Question 107Steam Plants - 1st Asst/Chief

The correct answer is B) positive displacement rotary pumps. Positive displacement rotary pumps are commonly used for fuel oil service on vessels because they are well-suited for pumping viscous liquids like fuel oil. These pumps create a constant flow by trapping a fixed volume of liquid and forcing it through the discharge line. This makes them reliable and efficient for handling fuels, which is a critical safety requirement for fuel oil systems. The other answer choices are not as suitable for fuel oil service. Explosion-proof gear pumps may be used, but are not the normal choice. Nonvented plunger pumps and two-stage centrifugal pumps are not typically utilized for fuel oil service on vessels.