Southern shield., 1852-05-01
From the National Intelligencer.
Naval.

Naval
 In no department of the arts anC sciences has this go-ahead age made more striking progress than in the models of sea. lgoing ships for sail or steam, or both pur. lposes combined.
 Our merchant vessels, both sail and lsteam, have steadily improved upon the an cient models, and it may be said, and truly, that the dullest sailer of the modern build is Iqute equal to the fastest ship afoat at the beginning of the century
 Fifty years ago little more than thrice the breadth of the beam was considered the best length which could be given to ves- sel; and the main breadth was carried as far forward as they could get it consistently with the spherical form of bows, which was then deemed esential to quick and easy mo- lion through the water; whilst at the pres ent day the main breadth is placed nearly amidshiP, and the bow sharpened to the wedge-like form.
 It was then argued that the bottom of ship should be fashioned like the body of fish, which was seen to force its way with prodigious velocity big end foremost through thS "otCts uilu tilCiClOIS SlllpS were UulIL accordingly up to recent day.
 It was maxim, and is now amongst the anciont salts, that spar, or any other float ing or submerged body, should be lowed or moved big end formost to overcome the resistance of the water; and so our ships, public as well as private, were constructed like the frustrum of a cone, 10 be driven through the water butt-end foremost.
 Precisely the reverse of this assumed is true in fact, and ships are now fashioned to penetrate water, as we shape all other mechanical appliances designed to penetrate any resisting medium, whether liquid, seni-lquid, or a solid, to wit: with as sharpa point or edge as the nature of the substance to be penetrated or divided will permit.
 And so at last we build sharp ships, which divide the liquid element, with the least re- Sistance; or in other words, move with ve- locity, all other things being equal, propor- tionate to their sharpness.
 In order to apply this fundamental prin- ciple to shipbuilding, resort to increased length is found to be imperative, and ships now have five and a half, six, and even sev- en times their main breadth of beam for length, instead of three, as formerly
 The effect of this change of model is quite remarkable. The passenger steamers have increase in speed from six and eight to fif- teen, eighteen knots an hour; and the mer- chant ships whose maximum rate of sailing thirty years ago was ten, have reached the astonishing velocity of eighteen knots.
 The clipper merchant hip"Flying Cloud" on the 30lh and 3lst July and lst August 1851, made, as per log, 2S4, 374, and 334 miles each day, respectively; or l,l49 stat ute miles in three consecutive days. Du- ring squal on the 3lst July eighteen knots of line were not sufficient to measure her rate of sc3;!'inc
 Three hundred and seventy-four sea miles, or four hundred and thirty statute miles, in one day, is the largest run ever made on the ocean, and beats the fastest sea steamer that has yet been put afoat. Now, if a sail ship can keep up this run for twenty four hours, a steamer may be lconstructed to keep it up eight days, and hence make the passage to Liverpool almost within the week. Undoubtedly in the lapse of few years this will be accomplish l ed.
 And again: if merchant trading ship can make this run of 374 miles in one day, at an average rate of fifteen and half knots an hour, it is apparent that our pres ent ships of war must be superseded-fast sailing being for the most part the element oftheir usefulness. The Portsmouth" and
 perhaps one other ship of war, have approx imated 10 this rate; all the rest should be replaced as fast as they wear out This last has been the opinion of the Ma " for several years, as they are in general
 terms heavy sailors, and unequal to their modern mode Of armament.