Submarines as a surviving postwar strength

Russia secretly acquired an early submarine from Isaac Rice's Electric Boat Company and continued buying and building boats, including the German Karp class. Its remaining submarines were sent from Port Arthur to Vladivostok, where their concentration is presented as the world's first submarine fleet and gave crews combat experience. The undersea arm emerged from the war with respect and a comparatively credible base for expansion. Submarine warfare did not appear from nowhere in World War I because risky experimentation and operations had already been under way for years. The crews who served in these fragile early boats faced dangers that demanded unusual courage.