Question 330Motor Plants - Assistant Engineer

The correct answer is C) they are arranged to prevent gas backflow to each engine. Exhaust pipes for separate main propulsion diesel engines can be combined only when they are arranged in a way that prevents gas backflow to each engine. This is a safety requirement to ensure that the exhaust from one engine does not flow back into the other engine, which could lead to engine damage or improper operation. The other options are incorrect because: A) space limitations alone do not justify combining exhaust pipes, as the safety concern of backflow must still be addressed; B) small auxiliary engines may also require separate exhaust pipes to prevent backflow; and D) the installation of a waste heat boiler does not inherently allow for combined exhaust pipes without the necessary backflow prevention measures.