Office of the Historian

File No. 763.72/2646½

The British Ambassador (Spring Rice) to the Secretary of State

Washington, April 28, 1916 .

My Dear Mr. Secretary: In accordance with a request received from Mr. Woolsey, I have pleasure in sending to you herewith a copy of the Admiralty instructions for armed merchant ships of October 20, 1915, which were communicated officially to Mr. Page by Sir Edward Grey and published in the press here on March 3 last. These are the instructions at present in force.

I have telegraphed to enquire whether masters of ships who disobey these instructions are liable to any penalty and shall not fail to inform you as soon as I receive a reply.

Believe me [etc.]

Cecil Spring Rice
[Enclosure]

Confidential

No. 741

Instructions for Defensively Armed Merchant Ships

A. The status of armed merchant ships

(1)
The right of the crew of a merchant vessel forcibly to resist visit and search, and to fight in self-defence, is well recognized in international law, and is expressly admitted by the German prize regulations in an addendum issued in June 1914 at a time when it was known that numerous merchant vessels were being armed in self-defence.
(2)
The armament is supplied solely for the purpose of resisting attack by an armed vessel of the enemy. It must not be used for any other purpose whatsoever.
(3)
An armed merchant vessel, therefore, must not in any circumstances interfere with or obstruct the free passage of other merchant vessels or fishing craft, whether these are friendly, neutral, or hostile.
(4)
The status of a British armed merchant vessel cannot be changed upon the high seas.

B. Rules to be observed in the exercise of the right of self-defence

(1)
The master or officer in command is responsible for opening and ceasing fire.
(2)
Participation in armed resistance must be confined to persons acting under the orders of the master or officer in command.
(3)
Before opening fire the British colours must be hoisted.
(4)
Fire must not be opened or continued from a vessel which has stopped, hauled down her flag, or otherwise indicated her intention to surrender.
(5)
The expression “armament” in these instructions includes not only cannon but also rifles and machine guns in cases where these are supplied.
(6)
The ammunition used in rifles and machine guns must conform to Article 23, Hague Convention IV, 1907; that is to say, the bullets must be cased in nickel or other hard substance, and must not be split or cut in such a way as to cause them to expand or set up on striking a man. The use of explosive bullets is forbidden.

C. Circumstances under which the armament should be employed

(1)
The armament is supplied for the purpose of defence only, and the object of the master should be to avoid action whenever possible.
(2)
Experience has shown that hostile submarines and aircraft have frequently attacked merchant vessels without warning. It is important, therefore, that craft of this description should not be allowed to approach to a short range at which a torpedo or bomb launched without notice would almost certainly take effect.
British and Allied submarines and aircraft have orders not to approach merchant vessels. Consequently it may be presumed that any submarine or aircraft which deliberately approaches or pursues a merchant vessel does so with hostile intention. In such cases fire may be opened in self-defence in order to prevent the hostile craft closing to a range at which resistance to a sudden attack with bomb or torpedo would be impossible.
(3)
An armed merchant vessel proceeding to render assistance to the crew of a vessel in distress must not seek action with any hostile craft, though, if she is herself attacked while so doing, fire may be opened in self-defence.
(4)
It should be remembered that the flag is no guide to nationality. German submarines and armed merchant vessels have frequently employed British, Allied or neutral colours, in order to approach undetected. Though, however, the use of disguise and false colours in order to escape capture is a legitimate ruse de guerre, its adoption by defensively armed merchant ships may easily lead to misconception. Such vessels, therefore, are forbidden to adopt any form of disguise which might cause them to be mistaken for neutral ships.

Admiralty War Staff
Trade Division
20th October 1915.