🔍 Key Concepts

• 46 CFR Part 63 – Automatic Auxiliary Boilers and related boiler automation rules • The difference between mechanical/mercury-type controls and more modern electronic or pneumatic control systems • Why certain types of devices may be considered unsafe on vessel boilers subject to vibration, shock, and listing

💭 Think About

• Think about which device type is most sensitive to ship motion, vibration, and temperature changes and could fail in a seaway. • Ask yourself which of these devices the Coast Guard would be most likely to phase out due to breakage risk or leaking hazardous substances. • Consider which devices are specifically mentioned in 46 CFR as not acceptable for safety‑critical boiler control functions on ships.

✅ Before You Answer

• Verify in 46 CFR Part 63 (especially sections on controls and safety devices) which control technologies are permitted or encouraged. • Check whether mercury-based devices have any special restrictions in marine service due to potential failure modes or environmental concerns. • Confirm which of the listed devices are commonly used today on modern automatic auxiliary boilers (those are less likely to be prohibited).