UB-II class submersibles

UB-2 class (1915-18) German Empire – 30 submarines, UB-18 to UB-47 UB-45 underway in 1916 The UB-II class. Second part

German Type II U-Boat - history, specification and photos

USS Delaware SSN 791 Commissioning Publication by Faircount Media Group - Issuu

H I Sutton - Covert Shores

E-class Submarine

How did the German U-boats perform in the WW 2 compared to WW 1, from a strategical point of view ? - Quora

U-boat - Wikipedia

U-Boat Wreckage Found - Crew Claimed They Were Attacked by Sea Monster

German Submarine Activities on the Atlantic Coast

NEMO Submarine

Was the U-boat the first submarine? - Quora

Submarine photos hi-res stock photography and images - Page 2 - Alamy

German Submarine Activities on the Atlantic Coast

UB-1 class submersibles (1914)

How fast can a German U-boat go? - Quora

German Type Ub I Submarine: Most Up-to-Date Encyclopedia, News & Reviews