Ball, W. W. Rouse (Walter William Rouse), 1850-1925 · London, Macmillan · leaf 120
ess than the pressure of the wind behind the sail and normal to it, the resultant of the two will be a force behind the sail and normal to it which tends to drive the boat forwards. But as the velocity of the boat increases, a time will arrive when the pressure of the wind is only just able to… … In the accompanying figure, let BAR represent the keel of a boat, B being the bow, and let SAL represeat the sail. Suppose that the wind is blowing in the direction WA with a velocity u; and that this direction makes an angle @ with the keel, ze. angle WAR=6. Suppose that the sail is set sv as to…
