REFERENCE DOCUMENTS & RESOURCES - OFFICIAL ADMIRALTY DOCUMENTS
ADM 239/261: THE FIGHTING INSTRUCTIONS, 1939 (C.B.04027)
Updated 31-Mar-2007

This document is a modern transcription of a portion of Admiralty record ADM 239/261. This lengthy document contains the Admiralty's official fighting instructions. The original file is held at the The National Archives at Kew, London. This Crown Copyrighted material is reproduced here by kind permission of The National Archives.

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SECTION III.-RECONNAISSANCE, SEARCH AND PATROL

CONTENTS

(Note- Click on titles in blue below to view applicable sub-sections)
Clause Subject
140
 
141-147
141
142-143
144-146
147
 
148-151
 
152-153
 
154-156
 
157-159
 
160
 
161-169
GENERAL. Click here
 
SELECTION OF RECONNAISSANCE FORCES.
By day.
At night.
Types of aircraft available for reconnaissance.
Economy in the use of aircraft.
 
INSTRUCTIONS FOR AIRCRAFT EMPLOYED ON RECONNAISSANCE. Click here
 
INSTRUCTIONS FOR SURFACE VESSELS EMPLOYED ON RECONNAISSANCE. Click here
 
INSTRUCTIONS FOR SUBMARINES ON RECONNAISSANCE PATROL. Click here
 
ORGANISATION OF A NIGHT SEARCHING FORCE. Click here
 
ENEMY REPORTS. Click here
 
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SECTION III.-RECONNAISSANCE, SEARCH AND PATROL

GENERAL

140. The following instructions apply in particular to reconnaissance, but ships employed on search or patrol should also use them as a guide. Reconnaissance is carried out in order to discover whether any enemy ships are at sea in a given area ; search to obtain full information about enemy forces initially located by reconnaissance. Reconnaissance may be said to end and search begin as soon as the first enemy report is made by a ship or aircraft. In certain circumstances, patrol will be an aid to or will replace reconnaissance, and may result in large enemy forces being brought to action by the main fleet. The instructions for search and patrol by surface craft are given in O.U. 5415/36.

SELECTION OF RECONNAISSANCE FORCES

BY DAY
141.
Aircraft provide the normal and most economical means of reconnaissance by day. The limitations of aircraft, however, and their unsuitability in some conditions will frequently require that surface forces or submarines should supplement or replace aircraft engaged on this duty. Submarines are specially suitable for reconnaissance duty in waters controlled by the enemy.

AT NIGHT
142.
Small cruisers and destroyers are the most suitable units for reconnaissance at night, owing to their handiness and small silhouette, which makes them difficult to see. Submarines can seldom be employed on night reconnaissance though their small silhouette may make them of value in some circumstances.

143. Aircraft are not normally suitable for night reconnaissance, though they may be of considerable value in supplementing surface reconnaissance, especially in bright moonlight and particularly when the position and composition of enemy forces is approximately known. They will always have difficulty in identifying ships at night.

TYPES OF AIRCRAFT AVAILABLE FOR RECONNAISSANCE
144. Carrier-borne aircraft.
When the fleet is at sea, carrier-borne aircraft will be employed for reconnaissance duties if available.

145. Catapult aircraft. The difficulties of operating catapult aircraft render them unsuitable for reconnaissance unless the sea is so calm that they can be recovered without difficulty. They should not be used for this duty if an aircraft carrier is in company with the force at sea.

146. Shore-based aircraft. Naval reconnaissance duties may also be undertaken by shore-based aircraft, but it mut be remembered that the personnel of squadrons detailed for this duty may be inexperienced in working with naval forces and in recognising ships. Care should be taken that, when practicable, information is furnished to General Reconnaissance Squadrons regarding the types of friendly ships in the area of reconnaissance, and the means of identification in use between ships and aircraft.

ECONOMY IN THE USE OF AIRCRAFT
147.
The number of aircraft available for reconnaissance duties will always be limited ; consequently, the economical employment of aircraft to achieve the object of any operation should always be an important consideration.

INSTRUCTIONS FOR AIRCRAFT EMPLOYED ON RECONNAISSANCE

148. Air reconnaissance will be established by the Senior Officer, aircraft carriers, in accordance with the Admiral's directions. He will also decide whether flying is possible and whether to recall aircraft if the weather deteriorates. He should inform the Admiral of any alterations made to the original duties assigned to aircraft.

149. The principle duty of reconnaissance aircraft is to locate and report the enemy main force and aircraft carriers, subsequently keeping them under observation, whilst endeavouring to remain unseen. All other enemy forces sighted should be reported. The decision whether reconnaissance aircraft should carry bombs will be at the discretion of the Senior Officer, aircraft carriers, subject to the requirements of the Admiral.

150. Detailed instructions for reconnaissance aircraft are contained in current Fleet Air Arm publications. Before the start of a reconnaissance, aircraft will normally be given information to cover the following points:-

(a) Action to be taken after sighting and reporting an enemy.
(b) Action to be taken by aircraft on receipt of enemy reports from their consorts. Such reports may not be intercepted by all aircraft.
(c) Action to be taken when reconnaissance aircraft are armed with bombs.
(d) Circumstances in which aircraft may deviate from the courses ordered. Some latitude should normally be given to a wing aircraft sighting vessles outside the reconnaissance area.

151. In the absence of particular instructions, aircraft must be prepared to act without hesitation on their own initiative. As a general rule, action should be taken as follows:-

(a) Sighting a strange vessel. The aircraft should take the necessary action to avoid being seen and should then identify the enemy and make a report. It is important that the enemy should be unaware that he has been detected ; visibility from ships is frequently better than from the air. The subsequent action to be taken will depend on the object of the reconnaissance and the enemy forces expected in the area. Very good reasons should exist before touch with heavy ships or aircraft carriers is relinquished.
(b) Sighting enemy aircraft. A formation of aircraft sighted should be reported immediately. Single enemy aircraft should not be reported. The course steered by enemy aircraft may be an indication of the direction of any enemy force of aircraft carriers.
(c) Sighting a submarine. Any submarine sighted should be attacked immediately. The submarine should be reported if in a position to attack any units of the fleet, or is a counter-attacking force is in the vicinity.
(d) Sighting M.T.Bs. Enemy M.T.Bs. should be reported and attacked.
(e) Bombs in reconnaissance aircraft. In circmstances when reconnaissance aircraft are armed with bombs, the primary duty of reconnaissance should always take priority over bombing attack. Attacks should only be carried out if conditions appear favourable for surprise, or when aircraft must return to an aircraft carrier to refuel. In this case, enemy aircraft carriers should be selected for attack in preference ot other classes of ship.
(f) Sighting an enemy at night. At night aircraft should not attempt to escape observation by the enemy. The possibility of surface vesssels successfully engaging aircraft in the dark is remote and should be discounted. Close touch should be maintained with enemy forces encountered unless specific instructions to the contrary have been given.

INSTRUCTIONS FOR SURFACE VESSELS EMPLOYED ON RECONNAISSANCE

152. In the absence of specific instructions, the Commanding Officer of a ship employed on reconnaissance must have the following points clearly in his mind before contact occurs:-

(a) Sighting an enemy vessel. The first measures will usually be to alter course and speed and make an alarm report. A quick decision and immediate action to engage, shadow or evade are invariably necessary.
(b) Sighting merchant ships, suspicious vessels or aircraft. Obviously friendly merchant vessels should not be molested, but vessels suspected ot hostile intent should be sunk and the crews taken off, if the object of the reconnaissance is not jeopardised by the loss of time involved (see Clauses 122, 123). Formations of enemy aircraft should be engaged and reported. Single enemy aircraft should not be reported, unless this is possible by V/S. but may be engaged.
(c) Sighting a submarine. If in a good position to attack, an attempt should be made to destroy the submarine by gunfire, ramming and depth charges. If the chances of successful attack are remote, the submarine should be given a wide berth. Submarines in a position to attack units of the fleet, or in the vicinity of a counter-attacking force, should be reported.
(d) Receipt of an enemy report from a consort. Ships should work up to high speed, but should not normally close the position of first contact until the situation becomes clear and indicates that such a course is desirable.
(e) Sighting an enemy at night. Unless the situation requires that fire should be opened immediately, ships should open the range by either turning bows-in and reducing speed, or stern-on and increasing speed, according to whether the sighting ship is abaft or before the beam of the enemy when first contact takes place. They should subsequently shadow.

153. Use of D/F. Ships employed on reconnaissance duties should make full use of their D/F equipment.

INSTRUCTIONS FOR SUBMARINES ON RECONNAISSANCE PATROL

154. The variety of circumstances in which a submarine may find herself on reconnaissance duty and the likelihood of communication difficulties make it necessary that a wide discretion should be given to Commanding Officers. As a general rule, submarines should endeavour to report enemy vessels sighted without their presence becoming known. In some cases immediate reports may be of greater importance than their security. In the absence of specific instructions, discretion must be used in the risks incurred in making reports.

155. Maintenance of touch. In many circumstances it may be more important to follow and endeavour to keep touch with an enemy unit sighted than to maintain the patrol position ordered.

156. Attacks. Important enemy units should always be attacked, unless definite orders to the contrary have been issued. Submarine patrol orderd should normally contain definite instructions regarding attack on light craft. Submarines sighting enemy vessels at night should simultaneously fire torpedoes and make an enemy report, they should then dive.

ORGANISATION OF A NIGHT SEARCHING FORCE

157. If possible, ships to be employed on a night search should be organised some considerable time before dark. Instructions for ordering a night search are contained in the Signal Manual, Chapter XVIII, "Search and Patrol by Surface Craft" (O.U.5415/36), and in the Destroyer Fighting Instructions. The attacking force tables, the use of which is described in Part III of the Destroyer Fighting Instructions, will usually be the most convenient method of ordering a night search when time is short.

158. It is important that all ships to be employed on a night search are in company with the Senior Officer of the search before dark, and that a reference position is issued before ships start to spread. Whenever possible, the search should be so arranged that all searching units know that any vessel sighted is an enemy.

159. When searching for enemy forces at night, it is not enough to locate and report units of the enemy's night screen only. The Admiral will require information of all enemy units encountered, but more especially of the enemy's main force and aircraft carriers.

ENEMY REPORTS

160. The primary object of any ship or aircraft employed on reconnaissance is to give the Admiral information about the enemy ; the first report of contact with the enemy must be made without delay. Ill-considered or inaccurate reports may have serious and adverse effects on the operations of other forces, and must be avoided. Therefore, reconnaissance units should normally make an "alarm report" on first sighting, and a full report after subsequent careful observation. (See Signal Manual, Chapter XVII). It is important for reconnaissance units to remain unseen until they have observed the course of the enemy, as it is probable that the latter will alter course as soon as he realises he has been sighted.

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