Glossary, Abbreviations

A	(German) Achtzig Meter, KTB shorthand meaning ‘eighty metres’. Thus a boat at a depth of 110 metres could be referred to as ‘A+30’.
ASDIC	Term applied to the sonar equipment used for locating submerged submarines. A powerful and effective weapon, it emitted a distinct ‘ping’ when locating the target. The word is an acronym for Anti-Submarine Detection Committee, the organisation that began research into this device in 1917.
BdU	(German) Befehlshaber der Unterseeboote, or Commander U-Boats.
‘Bold’	(German) Short for Kobold (goblin), an acoustic decoy, known also as the ‘submarine bubble target’, comprising a small, cylindrical, mesh container filled with calcium hydride. When ejected from a submerged U-boat, the compound reacted with sea water and gave off hydrogen bubbles—and thus a false echo to ASDIC operators. It was simple but effective.
cbm	Cubic metres
‘Eel’	(German) Aal, a slang expression for torpedo.
‘Enigma’	(German) Coding machine used by German Armed Forces throughout the Second World War.
FdU	(German) Führer der Unterseeboote, or Flag Officer for Submarines, responsible for a particular geographical region.
grt	Gross registered tonnage (or tons). A standard measurement of the size of a merchant ship, one ton equalling 100 cubic feet of cargo capacity.
Ing.	(German) Ingenieur, or engineering grade, e.g. Kaptlt (Ing).
Kriegsmarine	(German) Navy of the Third Reich.
KTB	(German) Kriegstagebuch, or War Diary. Kept by the commander during a U-boat’s patrol. His handwritten version was later typed for the official records. It included torpedo firing diagrams.
LI	(German) Leitender Ingenieur, or Chief Engineer.
‘Lords’	(German) Slang term for naval ratings.
Luftwaffe	(German) Air Force.
OKM	(German) Oberkommando der Kriegsmarine, or Navy High Command.
OKW	(German) Oberkommando der Wehrmacht, or Armed Forces High Command.
Ritterkreuz	(German) Knight’s Cross of the Iron Cross.
Sperrbrecher	(German) Barrage-breaker—a specialized mine destructor vessel.
Turm	(German) Conning tower.
U-Bootwaffe	(German) U-Boat Service.
UZO	(German) Überwasserzieloptik, or surface targeting device.
VLR	(British) Very Long Range. Used in conjunction with aircraft, often Liberators.
Vorpostenboot	(German) Coastal patrol boat (or ship).
Wabo	(German) Wasserbombe(n), or depth charge(s).
Wachoffizier	(German) Watch Officer. There were three separate U-boat watch crews, each consisting of an officer, a petty officer and two ratings. The ship’s First Watch Officer (IWO) would be the Executive Officer (second-in-command), the Second Watch Officer (IIWO) the ship’s designated Second Officer, and the Third Watch Officer (IIIWO) often the Obersteuer-mann (Navigation Officer). Their duties were typically divided into the following time frames: 0000 – 0400 (1st Watch), 0400-0800 (2nd Watch) and 0800-1200 (3rd Watch); and then 1200-1600 (1st Watch), 1600-2000 (2nd Watch) and 2000-2400 (3rd Watch). The duties of the IWO included the care and maintenance of the torpedo and firing system as well as the control of surface attacks; the IIWO handled administration regarding food and supplies as well as the operation of deck and flak weapons.
Wehrmacht	(German) Armed Forces.
‘Wintergarten’	(German) Nickname given to the open-railed extension astern of the conning tower, built to accommodate increased flak weaponry and known to the Allies as a ‘bandstand’.