman could often make good use of it. This occurred when the air over the thousands of square miles of parched mainland blew in from the east, raising the temperature and the humidity and causing the citizens of Rhodes to close their shutters and lie down in sweaty darkness on their beds. At such times galleys or merchant ships at sea could find reasonable anchorage and a lee under the southeastern shores of the island. They could also use this summer wind to make off to the islands that lay to the west, Crete for example. Other things which the Rhodian pilots, shipmasters, and their seamen had to know about were those typical island squalls which boil up over the high limestone peaks of the Aegean. Strong winds, or gales from the north, would cause violent gusts to descend the slopes and valleys on the lee side of mountainous islands or headlands. The mariner unfamiliar with this sea, who might have hoped to find a peaceful shelter in such areas, would be hit with terrifying blasts of wind, quite sufficient to dismast his vessel.

Except at one point off Crete, where considerable depths are found, the Aegean is a comparatively shallow sea. This means that any strong winds will kick up a short and unpleasant breaking sea far more quickly than would occur in an ocean or a deep sea. Under these conditions the narrow galleys with their comparatively shallow draught would find it almost impossible to pursue a course with the swell on the beam. If there was sea room they could turn and run before the weather; if not then they must head into it, the oarsmen straining at the jumping oars to try to maintain the ship’s status quo.

It was upon the men who manned the heavy looms of the oars that the galley depended for its speed in approach and for the run-in that preceded the action of ramming and boarding. In the days prior to the advent of guns upon ships the ram was still the principal weapon of the war galley. It could be used in two ways: either for a direct beam-on attack with the object of shattering the opponent’s side, or for making a glancing blow right down the side of the enemy, shattering his oars and leaving him stationary and helpless.