A/B      

Anti-Ship Booms

Adm

Admiral

A/S       

Anti-Submarine

ASW     

Anti-Submarine Warfare

ASWO

Africa Station War Order

A/T      

Anti-Torpedo

BdU      

Befehlshaber der U-Boote

BOT     

Board of Trade

Capt     

Captain

Cdr       

Commander

C-in-C

Commander-in-Chief

CGS      

Chief of the General Staff

CNIC

Cape Naval Intelligence Centre

Col       

Colonel

CSAB

Combined Shipping Adjustment Board

DHQ  

Defence Headquarters

DSO (N)

Defence Security Officer (Naval)

ERD     

Enemy Reports Department

FAA      

Fleet Air Arm

Flt Lt

Flight Lieutenant

Flt Off

Flight Officer

GAdm

Grand Admiral

GC&CS

Government Code and Cypher School

GOC      

General Officer Commanding

HDA     

Harbour Defence Asdic

HF/DF

High-Frequency/Direction Finding

HMAS

His/Her Majesty’s Australian Ship

HMS     

His/Her Majesty’s Ship

HMSAS

His/Her Majesty’s South African Ship

IJN        

Imperial Japanese Navy

Lt          

Lieutenant

Lt Cdr

Lieutenant Commander

Lt Gen

Lieutenant General

Maj       

Major

Maj Gen

Major General

MI5      

British Security Service

MI6      

British Secret Intelligence Service

M/S      

Minesweeping

MSCC

Merchant Shipping Control Committee

MWT

Ministry of War Transport

NCR      

Naval Censorship Representative

OB        

Ossewabrandwag

OID      

Operational Intelligence Department

OKM  

Oberkommando der Marine

RAdm

Rear Admiral

RAF      

Royal Air Force

RN        

Royal Navy 

RNVR

Royal Naval Volunteer Reserve

RNVR (SA)

South African Division of the RNVR

RM       

Royal Marines

SAAF

South African Air Force

SANF

South African Naval Forces

SANS

South African Naval Service

SAP      

South African Police

SAPEX

South African Ports Allocation Executive

SAPO

South African Post Office

SAR&H

South African Department of Railways and Harbours

SDF      

Seaward Defence Force

SIGINT

Signals Intelligence

SKL      

Seekriegsleitung

SNO      

Senior Naval Officer

SO         

Staff Officer

SO (I)

Staff Officer Intelligence

Sqn/Sqns

Squadron/Squadrons

TBR     

Torpedo Bomber/Reconnaissance

UDF      

Union Defence Force

UK        

United Kingdom

USA      

United States of America

VAdm

Vice Admiral

Wg Cdr

Wing Commander

WSA     

War Shipping Administration