APPENDIX No. 4. REPORT OF A BOARD OF ENGINEERS ON THE PATRICK "AUTO-MOBILE CONTROLLABLE TORPEDO." ENGINEER SCHOOL OF APPLICATION, U. S. ARMY, The papers sent to the Board are herewith returned. W. R. KING, Major of Engineers, commanding. The CHIEF OF ENGINEERS, U. S. A. REPORT OF A BOARD OF ENGINEERS. A report was made by a Board of Engineers convened by the following order, viz: SPECIAL ORDERS, No. HEADQUARTERS CORPS OF ENGINEERS, UNITED STATES ARMY, Washington, D. C., June 25, 1888. By authority of the Secretary of War, a Board of Officers of the Corps of Engineers, U. S. Army, consisting of Maj. William R. King, Capt. Edward Maguire, Capt. Solomon W. Roessler, First Lieut. Irving Hale, is constituted to meet at College Point, Long Island, on June 27, 1888, to witness a test of the "Auto-Mobile Controllable Torpedo" of Mr. J. N. H. Patrick. The Board will submit a report as to the result of the trial, and its opinion as to the merits of the torpedo. If, in the opinion of the Board, further tests are desirable, it is authorized to arrange with Mr. Patrick to that effect; said tests to be at Mr. Patrick's expense. By command of Brigadier-General Duane: CLINTON B. SEARS, Captain of Engineers, U. S. A. On receipt of this order it was arranged for Mr. Patrick to notify the Board whenever he was ready for a trial of the torpedo, and, in pursuance of this arrangement, the Board visited College Point, and witnessed a trial for speed on the 30th of June. Two members of the Board witnessed another speed-run on the 10th, and again on the 13th and 20th of July. Two members witnessed the process of making the gas and charging the tank on the 11th of July. ENG 89-32 497 The torpedo undergoing the trial was built for the French Gover ment, and the tests were made with a view to its acceptance by th agent of that Government. It belongs to the class of "self-moving," controllable torpedoes, an is a development of the Lay torpedo, which began to assume a prac cable form some sixteen years ago, and, after improvement by M Haight about 1881, became by still further improvement the "Patrick torpedo of the present form. A similar torpedo, but of somewh smaller dimensions, was tested and reported on in 1886 by the Board Engineers of which General Duane was president, and described f Lieutenant Schroeder, U. S. Navy, in papers on "Recent Naval Pro ress for 1887." The torpedo and its float are cylindrical in form, with conoidal end the former being 42 feet long and 24 inches in diameter, while the latt is 41 feet long and 18 inches in diameter, these two parts being co nected by flat vertical bars so that their axes are parallel and abo 4 feet from each other. Each of these parts consists of a copper she an eighth of an inch in thickness, brazed and riveted together. T float is filled with compressed cotton to exclude water in case it pierced by projectiles, and carries two slender guide-rods with sma flags attached, to enable the operator on shore to observe its rate a direction of motion. The weight of the torpedo loaded and ready to run is about 7,8 pounds. The torpedo proper is divided into seven compartments, beginning the forward end. The first compartment contains the charge of pounds of dynamite. The second compartment contains the start an stop apparatus, a two-cell firing-battery, and a pin projecting to t frout for closing the circuit when the torpedo strikes. A second brea in the firing circuit is held open by a spring when the engine is atres but is closed by the pressure of the gas when the engine is runn This break renders the torpedo safe when not in motion. The torpe as arranged, can not be fired by judgment from shore, but only on pact. With the three-wire cable, or one-wire cable, however, provis is made for such firing. In the former case the third wire carries firing current, and in the latter is accomplished by a step-by-ste mechanism. The start-and-stop apparatus consists of a piston which opens. closes the throttle and which is moved by gas admitted to one side the other through valves operated by a polarized relay, a current in o direction admitting gas to one side of the piston, and a reverse curre to the other. The third and fifth compartments contain heaters, to prevent t freezing of the gas by the intense cold produced by its rapid expansio The heaters consist of series of pipes of gradually increasing diamete through which the gas passes, and around which is a heating mix of sulphuric acid, lime, and water contained in separate receptacles a dumped together just before starting. The temperature produced is supposed to be about 600° F. In t torpedo case, over each heater, is a safety-valve set at 45 lbs. to relie pressure from any gas that may be formed by the heating mixture, by the breaking of the pipes carrying the carbonic acid gas. The fourth compartment is at the center of flotation and contai the flask of liquefied carbonic acid gas. The charge for a mile run is pounds, about 500 of which is used. The pressure in the flask is abo 600 pounds to the square inch at 28° to 320 F., the temperature which the gas is manufactured. The maximum pressure in the engine during the run, as indicated by an automatically-recording pressuregauge, is about 95 pounds. The sixth compartment contains the coil of two-wire cable by which the torpedo is electrically started, stopped, and steered, and which is paid out to the rear through the hollow propeller shaft. The seventh compartment contains the engine and steering apparatus. The latter is similar to the start-and-stop mechanism described above, a direct current admitting gas to a piston which moves the rudder in one direction, while a reverse current admits the gas through another valve and moves the rudder in the contrary manner. The propeller bas two blades of 42 inches pitch, and is 31 inches in diameter. It makes about 1,595 revolutions per mile. It is driven by a very compact form of direct-acting engine with six 3-inch cylinders, having 7 inches stroke, and making 700 to 800 revolutions per minute. These cylinders are arranged around and parallel to the propeller-shaft, which is hollow and serves the double purpose of an exhautt pipe and a thimble through which the insulated steering cable is paid out, in addition to its usual office in driving the propeller. The piston rods of the six cylinders are provided with guide-rods and friction-rollers, which work in a groove cut obliquely around the surface of a cylinder which forms part of the propeller shaft, so that at each double stroke of a piston the propeller shaft makes a complete revolution, and there are always four of the pistons acting with full force, while two are passing the dead points. The operation of making the gas and charging the receivers was witnessed by two members of the Board and appeared to be a remarkably simple and easily conducted operation, the only men employed in it being ordinary laborers, who simply followed a few plain directions. The gas generating apparatus is double, one generator being worked while the other is being charged with acid and soda. Each generator consists of a spherical receptacle for acid above and connected to a cylindrical receptacle for bicarbonate of soda, the connecting pipe being closed by a stop-cock. The two receptacles are connected by a pipe, which equalizes the pressure in the two and allows the acid to flow into the soda compartment. A little acid is let in upon the soda, and the mixture stirred by means of a crank projecting through a stuffing box. The gas passes through a purifier to a reservoir, to which is attached a pressure gauge. When the pressure reaches 600 pounds a cock is opened in a pipe leading to the flask, which is immersed in ice and salt, and the gas passes to the flask. When the pressure, thus relieved, falls to about 500 pounds, a little more acid is let in upon the soda, the stirring is renewed, and this operation is repeated until the charge of acid and soda is exhausted, when the generator is cut off from the reservoir and recharged, while the gas-making proceeds with the other generator. The apparatus is abundantly strong, and there seems to be little possibility of an accident. Mr. Haight states that they have been using the apparatus for many years, and have never had an accident of any kind. The cost of the gas, including labor, is 16 cents to 17 cents per pound. With certain proposed improvements it can be made cheaper. The torpedo is started, stopped, and steered by electricity, communicated through a double cored insulated wire, 9.64 of an inch in diameter, coiled in one compartment of the torpedo and paid out through the hollow propeller shaft as the torpedo advances; 8,400 feet of this wire can be carried, and a greater length could be provided for if de sired. The quantity of carbonic acid carried is sufficient to run a mile at th highest speed attained, with considerable surplus, and this quantit could also be increased if necessary. In the trials witnessed by the Board the following speed tests wer made, viz: And by making some changes in the valves, so as to cut off at tw thirds stroke, Mr. Patrick claims to have run the mile in two minutes an twenty-seven seconds, or at the rate of about 24 miles per hour. A though the Board did not witness this last run, there is no question a to the power of the torpedo to make all necessary speed, and Mr. Patric offers to guaranty a speed of 22 miles per hour in case he contracts t make any torpedoes. No special trials calculated to test the steering capacity of the to pedo were made, but it is understood that such trials are contemplated and the Board has been invited to be present. So far as could be judge from the runs made before the Board the torpedo responded prompt when the steering switch was operated, and she appeared to be unde complete control of the operator. Perhaps the best thing that can be said of this or of any similar in vention is that in every case it did exactly what was required withou a hitch, went off at the appointed time, and without accident or misha of any kind. The general discussion of questions relating to auto-mobile torpedoe and their value as a part of our system of sea-coast defense is beyon the scope of this report, but a few words on the subject may not be on of place. The prime object of this class of weapons is to place a destructiv charge of dynamite or some other high explosive in contact or danger ous proximity to the hull of a ship at reasonable distance and explod it at the proper time. The more important factors involved in this problem are: First. Facility of delivery at the proper place in good order, launching. Second. Simplicity of mechanism and certainty of action. Fourth. Range of action. Fifth. Facility of directing. Sixth. Capacity of chamber for explosives. Seventh. Cost, and skill required in construction. Eighth. Questions of storage, preservation, etc. Ninth. Safety in handling. Tenth. Capacity for circumventing booms, nets, etc. an In regard to the first of these questions it will be noticed that th size and weight of the torpedo ready for action are such as to requir suitable ways for launching, and there will also be required at some co venient point the apparatus for generating gas. In this respect occupies an intermediate position between the Sims torpedo, for exam ple, which requires more and the Howel which requires less prepara tion for launching; the latter, however, is not controllable after launch ing. |