USCG General Engineering 2 — Questions and Answers
Question 1: What is the primary purpose of a diesel engine's intercooler?
- To cool the engine block
- To cool compressed intake air before it enters the cylinder (Correct answer)
- To reduce exhaust gas temperature
- To cool engine lubricating oil
Correct answer: To cool compressed intake air before it enters the cylinder
An intercooler cools compressed air from the turbocharger before it enters the cylinder, increasing air density and allowing more fuel to burn efficiently.
Question 2: On a marine vessel, what type of pump is most commonly used for bilge pumping operations?
- Centrifugal pump (Correct answer)
- Reciprocating pump
- Gear pump
- Rotary vane pump
Correct answer: Centrifugal pump
Centrifugal pumps are most commonly used for bilge service due to their ability to handle large volumes of water and their self-priming capability when fitted with a foot valve.
Question 3: What is the function of a sea chest in a ship's cooling water system?
- To store emergency freshwater
- To provide a protected intake for seawater used in cooling systems (Correct answer)
- To separate air from cooling water
- To filter fuel oil before combustion
Correct answer: To provide a protected intake for seawater used in cooling systems
A sea chest is a hull fitting with a strainer that provides a protected seawater intake point for the ship's cooling and other seawater systems.
Question 4: When checking a diesel engine's injection timing, which instrument is typically used?
- Manometer
- Pyrometer
- Timing light or dial gauge on the flywheel (Correct answer)
- Viscometer
Correct answer: Timing light or dial gauge on the flywheel
Injection timing on a diesel engine is checked using a timing light or a dial gauge referenced to degree markings on the flywheel.
Question 5: What does the term 'MARPOL' refer to in marine engineering?
- Marine Pollution Prevention Regulations (Correct answer)
- Marine Propulsion and Operations Log
- Maritime Patrol and Operations Legislation
- Marine Port Authorization Log
Correct answer: Marine Pollution Prevention Regulations
MARPOL stands for the International Convention for the Prevention of Pollution from Ships, governing discharge of oil, sewage, garbage, and other pollutants.
Question 6: In a ship's electrical system, what is the purpose of a bus bar?
- To supply power to the propulsion shaft
- To serve as a common conductor connecting multiple circuits (Correct answer)
- To step up voltage from generators
- To isolate faulty circuits from the system
Correct answer: To serve as a common conductor connecting multiple circuits
A bus bar is a metallic conductor that acts as a common connection point distributing electrical power from generators to various shipboard circuits.
Question 7: What causes diesel engine 'knock' during operation?
- Excessive lubrication oil pressure
- Ignition delay causing a large amount of fuel to ignite simultaneously (Correct answer)
- Low fuel viscosity
- High coolant temperature
Correct answer: Ignition delay causing a large amount of fuel to ignite simultaneously
Diesel knock is caused by ignition delay — fuel accumulates in the cylinder before combustion starts, then all ignites at once, causing a rapid pressure rise and audible knock.
USCG General Engineering 2
What is the primary purpose of a diesel engine's intercooler?