Question 87Motor Plants - 1st Asst/Chief

The correct answer is C) fuel consumption varies as the cube of the shaft RPM. On a slow-speed, diesel-propelled vessel operating with constant slip, the fuel consumption varies as the cube of the shaft RPM. This is because the power required to propel the vessel is proportional to the cube of the shaft speed, and the fuel consumption is directly proportional to the power required. The other options are incorrect because: A) Fuel consumption does not vary as the square of the shaft RPM, as this would not accurately represent the relationship between power and shaft speed. B) Fuel consumption does not vary directly proportional to the shaft RPM, as this would not account for the effect of the cube relationship between power and shaft speed. D) Fuel consumption does not vary inversely with the shaft RPM, as this would be the opposite of the correct relationship.