However, the ships at Peiræus, if not large in size, are numerous enough. Some are simply big open boats with details elaborated. They have a small forecastle and poop built over, but the cargo in the hold is exposed to all wind and weather. The propulsion comes from a single unwieldy square sail swinging on a long yard the whole length of the vessel. Other ships are more completely decked, and depend on two square sails in the place of one. A few, however, are real “deep sea” vessels—completely decked, with two or even three masts; with cabins of tolerable size, and forward and aft curious projections, like turrets,—the use whereof is by no means obvious, but we soon gather that pirates still abound on the distant seas, and that these turrets are useful when it comes to repelling boarders. The very biggest of these craft run up to 250 gross tons (later day register),[*] although with these ponderous defense-works they seem considerably larger. The average of the ships, however, will reckon only 30 to 40 tons or even smaller. It is really a mistake, any garrulous sailor will tell us, to build merchant ships much bigger. It is impossible to make sailing vessels of the Greek model and rig sail very close to the wind; and in every contrary breeze or calm, recourse must be had to the huge oars piled up along the gunwales. Obviously it is weary work propelling a large ship with oars unless you have a huge and expensive crew,—far better then to keep to the smaller vessels. [*] The Greeks reckoned their ships by their capacity in talents (= about 60 lbs.), _e.g._ a ship of 500 talents, of 2000, or (among the largest) 10,000.