USCG Exam PracticeBoiler and steam propulsion fundamentals
What type of boiler construction is standard in modern marine propulsion plants, and what is its principal structural characteristic?
- A. Fire-tube (Scotch) boiler, in which hot combustion gases pass through tubes surrounded by a large drum of water
- ✓ Water-tube boiler, in which water and steam are inside the tubes and hot combustion gases pass over the outsideCorrect
- C. Electric boiler, in which heating elements immersed in the water drum generate steam without combustion
- D. Exhaust gas boiler, in which engine exhaust gases pass through tubes surrounded by feedwater
Why B is correct
Marine boilers are almost always water-tube boilers, in which the water and steam are inside the tubes and the hot combustion gases pass over the outside. Fire-tube (Scotch) boilers, where hot gas runs through tubes surrounded by a large drum of water, are the older design and are not standard in modern marine propulsion plants. (NAVEDTRA 14104 §4-1)
Cited:NAVEDTRA 14104 §4-1