🔍 Key Concepts

• Wet-type exhaust silencers used on small diesel engines (such as lifeboat engines) • How cooling water is commonly used to reduce exhaust noise and temperature • The role of baffles or internal passages in changing gas flow to quiet the exhaust

💭 Think About

• Think about how adding water into an exhaust system would affect both the temperature and the sound of the exhaust gas flow. • Ask yourself: what kind of internal parts inside a silencer could help disrupt and slow the exhaust flow to make it quieter? • Consider whether a lifeboat diesel exhaust system is more concerned with heating the exhaust or with cooling and quieting it for safety and comfort.

✅ Before You Answer

• Check which option actually uses water as part of the silencing process, not just metal parts alone. • Verify which design would both lower exhaust temperature and reduce noise, which are key aims for lifeboat exhaust systems. • Eliminate any answer that describes the exhaust getting hotter inside the silencer, and focus on designs that involve cooling and flow disruption.