USCG Exam PracticeLube oil and fuel oil systems
A marine diesel's fuel-oil system uses duplex filters between the service tank and the injection equipment. What is the primary operational reason for this duplex arrangement?
- A. To increase fuel pressure to the injectors during heavy load conditions
- ✓ To allow one filter to be cleaned while the other remains in service, maintaining uninterrupted fuel flowCorrect
- C. To separate water from the fuel before it reaches the injection plungers
- D. To reduce fuel viscosity by increasing flow velocity through the filter media
Why B is correct
NAVEDTRA 14075 §3-2 describes duplex filters as being arranged so one can be cleaned while the other stays in service, ensuring continuous fuel delivery to the injection equipment. Water separation is performed by a dedicated water separator, not the duplex filters.
Cited:NAVEDTRA 14075 §3-2