196. If the speed necessary for reaching port at a designated time is 17.8 knots and the pitch of the propeller is 24.7 feet, how many revolutions per minute will the shaft have to turn, assuming a 7% positive slip?

The correct answer is 79 RPM. Converting the required speed to feet per minute and accounting for the 7% positive slip results in a shaft speed of approximately 78.5 RPM, making 79 RPM the closest and therefore correct answer.