The propeller on a vessel has a diameter of...

Question 1 of 31048fy_heal_CREATE_q214_2017

The propeller on a vessel has a diameter of 23.7 feet and a pitch of 24.8 feet. What would be the apparent slip if the vessel cruised 442 miles in a 23 hour day (observed distance) at an average RPM of 89?

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Question 1 of 31048

🔍 Key Concepts

• Propeller pitch as theoretical distance advanced per revolution • How to convert RPM and time into a theoretical distance run • Formula for propeller slip % and the sign (+ or -) for apparent slip

💭 Think About

• First, find how many propeller revolutions occurred in 23 hours at 89 RPM, then how far the vessel should travel with zero slip based on pitch alone. • Compare that theoretical distance to the observed distance of 442 miles: is the vessel going farther or less than the theoretical distance? • From that comparison, determine whether the slip is positive or negative, and then what percentage it is of the theoretical distance.

✅ Before You Answer

• Be sure to convert feet to miles correctly when moving from pitch (in feet) to distance (in miles). • Check whether you are using observed distance – theoretical distance or theoretical distance – observed distance in the numerator of your slip formula, and how that affects the sign. • Verify that the sign of slip (positive vs negative) logically matches whether the vessel is traveling more or less than the theoretical pitch distance.