What is the minimum diameter allowed for bilge piping on small passenger vessels which are more than 65 feet in length?

Correct Answer: Option B — 1-1/2"

46 CFR 182.520 specifies the minimum requirements for bilge piping systems. For small passenger vessels exceeding 65 feet in length, the regulations mandate a minimum internal diameter of 1-1/2 inches for bilge piping to ensure sufficient capacity for effective dewatering during emergency or routine bilge pumping operations.