The train of events which followed the firing on Fort Sumter in the space of three months brought the United States Navy face to face with the most exacting task of its history to that time: the blockade of a 3500 mile coastline extending from Cape Hatteras to the Rio Grande. Of the 50 warships available for service only 28 had auxiliary steam power, and it soon became apparent that even these were no match for the elusive steamers on which the Confederates came increasingly to rely for their military supplies. The blockade eventually became effective in preventing the South from selling its cotton abroad to replenish its armies at home, but in order to accomplish this a new Navy had virtually to be created. One hundred and fifty warships of various types were built for the blockade and another 75 cruisers were obtained by converting merchant steamers. Still another navy of ironclads and “tinclads” was brought into being to support army movements on the inland waters. All these operations pointed up one fundamental fact: the steam engine which alone made them possible had by 1865 put sail as a prime motive power for navies into the same limbo as the oar. The symbol and, to a very considerable extent, the architect of the change was the Engineer-in-Chief of the Union Navy, Benjamin Franklin Isherwood. The occasion, in this instance, did indeed call forth the man.
Appointed to the Navy in 1844 as a Second Assistant Engineer Isherwood served in all the Gulf operations of the Mexican War. In the principal action, at Vera Cruz, he found himself in the hottest spot of all, in the engine room of Tatnall’s Spitfire which lay unsupported under the guns of San Juan de Ulloa castle. He finished the war a Chief Engineer and was shortly afterward appointed technical assistant to Charles B. Stuart, the Engineer-in-Chief of the Navy. In a letter so cogently argued as to be included in the Secretary’s Annual Report for 1851 Isherwood began the battle to put the service in the van of technical progress which he continued for the rest of his professional life. He pointed out that boiler power per unit weight had doubled in less than a decade, and he urged the re-boilering of the pioneer Mississippi and her sister steam frigates even though their plants were, in the eyes of senior naval officers, relatively new. Another spell of sea duty in the San Jacinto which included active service at the Barrier Forts near Canton was followed, in March 1861, by Isherwood’s appointment as Engineer-in- Chief.
Congress, responding to the emergency created by the unprecedented wartime expansion of the Navy , established the Bureau of Steam Engineering in July, 1862, and the infant grew so rapidly that at the end of hostilities it overshadowed all the other bureaus. Isherwood, its chief, putting in normal work days of 16 hours, was personally responsible for the design of main engines in a majority of the new ships, and in addition he handled the details of bureau administration and supervised the construction, installation and repair of all naval machinery.
In setting up a blockade on larger scale than had ever been attempted before, even by the “storm tossed ships” that brought Napoleon to his knees, the Navy Department was guided at every step by Isherwood’s counsel. He suggested that an offshore line of heavy ships be stationed a hundred miles out and an inshore line cover the inlets and harbor mouths. He supplied designs for the machinery of the 20 Hassalo, Contoocook, and Antietam class cruisers which were laid down to man the outer line, though not all of these were completed. For shallow waters and the rivers his “double- ender” gunboat concept was adopted, and Bureau engineers under his direction supplied contractors with designs for the direct- acting paddle engines. But Isherwood made his distinctive contribution to practical naval engineering in the “Alabama chaser” Wampanoag, finished a couple of years after the close of the war.
The idea of this kind of fast cruiser originated with him. The Navy Department, however, took advantage of the opportunity presented by authorization to construct seven of the type to settle the bitter controversy over engine design which had flared since the first days of the war, and contracted with leading shipbuilders and engineers, including John Ericsson, to supply engines of their own design for the various ships in competition with the Bureau. In the steam trials that followed the Wampanoag won hands down. Isherwood, unlike his competitors, fully understood the need to avoid racking strains in wooden hulls. Accordingly, the Wampanoag’s engines were fitted with gears which doubled the revolutions of the propeller shaft in relation to those of the crankshaft and thereby minimized the number of reciprocations of heavy engine parts. At 64 propeller revolutions the Wampanoag achieved a sustained sea speed of 17 knots, four more than any other warship afloat and a rate not attained by another American naval vessel for twenty years.
Meanwhile Isherwood was engaged in notable research. His two volumes of Engineering Precedents which appeared in 1859 represented the first systematic attempt of an American engineer to determine power losses through friction in a marine engine. At the height of the Civil War he published another two volumes of Experimental Researches in Steam Engineering which were quickly translated into six European languages. He was the first who had the courage to attack the classic theories of Watt and Marriott and to establish the point beyond which further expansion of the working charge in an engine cylinder produces net loss rather than a gain. And that point, he proved was earlier in the stroke than was believed by other engineers in that day of low working pressures. The fact not only created astonishment but brought on Isherwood a storm of personal and professional abuse. But it also led directly to the adoption of higher steam pressures and the compound engine.
Isherwood inaugurated systematic engineering experimentation by the United States Navy. He was the first to show the proper way to test an engine and determine where the losses lay. To Rankine’s deductions in thermodynamics relating to the “ideal case” he added the physical theory of thermal and dynamic losses which made the applied science of the heat engine of practical value to the engineer.
When peace settled over the land after Appomattox no threat to the national security appeared from abroad and the Navy experienced drastic retrenchment. The hard- driving Isherwood failed of re-appointment to the Bureau when his tour expired in 1869, and his floating powerhouse, the Wampanoag, was indefinitely laid up. In the interests of economy the General Order of June 18, 1869, forbade commanding officers to use coal except in extreme emergency, and added that they “must not be surprised, if they fail to carry out the spirit of this order, if the coal consumed is charged to their account.” In justice it must be said that the marine engine was still a prodigious consumer of fuel. Some years later, in 1875, the British cruisers Topaze and Doris, buffeting monsoon headwinds in the Indian Ocean, reached Trincomaly with the former feeding furnaces with masts, spars, and the more weevily of her biscuits mixed with coaldust. The latter was stoking hemp cables. The marine engine was also highly unreliable; up to the early 1890’s transatlantic liners of the largest size were on occasion left helpless at sea and unable to proceed to port except under tow.
Understandably it has come to be believed that American naval engineering went into a long coma during the quarter century after the Civil War. The facts, however, hardly bear out the assumption. Four years after the Wampanoag’s triumphant performance Congress authorized construction of the three Ranger class iron cruisers, primarily powered by compound engines equal to the best foreign units of their size. A decade later, in 1883, the Bureau was engaged in designing what were then considered modern engines for the recently authorized cruiser Chicago, the largest ship of the new steel Navy. By 1893 stagnation in American naval construction was definitely over, and in that year the Bureau enjoyed the satisfaction of watching its engines drive the new Minneapolis more than 23 knots to a world’s speed record for seagoing warships.
In these years Isherwood served on various boards but chiefly concentrated his energies on the investigation of propeller problems. Before his retirement in 1884 he compiled a body of data which served usefully to promote the later definitive propeller research of Admirals David W. Taylor and Charles W. Dyson. He was the acknowledged dean of the engineering profession in the United States when he died in his ninety-third year on June 19, 1915.
A worthy successor to the great American whose name he bore, Benjamin Franklin Isherwood served his country with distinction in science and in war. The relation of logistics to military victory has received proper recognition outside the military profession only in recent times. It is therefore regrettable but wholly explicable that historians have been less perceptive of Isherwood’s achievements than a wartime subordinate, later head of the engineering school at Cornell University, who wrote: “It is, of course, true that he had at his command all the enormous resources of his bureau and the Navy Department, and could secure the aid of the ablest men of his corps; but the organization and conduct of such enterprises, at such a time and under such extraordinarily difficult conditions ... is evidence of the possession at once of moral, intellectual, and physical powers far beyond the average, and a spirit and ambition such as few men, even among the famous characters of historic times, have either possessed or concentrated upon any great purpose.”