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APPENDIX No. 4.

KEPORT OF A BOARD OF ENGINEERS ON THE PATRICK “AUTO-MOBILE CONTROLLABLE TORPEDO."

ENGINEER SCHOOL OF APPLICATION, U. S. ARMY,

Post of Willets Point, Whitestone, N. Y., August 15, 1888, GENERAL: I have the honor to transmit herewith the report of a Board of Engineers convened to report on the Patrick torpedo at College Point.

The papers sent to the Board are herewith returned.
Very repectfully, your obedient servant,

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. 31.

HEADQUARTERS CORPS OF ENGINEERS,

UNITED STATES ARMY, Washington, D. C., June 25, 1988.

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 pursu ance 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

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The torpedo undergoing the trial was built for the French Government, and the tests were made with a view to its acceptance by the agent of that Government.

It belongs to the class of "self-moving," controllable torpedoes, and is a development of the Lay torpedo, which began to assume a practicable form some sixteen years ago, and, after improvement by Mr. Haight about 1881, became by still further improvement the "Patrick" torpedo of the present form. A similar torpedo, but of somewhat smaller dimensions, was tested and reported on in 1886 by the Board of Engineers of which General Duane was president, and described by Lieutenant Schroeder, U. S. Navy, in papers on "Recent Naval Prog. ress for 1887."

The torpedo and its float are cylindrical in form, with conoidal ends, the former being 42 feet long and 24 inches in diameter, while the latter is 44 feet long and 18 inches in diameter, these two parts being connected by flat vertical bars so that their axes are parallel and about 4 feet from each other. Each of these parts consists of a copper shell an eighth of an inch in thickness, brazed and riveted together. The float is filled with compressed cotton to exclude water in case it is pierced by projectiles, and carries two slender guide-rods with small flags attached, to enable the operator on shore to observe its rate and direction of motion.

The weight of the torpedo loaded and ready to run is about 7,300 pounds.

The torpedo proper is divided into seven compartments, beginuing at the forward end. The first compartment contains the charge of 200 pounds of dynamite. The second compartment contains the start-andstop apparatus, a two-cell firing-battery, and a pin projecting to the front for closing the circuit when the torpedo strikes. A second break in the firing circuit is held open by a spring when the engine is at rest, but is closed by the pressure of the gas when the engine is running. This break renders the torpedo safe when not in motion. The torpedo, as arranged, can not be fired by judgment from shore, but only on im. pact. With the three-wire cable, or one-wire cable, however, provision is made for such firing. In the former case the third wire carries the firing current, and in the latter is accomplished by a step-by-step mechanism.

The start-and-stop apparatus consists of a piston which opens and closes the throttle and which is moved by gas admitted to one side or the other through valves operated by a polarized relay, a current in one direction admitting gas to one side of the piston, and a reverse current to the other.

The third and fifth compartments contain heaters, to prevent the freezing of the gas by the intense cold produced by its rapid expansion. The heaters consist of series of pipes of gradually increasing diameter, through which the gas passes, and around which is a heating mixture of sulphuric acid, lime, and water contained in separate receptacles and dumped together just before starting.

The temperature produced is supposed to be about 600° F. In the torpedo case, over each heater, is a safety valve set at 45 lbs. to relieve pressure from any gas that may be formed by the heating mixture, or by the breaking of the pipes carrying the carbonic acid gas.

The fourth compartment is at the center of flotation and contains the flask of liquefied carbonic acid gas. The charge for a mile run is 600 pounds, about 500 of which is used. The pressure in the flask is about 600 pounds to the square inch at 28° to 32° F., the temperature at

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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 has 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 33-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 desired.

The quantity of carbonic acid carried is sufficient to run a mile at the highest speed attained, with considerable surplus, and this quantity could also be increased if necessary.

In the trials witnessed by the Board the following speed tests were made, viz:

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And by making some changes in the valves, so as to cut off at twothirds stroke, Mr. Patrick claims to have run the mile in two minutes and twenty-seven seconds, or at the rate of about 24 miles per hour. Although the Board did not witness this last run, there is no question as to the power of the torpedo to make all necessary speed, and Mr. Patrick offers to guaranty a speed of 22 miles per hour in case he contracts to make any torpedoes.

No special trials calculated to test the steering capacity of the torpedo 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 judged from the runs made before the Board the torpedo responded promptly when the steering switch was operated, and she appeared to be under complete control of the operator.

Perhaps the best thing that can be said of this or of any similar invention is that in every case it did exactly what was required without a hitch, went off at the appointed time, and without accident or mishap of any kind.

The general discussion of questions relating to auto-mobile torpedoes and their value as a part of our system of sea-coast defense is beyond the scope of this report, but a few words on the subject may not be out of place.

The prime object of this class of weapons is to place a destructive charge of dynamite or some other high explosive in contact or dangerous proximity to the hull of a ship at reasonable distance and explode 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, and launching.

Second. Simplicity of mechanism and certainty of action.

Third. Speed-freedom from effect of wind and waves.

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.

In regard to the first of these questions it will be noticed that the size and weight of the torpedo ready for action are such as to require suitable ways for launching, and there will also be required at some convenient point the apparatus for generating gas. In this respect it occupies an intermediate position between the Sims torpedo, for example, which requires more and the Howel which requires less preparation for launching; the latter, however, is not controllable after launching.

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