A two-decker with her bowspirit and masts out and her deck-planking removed to show the construction.

      When the wind was from behind and the sails were spread, obviously the ship was pushed forward – not that this was the best point of sailing, because if the breeze were right astern, the after sails would becalm the rest, whereas if it came from her quarter, or 45° abaft the beam, it would fill them all. But when the wind came from the beam, that is to say sideways, or at right-angles to the ship’s length, then the square sails would have been useless unless they could swing round to catch its force. And of course that is what happened: the yards were pulled round with braces and the lower corners of the sails were hauled round too – the sheet on the lower leeward corner was hauled aft and the tack, the rope on the windward lower corner, was hauled forward, so that the sail continued to draw; and seeing that the ship could not be forced sideways through the water it went on going forward, though a little sideways too – this sideways motion was called its leeway. Indeed, even when the wind was more from in front than sideways, the ship could still go on: a square-rigged ship, close-hauled, that is, with her yards braced up sharp to an angle of 20° with the keel, could sail within six points of the wind, or 63° 45' from it – or in other words, if the wind were coming from the north, she could still sail east-north-east.

      So much for the ships: now for the guns.

       The Guns

      The early guns had beautiful names like cannon-royal, cannon-serpentine, demi-culverin and falconet, but they had a bewildering variety of shot and charge; and since these weapons, together with basilisks, sakers and murdering-pieces might all be mounted on the same deck, it led to sad confusion in time of battle.

      By the eighteenth century there were many fewer kinds, and they were called by the weight of the shot they fired: a first-rate, for example, carried 30 32-pounders on her lower deck, 28 24-pounders on her middle deck, 30 18-pounders on her upper deck, 10 12-pounders on her quarterdeck and 2 on her forecastle, thus firing a broadside of 1,158 lb. Everything was plain and straightforward: each deck had guns, shot, cartridges and wads of the same size; the guns could be supplied from the magazines as fast as the powder-boys could run; and all that remained was to fire them as quickly and accurately as possible.