236 



SHIP. 



being trimmed forward, so as to keep full, ure struck 

 obliquely, and if the ship were again free to move 

 in any direction, would impel her in a course per- 

 pendicular to its surface; but the portion of this 

 force tending to drive the ship to leeward, being 

 again encountered by the lateral pressure, is almost 

 balanced; while, on the contrary, she freely obeys 

 the force tending to propel her forward. Lastly, 

 let us consider the situation of our ship when the 

 wind gets before the beam, so as to make an angle 

 of less than ninety degrees with the course. It is 

 evident that, if she still continue to advance, it 

 must be towards the wind : this seeming paradox 

 of a vessel approaching the wind by the very effort 

 of that wind to drive it away, will still appear clear 

 by the application of the same principles. To meet 

 the emergency, let us now suppose the yards braced 

 forward, until they make an angle of only thirty 

 degrees with the keel ; the wind, being thirty far- 

 ther aft, will make an angle of sixty with the keel. 

 In this position, the wind will strike obliquely on 

 the after side of the sails; and though the greater 

 part of the force passes off to leeward, there is still 

 a partial effort to drive the sails in a direction per- 

 pendicular to their surface. This effort subdivides 

 into two forces; one perpendicular to the keel, the 

 other in a line with it : the first is nearly overcome 

 by the lateral resistance ; the second, encountering 

 less, causes the ship to advance, with a velocity 

 proportioned to the smallness of the angle of inci- 

 dence, and the disadvantageous application of the 

 propelling power. 



From what has been here stated, it would seem 

 that, in theory, the situation of the wind most fa- 

 vourable to propelling a ship, is when it acts per- 

 pendicularly to the sails, and they in turn to the 

 keel ; that is, when dead aft. In gales of wind, this is 

 likewise true in practice ; but in moderate weather, 

 a ship will sail faster with the wind on the quarter, 

 or even abeam; for then the sails do not mask each 

 other, but all receive the wind without interruption. 

 On this account they more than make up the dis- 

 advantages of the unfavourable angle; of having 

 the sails transported to leeward, by reason of which 

 that side tends to advance faster than the other, to 

 the disordering of the steerage ; of the ship's heel- 

 ing, and receiving the wind obliquely in the verti- 

 cal direction; and, finally, of making her sail par- 

 tially on one side, instead of on an even keel, as 

 she is designed to do. On this account our sharp 

 schooners will sail nearly or quite as fast on a wind 

 as off it, the sea being smooth and wind light ; for 

 whilst all their sails act advantageously, by ap- 

 proaching the wind, they add to its force, instead 

 of diminishing it, as when running from it. In 

 square-rigged ships, bracing the yards correctly is 

 one of the nicest points of seamanship ; in general, 

 the nearer the yards approach to being perpendi- 

 cular to the keel, consistently with keeping the 

 sails full, the greater will be the velocity. 



But to return to our ship; It may chance that 

 the wind does not stop at the exact point which 

 would enable her, close-hauled, barely to go her 

 course, but even heads her off so far that she can 

 no longer approach it nearer than a right angle. It 

 is evident, now, that she is gaining nothing; but 

 since she can sail within sixty degrees of the wind, 

 by closing with it on the other side, she may ap- 

 proach within thirty degrees of the desired course. 

 Hence it becomes essential to change sides. There 

 are two ways of performing this evolution: the 

 first consist* in turning round towards the wind, 



and is called tacking ; the second in turning before 

 it, and is called vevriny. As the first requires the 

 ship to turn a much smaller segment of a circle, 

 and moreover maintains her head towards the de- 

 sired course, so that all her progress during the 

 evolution is gain, and finally, since it is performed 

 with greater ease and expedition, it is always pre- 

 ferred when practicable. To tack, the crew are all 

 stationed at the tacks, sheets, braces, and bowlines, 

 ready to change the position of the sails. The 

 ship being already close to the wind, the helm is 

 gradually eased down, so that the rudder may not 

 exert its full force until she begins to turn, nor act 

 suddenly to check the headway, so essential to the 

 success of the evolution; at the same time, the 

 head sheets are flown, so as to cause the sails be- 

 fore the centre of rotation to shake, and lose their 

 power of balancing the after ones. As the ship 

 approaches the wind, the spanker is drawn gradual- 

 ly from the lee side towards the centre, that it may 

 keep full, and, by its action so near the stern, con- 

 tinue promoting the rotation. As soon as the sails 

 reach the direction of the wind, and cease to draw, 

 the corners of the courses are drawn up, and the 

 tacks and sheets overhauled, ready to swing the 

 yards. After a while, the sails catch aback, and 

 the fore sails, soon masking the after ones, act 

 with a powerful lever to turn the bow. At length, 

 having come head to wind, without loss of head- 

 way, and the evolution being certain, the after 

 yards are swung round, ready to receive the wind 

 on the opposite side ; which operation is then more 

 easily performed, from the sails being becalmed by 

 the fore ones. Lastly, when the after sails are 

 filled by the wind, the head yards are also braced 

 round to receive its impulse, and the ship at once 

 recovers headway. Should she gather sternway 

 before the sails become full on the new tack, the 

 helm is shifted, that its action in a backward direc- 

 tion, instead of checking, may aid the rotation. 

 There may, however, be occasions in which it is 

 impossible to tack, either because the wind is not 

 of sufficient force, or else so strong as to render it 

 dangerous; then veering is resorted to. To veer, 

 we put the helm hard up, brail the spanker, and 

 shiver the after sails: in this situation the pressure 

 of the head sails, not being balanced by the after 

 ones, tends, in conjunction with the rudder, for- 

 cibly to turn the ship. As she falls off, the after 

 sails are still kept shivering until braced sharp on 

 the opposite tack ; when before the wind, the 

 spanker is set to aid the after yards and helm in 

 bringing her to ; the fore sails are then squared, and 

 gradually braced forward until the ship be by the 

 wind again. 



Thus easily is a ship manoeuvred in fine weather. 

 Not unfrequently, however, a gale comes to disturb 

 the peaceful course of the mariner, and call forth 

 all his exertions. Let us suppose that, whilst ou. 

 ship is contending against the head wind, the mis- 

 fortune is augmented by its gradual increase. 

 Shortening sail becomes necessary, and is deter- 

 mined by two leading considerations the stability 

 of the ship, and the strength of her masts : it is to 

 diminish the careening of the one, and avoid en- 

 dangering the other, that the surface spread to the 

 wind is reduced. In shortening sail, we always 

 begin with the highest and lightest sails, descend 

 ing gradually, and keeping pace, in an inverse ratio, 

 with the increase of wind. The sails do not, 

 however, come in uniformly in the direction of the 

 length ; but the after sails most rapidly ; because, 



