Page:Popular Science Monthly Volume 44.djvu/183

Rh others again, like the Chicago, Newark, Baltimore, and San Francisco, are designed for purposes of general utility, such as protecting our mercantile interests abroad, the one feature emphasized being endurance, with those of speed, protection, and armament very fairly developed. Our gunboats of the Yorktown and Machias types are miniature cruisers, except that speed has been sacrificed to enable them to carry heavy batteries; at present they are constructed entirely of steel, although many fruitless efforts have been made to adopt in this class the style of construction known as composite that is, all the parts of steel as is customary, except the outer covering of the hull, which is formed of wood planking coppered instead of steel plating. This system has been most earnestly and ably advocated by Chief Naval Constructor Philip Hichborn, and has formed the subject of special reports by him to the Navy Department, but the wording of the congressional appropriations has been such as to preclude its adoption.

The advantages to be gained are cheapness and ease of maintenance, freedom from fouling and consequent ease of propulsion, with the ability to keep the sea for long periods without being docked. All vessels of war are in a certain sense compromises between speed, endurance, protection, and armament; no one feature can be largely developed without corresponding sacrifices in the development of the others: for example, if great speed is required, it entails machinery of great power and weight with a large supply of coal; the weights, therefore, of the other main features must necessarily be reduced in order to emphasize that of speed; therefore, when Congress has appropriated for a certain type of vessel and fixed the limit of cost, a very careful study of all existing vessels of the desired type is made by the designing staff of the construction department, the particular requirements of the service are considered, the features to be emphasized determined, and the results embodied in a carefully prepared design. It is a very usual custom, and perhaps a natural one, for the press, when the design is made public, to compare it with some similar vessel of a foreign navy whose conditions of service are very dissimilar, sometimes to the seeming disadvantage of the proposed vessel, especially when such criticism may have been suggested by private builders who desire greater latitude in certain directions, and the general public may receive the impression that the best has not been attained; but to those who know the care and study given to the preparation of the design in view of the service required, and are able to comprehend fully its military value, the conclusion is very different. Taking, then, our battle-ships, we find the highest representative in the Iowa (Fig. 1), now building at the Messrs. Cramp's, which has a displacement of 11,250 tons, and carries a battery of four