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HISTORY OF MARINE ARCHITECTURE.

regard to the formation of the vessel, so that it shall become as subservient aspossible to the will and the guidance of those who navigate it. It is highly incum-bent that the bottom should be so formed, that it should, as a first principle, answerwith the greatest promptitude to the helm and to the will of the pilot. Pos-sessing this property in a consummate degree of perfection, it will stay,wear, incline to the larboard, or to the starboard, just as he shall think con-venient and proper. The action of the rudder, which is certainly one of themost material discoveries in aid of navigation, depends in great measure on theclearness of the vessel’s run, that is to say, on the after body being so tapered,that the fluid through which it is forced, either by the impulse of the wind,or by artificial means, shall have such a clear and unimpeded passage, thatthe inclination of it may act upon it with the greatest force, and produce the effectrequired in the government, or steerage of the vessel. Those nations which*from a peculiarity of construction, founded either on a local partiality for certainprinciples, or, in general, from necessity itself, have thought proper to deviate fromthis rule, have found it necessary to construct the rudders of their vessels muchbroader than would become necessary among a people less bigoted to absur-dity, or less dictated to by powers they are unable to resist. For instance: letABC represent the horizontal lines of the after body or stem part of a vessel, builtaccording to those principles which are thought most perfect. It will evidentlyappear to, and be admitted by, the sturdiest sceptic, that the water having a freepassage to the rudder marked D, the latter need not extend more than the proportiongiven in fig. i. The case becomes materially different, supposing EFGH torepresent the water-line of a vessel: it will then become necessary to elongatethe rudder of such a ship from I to K, ere it can have any effect at all on thefluid; or at least, if any, it will be extremely immaterial. It follows, there-fore, that the rudder must be elongated from I to L, ere it can possess the samepower of action with the rudder D, which is only one-sixth part of its length.The inconveniences unavoidably arising from an adherence to the latter fashion,have caused it to be materially exploded in most countries, and particularly amongthe.southern nations; whose vessels are under less necessity of navigating thosetempestuous seas, in which such peculiarity of form has been thought to contri-bute to the safety of the vessel.

Exclusive of those general principles in marine architecture, which tend tothe safety, the speed, or the good management of a vessel, there are Certain localfionsiderations which must set all established principles, for the general construc-tion