(A) G-Boat
(B) ** U-Boat
(C) S.W.A.G-Boat
(D) Underwater Vessel
EXPLANATIONS BELOW
Concept note-1: -Germany retaliated by using its submarines to destroy neutral ships that were supplying the Allies. The formidable U-boats (unterseeboots) prowled the Atlantic armed with torpedoes. They were Germany’s only weapon of advantage as Britain effectively blocked German ports to supplies.
Concept note-2: -U-boat, German U-boot, abbreviation of Unterseeboot, (“undersea boat”), a German submarine. The destruction of enemy shipping by German U-boats was a spectacular feature of both World Wars I and II.
Concept note-3: -Germany has commissioned over 1, 500 U-boats (German: Unterseeboot) into its various navies from 1906 to the present day. The submarines have usually been designated with a U followed by a number, although World War I coastal submarines and coastal minelaying submarines used the UB and UC prefixes, respectively.
Concept note-4: -German submarines – or unterwasser boats (U-boats) – were on a mission to destroy merchant vessels carrying supplies to allied forces in order to hinder their war efforts.