Rear Admiral William B. Caperton, Commander-in-Chief, Pacific Fleet, to Captain George B. Bradshaw, Commander, Pittsburgh
UNITED STATES PACIFIC FLEET
U.S.S. PITTSBURGH, FLAGSHIP
CONFIDENTIAL. 9 May, 1918.
To: Commanding Officer, U. S. S. PITTSBURGH.
Subject: Inspection of vessels encountered at sea.
1. The following policy will be carried out in regard to the determination of the character of vessels sighted during this cruise;
2. ENEMY.- It is probable that any enemy naval forces on this station will consist of one or more of the large sea-going type of submarine, probably of the “Deutschland” class. These may be accompanied by surface craft in the nature of supply vessels, decoys, prizes, or raiders. In approaching any surface craft it must be constantly born in mind that she may be accompanied by submarines.
3. BY DAY.- As far as possible, all vessels sighted by day will be examined to determine their character. In the case of ordinary vessels which present no suspicious circumstances, this examination will consist of passing close enough to verify the general description of the vessel as given in Lloyd’s Register, and, if practicable, to verify the name and other details, such as the appearance of the officers and crew on deck, etc. Inquiry will be made by visual signal of such ships regarding their identity, whether they have anything to report, their port of departure, and their destination. The following signals from the international Signal Book are hereby translated for convenience:
DV – Make your number
URS – Have you anything to report?
SI – Where are you from?
SH – Where are you bound?
TXB – Proceed on your voyage.
If everything appears satisfactory no further investigation will be made.
4. If the vessel requires further investigation, make preparation for boarding in the manner prescribed by current instructions, having due regard for the submarine menace, but before actually slowing to lower a boat, report the circumstances to the commander-in-chief for his decision as to whether to stop.
5. BY NIGHT.- Vessels encountered just before dawn will, if practicable, be kept in touch with, to be examined by daylight. Vessels encountered earlier during the night will be avoided, making careful note of whatever can be seen of them when sighted. The examination of vessels at night is not contemplated, and no lights of any kind should be shown to such vessels, except dimmed running lights as necessary to avoid collision, or blinker tube recognition signals when circumstances indicate their use.
6. Subject to the foregoing, the commanding officer will conduct the patrol operations and examination of vessels, informing the commander-in-chief promptly of action taken. He will alter the prescribed course at discretion in order to approach or avoid vessels , returning to the prescribed course when divergance therefrom is no longer necessary, and provided a return thereto involves no danger to navigation.
7. The flag signal force is placed at the disposal of the ship for the signal duty involved in this mission.