🔍 Key Concepts

• Basic purpose and construction of diesel exhaust mufflers on vessels • Difference between moving parts and fixed baffles/chambers in a muffler • What types of hazards (fire, dust, sparks) mufflers are intended or NOT intended to handle

💭 Think About

• Think about the main job of any exhaust muffler on a diesel engine. What do they always need to do, whether wet or dry? • Ask yourself which option sounds unrealistic for any piece of machinery on a boat over time, especially in a hot, sooty exhaust stream. • Consider which options describe features that would be special add‑ons rather than basic, universal characteristics.

✅ Before You Answer

• Check which choices would clearly be false for at least one type (wet or dry) of exhaust system. • Ask: Does this feature usually require extra design or certification (like a true spark arrester) beyond a normal muffler? • Eliminate any option that would imply no wear, no inspection, or no cleaning on exhaust equipment exposed to heat, soot, and water.