USCG Exam PracticeBoiler and steam propulsion fundamentals
Under 46 CFR §56.50-30, feed pumps for water-tube boilers are restricted regarding their water supply connections. A vessel's chief engineer proposes connecting a water-tube boiler feed pump to both the freshwater system and the saltwater fire main as a backup supply. Which statement correctly evaluates this proposal?
- A. The proposal is acceptable provided a stop-check valve is fitted between the saltwater connection and the pump suction
- ✓ The proposal is not permitted; 46 CFR §56.50-30(a)(4) requires feed pumps for water-tube boilers to have freshwater connections onlyCorrect
- C. The proposal is acceptable because 46 CFR §56.50-30 requires two separate means of feedwater supply, and the saltwater connection satisfies the second means
- D. The proposal is acceptable only if the saltwater connection is used exclusively as an emergency measure and is documented in the vessel's SMS
Why B is correct
46 CFR §56.50-30(a)(4) explicitly states that feed pumps for water-tube boilers must have freshwater connections only. Connecting a saltwater supply to a water-tube boiler feed pump is prohibited regardless of valve arrangements, emergency intent, or SMS documentation. Saltwater would introduce chlorides and cause severe scaling and corrosion. (46 CFR §56.50-30)
Cited:46 CFR §56.50-30