Special Board on Anti-Submarine Devices to Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters
NAVAL DISTRICT BASE
NEW LONDON, CONNECTICUT.
21 March 1918.
From: Special Board on Anti-Submarine Devices.
To : Commander, Naval Forces Operating in European Waters.
Via : Commander, Naval District Base.
SUBJECT: Report of progress on Anti-Submarine Devices.
Reference: (a) Your let. 0.4.6799 of 19 Jan. 1918.
1. In accordance with request in reference (a), there is forwarded herewith a copy of the weekly report of the Board, dated March 11, 1918.
2. Please acknowledge receipt.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
1st indorsement. NAVAL DISTRICT BASE, New London, Ct.
22 March 1918.
From: Commander Naval District Base.
To: Commander Naval Forces Operating in European Waters.
A. J. Hepburn
From: Special Board on Anti-Submarine Devices.
To : Bureau of Steam Engineering.
Navy Department (Operations).
SUBJECT: Report of progress of tests on anti-submarine devices.
Reference: (a) Bu.S.E.let.243452-797-L, 13 August 1917.
1. The following is a report of the progress on the principal development work and tests of the different problems undergoing experiment at the Stations under the supervision of this Board. . . .
A test on the D-3 was held on March 11th and 12th has been reported upon. The object of the test was to secure information on the M-B-S-B Tube. Two very short dives were made while a noise-making boat, the POLLYANNA, circled and maneuvered as directed. Due to the development of engine and motor trouble, the tests were postponed for the time being. The period of testing was so short that no definite data were dept [i.e., kept].
The housing and packing seemed to be in very good shape and operated quite satisfactorily, turning easily and still not leaking. In several minor details improvements were suggested which will be made before another test is carried out. The motors were not started at all and the ship drifted and rolled as the sea was rough. The tube was very noisy until about six (6) feet below the surface where it became very quiet. While lying on the bottom two propeller sounds were observed, one very loud and distinct with a rhythm of five beats and a space, cycles about 200 p.m. This was taken to be submarine and the direction given was that in general of the OWERA with which two submarines were known to be operating. The other sound was confused and the time too short to locate it exactly. The boat returned to the harbor without obtaining further data. Further tests are required before conclusions can be drawn.
-NASH FISH TESTS-
The Fish was taken out as scheduled, but due to the break-down in the engines the submarine did not appear and a rough test was made listening to passing tugs. In the afternoon the submarine came out a heavy snow storm prevented further operations. Another test is to be run soon with a submarine.
-DEEP SEA CHASER TEST-
The object of this test was to secure direct comparison of an M-F Tube and a K-Tube at long distance in comparatively deep water. It was arranged to carry out the tests, lasting three days, in water of from 100 to 1000 fathoms, South of Block Island.
The sub. chasers Nos. 254, 178 and 323 were in operation, following predetermined courses but keeping in communication with each other. No. 254 was equipped with an old-type M F Tube and the K-Tube.
A record was kept of the bearings of each vessel from each other observed from the bridge, ship’s head angle, and all engine room orders at the exact time. Acoustic readings were taken also. All bearings were corrected to true magnetic bearings and plotted against time.
Unfortunately the data was kept very carelessly, no deviation charts were obtainable for the compasses, very seldom check readings were made on the K-Tube set, and the angle of the floats only occasionally observed. There is no indication in the majority of cases which of the two angles it was intended to use on the K-Tube readings. It was, therefore, only after a great deal of cutting and trying and selecting the readings that any intelligible results were obtainable. On the second day the water was rough, and the vessels lay listening to a large vessel passing by. There are indications that it was heard before it was seen, but no definite proof as the data taken was so meager and so infrequent.
Inasmuch as no definite conclusions can be drawn, due to the carelessdata taken, further tests are to be held under better conditions...
-ELECTROSTATIC CONDENSER DETECTOR-
The wiring from the outboard condensers on the JOUETT to the Captain’s cabin and the installation of the electrical compensators and amplifiers in the cabin has been completed. All of the condenser receivers were found to be without defects and listening when at anchor, the noise made by boats in the river shows that the receivers are highly sensitive and that the electrical compensator is a practical instrument. These preliminary tests indicate that, with the condensers clamped rigidly to the hull of the vessel, they are liable to considerable disturbance from noises on the boat conducted to the receivers through the shell. (Riveting, pounding, etc.) Whether this is worse than in the case of other types of receivers has not yet been determined but it is probable that this effect can be reduced...
Preliminary tests with the 24-inch searchlight on the roof of the Station have been made. The signals were very definite up to five miles with either an 11-inch or 16-inch receiving mirror although received through a driving sleet which covered the receiver. At a distance of 1-1/2 miles, sweeps covering an arc of 20 degrees in five, ten and twenty seconds time were tried and gave indications that the shorter time sweeps were better for picking up. A test was also made of the increase in intensity with approach of a beam spread 15 degrees. A decided increase in intensity was found when distance was reduced from 1-1/2 miles to 1/2 mile. A test was carried out with the 24-inch searchlight on Experimental Station roof to find whether boats could determine when they ran into the invisible beam and follow it into a darkened harbor. The beam was directed to the West of the New London Ledge Lighthouse and the THETIS proceeded to a distance of 8 or 9 miles and then crossed the beam six times. There was no difficulty or uncertainty about picking up signals at each crossing. The spread of the beam at this distance was such that it took two to five minutes to cross the beam depending upon angle between course of the THETIS and axis of the beam. The THETIS then followed the beam into the harbor with the observer on the bridge directing the course when the Captain had purposely gotten out of the beam three times. At intervals, shutter signals were sent but, under existing conditions, these could not be received readily. Two complete 16-inch sending and two 11-inch receiving outfits have been received for testing on convoys...
-MAGNETIC OR ELECTROMAGNETIC METHOD OF DETECTION-
... On March 10th a Bush magnetic apparatus aboard the THETIS was tried out for range of detection on surface vessels. The results were far from satisfactory. The large detector coil picked up all sorts of disturbances, such as commutating noises, aboard ship; atmospheric static, inductions from land power circuits, etc. In addition to this the range of detection of surface vessels is less than 25 feet...It seems inadvisable to do any further work with a coil circling the ship...
-EFFECT OF DEPTH BOMB ON DETECTING DEVICES-
A brief summary of a preliminary report on this problem shows the following results. All the microphone buttons on the sea phones, rats, etc., were destroyed. Broca Tubes with metal diaphragms were badly deformed. Rubber tips were uninjured. Electrostatic condenser receiver was uninjured. Shielding screens were destroyed...
Results of tests on this device reported on in last two reports were confirmed. It was found that with Device No. 21 towed at 10 knots on 1000 feet of cable in deep water there was considerable thrumming, even with the anti-hummer attached. The addition of 20 pounds of lead to the keel of Device No. 21 apparently had no effect. In spite of this thrumming, however, the direction of sound coming from the towing vessel and from other vessels passing near by could easily be determined...
-SUBMERGED RADIO DEVICE – (RECEIVING)-
With the K-8 fitted with a trailing antennae at a depth of about 5 feet signals from the Naval Radio Station were received up to about two miles. With the K-8 submerged at a point ten miles from the Naval Station strong signals were received when at a depth of 10 feet. As the boat submerged further, until about eighteen feet of water were above the antennae, the signals were less intense.
The apparatus was transferred from the K-8 to the K-4 and the K-4 submerged about twenty miles to the Southwest of the Naval Station and with 500 feet of trailing antennae submerged to a depth of 10 feet. Signals were easily received. At a submerged depth of 17 feet the signals became very weak...
C. S. McDowell