THE “STILETTO”
The versatility of the Herreshoffs has appeared in their famous boiler improvement, and in the great variety of vessels they have built. The “Stiletto” only ninety-four feet long, over all, astonished the yachting world in 1885. On June 10, she beat the “Mary Powell” two miles in a race of twenty-eight miles on the Hudson. At one time, the “Stiletto” circled completely around the big steamer and then moved rapidly away from her.
Secretary Whitney bought the “Stiletto” for the United States navy, in which she has done valuable service. She was followed, in 1890, by the still faster “Cushing,” whose record in the recent Spanish-American war is so well known.
Admiral Porter wrote to Secretary of the Navy Chandler, that the little Herreshoff steam launches were faster than any other owned by the government, their great superiority showing especially against a strong head wind and sea, when they would remain dry while their rivals required constant bailing. They were better trimmed, lighter, more buoyant, and in every way superior in nautical qualities, and twice as fast as others in a gale.
Nineteen vessels have been built by this firm for the United States government.
“There is a certain speed that attaches to every vessel, which may be called its natural rate,” says Lewis Herreshoff; “it is mainly governed by its length and the length of the carrier wave which always accompanies a vessel parallel to her line of motion. When she reaches a speed great enough to form a wave of the same length as the moving body, then that vessel has reached her natural rate of speed, and all that can be obtained above that is done by sheer brute force. The natural limit of speed of a boat forty feet long is about ten miles an hour; of a vessel sixty feet in length, twelve and one-quarter miles; of one a hundred feet long, fifteen and three-fourths miles; of one two hundred feet long, twenty-two miles.”
As the speed is increased, this double or carrier wave, one-half on either side of the yacht, lengthens in such a way that the vessel seems to settle more the faster she goes, and so has to climb the very wave she makes. Hence the motive power must be increased much faster than the speed increases. Further, in order to avoid this settling and consequent climbing as much as possible, lightness of construction, next to correct proportions, is made the great desideratum in the Herreshoffs’ ideal boat. They use wood wherever possible, as it is not only lighter than metal, but is reasonably strong and generally much more durable. Wherever heavy strains come, a bracing form of construction is adopted, and metal is used also.
The engine of the “Stiletto” weighs ten pounds for each indicated horse-power; that of the “Cushing,” fifteen. The entire motive plant of the “Cushing” weighs sixty-five pounds for each horse-power; that of the “City of Paris,” two hundred. Comparing displacement, the former has eight times the power of the latter.
For four years our government kept a staff of officers stationed at the Herreshoff works to experiment with high-speed machinery, in which the firm then led the country. One of their steamers, ascending the St. Lawrence River to the Thousand Islands, ran up all the rapids except the Lachine, where a detour by canal was made. The Canadians were deeply impressed by this triumph.