If both the shell-and-tube lube oil cooler and shell-and-tube jacket water cooler of a diesel engine are seawater cooled, what statement is true?

Correct Answer: Option C — Seawater flows through the tubes of both the lube-oil and jacket-water coolers.

Seawater is highly corrosive and typically restricted to the tube side of shell-and-tube exchangers to protect the shell and simplify maintenance. By routing seawater through the tubes of both coolers, the shell side remains available for the process fluids, minimizing the risk of seawater contamination in lube oil or jacket water.