Lieutenant James C. Van de Carr, Commander, L-10, to Special Board on Submarine Devices
U. S. S. L-10,
20 September 1917.
From: Commanding Officer.
To: Special Board on Submarine Devices, Submarine Base, New London, Conn.
Subject: Elimination of noises on Vessels.
Reference: (a) SBSD letter 1019-999PV-L of September 18, 1917.1
1. Every effort has been made to eliminate noises on this vessel with considerable success. It was found that most of the noise made by a submarine, outside of propeller noises was due to one of the following causes:
(a) Loose and vibrating stanchions and life lines.
(b) Radio mast and aerial.
(c) Chain for deck anchor.
(d) Gear stowed in deck lockers.
(e) Loose flaps on opening in superstructure.
(f) Blowing and flooding tanks in trimming down and maintaining proper depth at very low speeds.
(g) Gyro compass.
2. The following action was taken:-
(a) Stanchions and life lines were removed. Permanent fittings were secured to the bridge and a light life line run around the conning tower which reduced this noise to a negligable amount.
(b) Radio masts and aerial were removed. It is believed that noise from this cause is negligable when running at low speeds.
(c) Deck anchor chain was secured in chain locker. The weight of the chain then keeps it from rattling. The anchor does not rattle on the bill board.
(d) Gear, such as buckets, deck swabs, etc., were removed from the superstructure and stowed below.
(e) The flaps or covers for deck openings were flimsy and poorly secured. The ship’s force secured these more permanently.
(f) When running at very low speeds it was found necessary to frequently change the amount of water in the adjusting tank. That is, if the boatswas running steadily at 40 feet it seemed to find a groove at that depth. The process of porpoising the periscope took several minutes and when the periscope showed above water the boat would continue to rise despite all efforts.
By blowing say 500 pounds out of adjusting, however, the boat could be brought up quickly, and by flooding at the proper time the momentum would be overcome and the boat made to submerge deeper.
The noise of blowing and flooding can be reduced to practically nothing by the following method:-
TO BLOW:
Place a pressure in the tank keeping the Kingston2 closed. After the pressure is built up, shut off the air and open the Kingston until the desired amount is blown out.
TO FLOOD:
Vent the tank with Kingston closed. Then close the vent and open the Kingston. About a thousand pounds can be placed in the adjusting tank without venting if there is no pressure in the tank to start with.
(g) It was found impracticable to muffle the noise of the gyro compass without making radical changes. The authorities at Nahant stated that this noise could not be heard anyhow.
3. The points brought out above are the only recommendations the Commanding Officer has to offer.
J. C. Van de Carr.
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Source Note: Cy, DNA, RG 45, Entry 517. Document reference: “95-.”
Footnote 1: This letter has not been found.
Footnote 2: A valve on ballast tanks used to let water in when the submarine wanted to dive.
