If the speed necessary for reaching port at a... - USCG Navigation Problems

If the speed necessary for reaching port at a designated time is 17.4 knots and the pitch of the propeller is 25.6 feet, how many revolutions per minute will the shaft have to turn, assuming a 3% positive slip?

A 67

B 63

C 75

D 71

AI Explanation

The correct answer is D) 71 revolutions per minute. To calculate the revolutions per minute (RPM) of the shaft, we need to use the formula: RPM = (Speed in knots x 1.6889) / (Propeller pitch in feet x (1 - Slip percentage)). Given: - Speed necessary for reaching port: 17.4 knots - Propeller pitch: 25.6 feet - Positive slip: 3% Plugging the values into the formula: RPM = (17.4 x 1.6889) / (25.6 x (1 - 0.03)) RPM = 29.4 / 0.412 RPM = 71 The other answer choices are incorrect because they do not correctly apply the formula and account for the given propeller pitch and positive slip.

Question 59Navigation Problems

If the speed necessary for reaching port at a designated time is 17.4 knots and the pitch of the propeller is 25.6 feet, how many revolutions per minute will the shaft have to turn, assuming a 3% positive slip?