Abbreviations A group American escort group AAISSB Allied Anti-Submarine Survey Board ABC I American-British Conversations 1 ABC 22 American-Canadian appendix to ABC I, dealing with command arrangements in the Western Atlantic AC! Atlantic Convoy Instructions A/CNS Assistant chief of Naval Staff, RCN ACNS (T) Assistant chief of Naval Staff (Trade), RN AMC Armed merchant cruiser Als Anti-submarine ASW Anti-submarine warfare A&WI Atlantic and West Indies (Squadron), RN B group British escort group BAD British Admiralty Delegation, Washington BDienst German radio monitoring and decryption service BdU Befehlshaber der U-boote (commander-in-chief, U-boats) C group Canadian escort group C-in-C, WA Commander-in-chief, Western Approaches, RN cccs Commodore commanding, Canadian Ships (UK) CCNF Commodore commanding, Newfoundland Force CNEC Chief of Naval Engineering and Construction, RCN CNES Chief of Naval Equipment and Supply, RCN CNO Chief of Naval Operations, USN CNS Chief of Naval Staff, RCN co Commanding officer COAC Commanding officer, Atlantic Coast, RCN xxii Abbreviations COMINCH Commander-in-chief, USN CTF-24 Commander, Task Force Twenty-four, USN DAIS Director, Anti-Submarine, RCN DA/ SW Director, Anti-Submarine Warfare, RN DCOS Deputy chief of staff DHist Directorate of History, National Defence Headquarters, Ottawa DNP Director, Naval Personnel, RCN DOD Director, Operations Division, RCN DOP Director of Plans, RCN DSD Director, Signals Division, RCN DTD Director, Trade Division, RCN DWT Directorate of Warfare and Training, RCN EG Escort group FONF Flag officer, Newfoundland FSL First Sea Lord HF/DF High-frequency direction finding HMCS His Majesty's Canadian Ship HMS His Majesty's Ship HN or MS His Norwegian Majesty's Ship HX Fast eastbound convoy MF/DF Medium-frequency direction finding MOEF Mid-Ocean Escort Force MTB Motor torpedo boat NEF Newfoundland Escort Force NHB Naval Historical Branch, London NHC Naval Historical Center, Washington, DC NMCS Naval member, Canadian Staff, Washington NRC National Research Council, Ottawa NSHQ Naval Service Headquarters, Ottawa ON Fast westbound convoy ONS Slow westbound convoy PAC Public Archives, Canada PRO Public Record Office, London RDFO Radar officer RPV Revised patrol vessel (eg, a corvette with modifications) RIT Radio telephone SC Slow eastbound convoy SNEM Supervising naval engineer, Maritimes xxiii Abbreviations SO(A/S) Staff officer, Anti-Submarine SOE Senior officer, Escort SWIC Surface warning, First Canadian (Radar) USCG United States Coast Guard USNA United States National Archives, Washington VCNS Vice-chief of Naval Staff, RCN VLR Very long range vis Visual signalling WA Western Approaches WACI Western Approaches Convoy Instructions WLEF Western Local Escort Force WSF Western Support Force WIT Wireless telegraphy .