1 Clinical Psychologist: Doctorate Degree in Psychology (4 to 7 years of graduate school) 2  Industrial-Organizational Psychologist: Master's Degree (2 to 3 years of graduate school)  Forensic Psychologist: Master's Degree (2 to 3 years of graduate school); a doctoral degree is recommended.
Submarine Propulsion Systems. During World War II, most American submarines were powered by diesel-electric systems. This was a departure from earlier submarine power systems, which were direct drive types, little changed from the earliest boats. In this direct-drive power system, the diesel engine is directly connected to the propeller shaft.
They also invented torpedoes which were propelled by small electric motors, thereby introducing one of the most dangerous weapons in the world. Submarines are also called U-boats, which is short for Unterseeboot, the German word for undersea boat. The first nuclear-powered submarine, the USS Nautilus (SN-571), was launched in 1955.