TORPEDO BOAT. 359 TORPEDO BOAT. teries, steam motors, oil motors, and oil give off fases which are not only annoying and injurious, ut may prove dangerous. It may be possible to reduce troubles of this sort to satisfactorj' limits by inclosing the machinery in air-tight casings, but in the handling and inspection some gas is sure to escape. There can be no cooking, no proper sleeping accommodations, no proper water- closets, and the natural light is feeble. The mo- tion is as trying as it is on a surface boat. A short consideration of these tilings is suflicient to show that the ease of securing fair habitability increases with the size of the boat, to which of course there is a limit. The conditions affecting the stability of an en- tirely submerged vessel dift'er considerably from those affecting the stability of one floating on the surface. (See Shipbuilding.) Since the sectional area of the immersed body remains un- changed at all angles of heel, the position of the centre of buoyancy is constant ; the righting mo- ment therefore grows more slowly as the boat heels. By suitable ballasting or arrangement of weights adequate transverse stability is not very dinicult to attain. But longitudinal stability is quite another matter. Any possible assistance from ballasting or the arrangement of permanent weiglits is insignificant, and the cliange of trim due to the using of fuel and shifting of weights (torpedoes, men, liquid in partly filled tanks, etc.) is a very serious matter. It is counteracted by the use of horizontal rudders, or shape of the hull, or quickly shifting water-ballast. If the boat has a slight surplus buoyancy the tendency to rise to the surface can be counteracted by vanes or the shape of the head which tends to make the boat descend so long as it is moving. But as the effect of hull shape or permanent vanes changes with the speed, while the buoyancy eiTort is constant, horizontal rudders are a neces- sity. From these facts it follows that short, deep, and broad boats are mast stable, but such a shape is incompatible with speed. The difficulties experienced in dis- charging torpedoes are closely connected with the question of stability. In ad- dition to confined space in which tor- pedoes are operated, and the difficulty of giving them the correct direction at the moment of firing, it is necessary that the boat should be nearly hori- zontal when the torpedo is fired, else the latter will take too deep a dive or rise to the surface at the beginning of its run. The shock of firing and the sudden release of weight at the bow as the torpedo leaves it causes gi'cat longi- tudinal disturbance in the boat, and may bring it to the surface, while the change in permanent trim adds to the difficulty of maintaining a constant depth. The submarine torpedo boat as de- veloped in 1903 was certainly far from a perfect weapon, being of little use except in smooth water, difficult to use at night, and having a very short radius of action. But. imder favorable circumstances, it was thought that it miglit achieve a great suc- cess, while the knowledge of tlie presence of submarines in a port cannot but have a powerful effect upon the nerves of the officers ami crews of blockading vessels. When or by whom was built the first sub- marine boat will probably never be known. It is said that Alexander the Great was interested in submarine navigation, while subaqueous at- tack of vessels was studied at least as early as TORPEDO SCREW. VENTILATORS^ VERTICAL PROPELLER BALLAST TANK BALLAST.N DETACHABLE BALLAST AND ANCHOR TLOODING VAWE .PUMP BALLAST TANK urSHNELL's BOAT (1775). the thirteenth or fourteenth century. M. Del- peuch states that some English ships were de- stroyed in 1372 by fire carried under water. In the early part of the seventeenth century sub- marine boats were numerous, and in 1024 Corne- lius Drcbbel exhibited to King James I. on the Thames a submarine boat of his own design. By 1727 no less than 14 types of submarines had been patented in England alone. In 1774 Day began experiments with a submarine boat at Plymouth, England, losing his life in the second submergence trial. In the following year David Bushnell built his first boat, with which Sergeant MAST AND SAIL, [l TORPEDO SPIKE CONNING TOWER, TORPEDO GEAR f WATER TIGHT BULKHEAD -iL- ANCHOR VMAST GEAR |/PROPELLER ™aj>S— .HORIZONTAL •^*^t=^^^— -RUDDER _i '■•rrTr'i ■f=UMPS ■■ RUDDER HOLLOW' IRON KEEL FULTON'S NAUTILra (1801). Lee attacked H. M. S. Eagle in New York Har- bor. Lee actually got under the ship, and the attack failed only because the screw by which the torpedo was to be attached to the Eagle's bottom was not sharp enough. Robert
