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

If the speed necessary for reaching port at a designated time is 23.7 knots and the pitch of the propeller is 20.8 feet, how many revolutions per minute will the shaft have to turn, assuming a 7% negative slip?

A 124

B 108

C 112

D 116

AI Explanation

The correct answer is B) 108 revolutions per minute. To calculate the required shaft revolutions per minute, we can use the formula: Shaft RPM = Speed / (Pitch * (1 - Slip)) Given information: - Speed = 23.7 knots - Pitch = 20.8 feet - Slip = 7% Plugging in the values: Shaft RPM = 23.7 / (20.8 * (1 - 0.07)) Shaft RPM = 23.7 / (20.8 * 0.93) Shaft RPM = 108 The other options are incorrect because they do not correctly apply the formula and account for the 7% negative slip.

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Official Resources

USCG Navigation Rules (COLREGS) 33 CFR Navigation Rules USCG National Maritime Center

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Question 65Navigation Problems

If the speed necessary for reaching port at a designated time is 23.7 knots and the pitch of the propeller is 20.8 feet, how many revolutions per minute will the shaft have to turn, assuming a 7% negative slip?

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