It always affords us pleasure to furnish a tangible exponent to the progress of Marine Architecture in every part of out continent, from the smallest coasting schooner to the noblest clipper which circumnavigates the globe. In a former number of the Magazine we published the lines of the Stag-Hound, the first of the numerous fleet of celebrated clippers which has been built by Mr. Donald McKay, at Boston, within a period of four years. Through his politeness we now publish the draught and calculations of the famous Australia racer, Lightning, one of the latest and sharpest ships which her builder has constructed. This vessel was built in 1854, and fairly reflected the skill of Mr. McKay at that period. She is owned in England, and sailed from Boston to Liverpool in 13 days and 20 hours, and, on her first trip to Melbourne and back, bore off the palm for speed on that route. She accomplished the outward run in 77 days, the return voyage 64 days; second outward passage, 75 days, homeward, 65 days; the shortest passage on record being 63 days. She is owned by the proprietors of Baine's Line of Liverpool and Australian packets, and her performances indicate a profitable model, beyond the mark of steamships, upon the route to which she has been eminently adapted.
The dimensions and calculations of the Lightning will be found as follows;
|Length on the load-line for calculations||227.50|
|Height of load-line, above base line||15.|
|Breadth on load-line, at dead flat||43.12|
|Area of load water plane, sq feet||3383.17|
|Exponent of the same||0.654|
|Centre of gravity of same abaft mid-length||3.34|
|Area of greatest transverse section, sq. feet||572.6|
|Exponent of the same||0.885|
|Location, abaft mid-length, of load-line||8.|
|Moulded displacement, in cubic feet||57.227|
|Moulded displacement, in gross tons||1635.|
|Exponent of the same||0.524|
|Centre of gravity below load-line||5.89|
|Centre of gravity abaft mid-length of do.||2.24|
|Moment of stability, S. 2/3 dx=||775744.|
|Height of meta centre above centre of buoyancy||13.53|
By European naval authorities such a model would be repudiated on account of the centre of gravity of displacement being found abaft of midlength of load line, but such authors have little weight with the independent modellers of America. And although the mechanical advisers of her owners have accomplished their purpose, by filling out the bow of the vessel to suit their crude notions of science, it will be found that some modification in the distribution of the propulsory power was all that was necessary (as we shall show in connection with her spar draught in our next issue) to make her all that could be desired even by the fogyistic advocates of full bows in the Old World.
It having been laid down by Chapman, the celebrated Swedish Naval Architect, that the centre of buoyancy should be determined forward of the mid-length of the load-line within certain arbitrary limits, because, from an analysis of the bodies of vessels which bore good characters at sea, he found this point so situated, more than half a century ago, that naval and marine architects of the Old World have never ventured to risk an experiment to test the value of this stale dogma. In England "experimental fleets have been built, none of which have ever established any marked distinction for the constructors, most of them having reached the ultima thule of scientific men, so called, because they have systematized hereditary knowledge, and trammelled themselves with formulas drawn from the half revealed mysteries of shipbuilding. The moderate dead rise of this remarkable ship is also at variance with naval learning. In fact, some builders are to be found in every part of the world, who, by this tie, are awaking to the belief, that the bow of a ship is the seat of life and motion, nay, intelligence itself may seem almost developed in this part of the body under the hand of the artistic delineator of form. In the Lightning the fuller end is the posterior, as it should be, for speed. But the strongest point is her stability, her depth of hold being chosen without regard to a violation of "tonnage" laws. This need no longer be done in vessels for British markets. The Lightning is a worthy example of an improving art.
Transcribed by Lars Bruzelius.
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Copyright © 1996 Lars Bruzelius.