1. An expendable underwater vehicle for use in training naval forces in anti-submarine warfare in ocean water, comprising: a body having a length along a longitudinal axis of about three to five feet and a diameter of about five inches, the body comprising a shroud at a rear end of the body which includes a propeller, elevators, rudders, and static hydrodynamic fins; actuators for controlling the elevators and the rudders; a shaft coupled at one end to the propeller; an internal motor, coupled to the other end of the shaft, for applying a torque to the propeller via the shaft; an internal guidance and control subsystem for implementing a predetermined path and speed profile for the vehicle in the ocean water by controlling the motor and the actuators to cause the vehicle to conform to the path and speed profile, the guidance and control subsystem controlling the motor to increase or decrease the torque applied to the propeller to increase or decrease the speed of the vehicle in the ocean water from a first speed to a second speed thereby creating a moment which tends to cause the vehicle to roll about the longitudinal axis as a function of speed, the static hydrodynamic fins counterbalancing the increased or decreased torque as a function of speed to substantially prevent any roll of the vehicle; an internal signal processing subsystem for simulating a submarine by generating signals representative of the submarine and causing corresponding acoustic signals to be transmitted into the ocean water; and an internal power source for powering the signal processing subsystem, the guidance and control subsystem, the motor, and the actuators.