Page:The American Boy's Handy Book edition 1.djvu/154

right direction, place a light weight on her bow, so that she will be a little 'down by the head,' or move the aftermost mast and sail a little nearer to the stern.

"The little rude affair thus used for experiment will not actually make any progress to windward, because she is so light that she moves sidewise almost as easily as she does forward. With a larger, deeper boat, and with sails which can be set at any angle, the effect will be different. So long as the wind presses against the after side of the sail, the boat will move through the water in the direction of the least resistance, which is forward. A square sail, having the mast in the middle, was easiest to begin with for purposes of explanation; but now we will change to a 'fore-and-aft' rig—that is, one with the mast at the forward edge or 'luff' of the sail, as in Fig. 91. Image missingFig. 91. Suppose the sail to be set at the angle shown, and the wind blowing as the arrow points. The boat cannot readily move sidewise, because of the broadside resistance; she does not move backward, because the wind is pressing on the aftermost side of the sail. So she So she very naturally moves forward. When she nears buoy No. 1, the helmsman moves the 'tiller,' or handle of the rudder, toward the sail. This causes the boat to turn her head toward buoy No. 2, the sail swings across to the other side of the boat and fills on that side, which now in turn becomes the aftermost, and she moves toward buoy No. 2 nearly at right angles to her former course. Thus, through a series of zig-zags, the wind is made to work against itself. This operation is called 'tacking,' or