, Training for Mariners. The First with Online Study for the Maritime Industry.

  Welcome to Established in 1996, we are the ultimate source for online USCG exam preparation assistance. provides free online exam preparation along with downloadable studyguides and standalone software that allows you to continue your studies without an internet connection.


Prepare for or supplement your studies for your USCG license exam here.

Click here to create an account and enter SeaSources new online study.


Hi! We have a new website! It's phone / tablet friendly and speedier. Please visit it today! 

The subjects listed below are currently available for testing in the new online study room and are available for download to your computer. Click on subject below for details.

Engineering Examination Questions

All Engine Room Questions

Engine Room Electrical         

Engine Room General          

Engine Room Safety            

Engine Room Steam            

Engine Room Motor   

QMED Oiler          

Deck Examination Questions

Master 25/50/100 Ton

Operator Uninspected Passenger Vessel

All Deck Questions

Able Seaman Questions

Advanced Subjects, Unlimited Oceans Master, Mate

Rules of the Road  

Aids to Navigation  Glossary Included

Breathing Apparatus

Cargo Equipment 

Cargo Stowage

Charts and Publications 

Chemical Testing

Right Whales

Damage Control  

Deck Engineering

Deck Safety

Emergency Procedures 

FCC Exam Questions

Fire Fighting Glossary Included 

First Aid  


Great Lakes

Hazardous Cargo

Inert Gas

Inland Navigation  

Instruments and Accessories



Liquid Cargo and Bunkering

Marine Radio Operator 

Meteorology  "Glossary Included" 

Mobile Offshore Drilling Unit

Latest NMC / USCG Questions

Celestial Navigation

Navigational Procedures

Pollution Control and Prevention

Rules and Regulations

Plotting/Navigational Problems


Survival Craft

Seamanship   Glossary Included

Sailing Vessels  

Ship Handling 

Ships Construction Glossary Included  

Ships Business


Stability and Trim Glossary Included 


Tides and Currents Glossary Included 



Common Knots

Radar Plotting



Motor Plants

Preview Motor I Questions

Preview Motor II Questions


 Listed below is a table of contents of the questions on this subject as they appear in the new online study. Click on the "Enter Online Study" link above to begin preparing for your exam.

From the pull down menu in the online study select from the following topics:

All USCG Engine Room Question Databank

  • Motor Plants
    • Cooling Systems   
      •  Components 
        • Distillers-jkt. Wtr. Heated and Other Controls
        • Expansion Tanks
        • Heat Exchangers
        • Pumps
        • Temperature Control and Systems
      •  Maintenance
        • Distillers- Jkt. Wtr. Heated
        • Water Treatment
      •  Troubleshooting Watchstanding
        • Cavitation
        • Cracked Heads
        • Distillers-jacket
        • Water Heated
        • Pressure Fluctuations_ Fouling
        • Water Temperature
    • Fuel Oil and Combustion
      •  Fuel Oil Management
        • Cleaning Tanks
        • Fuel Oil Management
        • Transfer
      • Principles Of Combustion
        • Atomization
        Combustion Cycle
        • Energy Cells and Pre-combustion Chambers
        • Heat Of Compression
        • Ignition Delay
        • Injection
        • Injection Lag
    • Fuel Systems
      • Components
        • Booster Pumps
        • Fuel Oil Centrifuging and Filtering
        • Fuel Pumps
        • Injectors
        • Piping
        • Maintenance
        • Fuel Pump Maintenance
        • Nozzle Testing
      • Troubleshooting Watchstanding
        • Centrifuge Troubleshooting
        • Injection Pumps
        • Injectors
        • Poor Combustion
    • Intake and Exhaust Systems
      • Troubleshooting Watchstanding
        • Exhaust System Problems
    • Lubrication Systems
      • Components: Operation and Function
        • Bearing Lubrication
        • Before and After Starting
        • Cylinder Lubricators and Pumps
        • Diesel Engine Lube Oil Systems
        • Lube Oil Coolers
        • Mist Detection and Monitoring
        • Piston and Piston Ring Lubrication
        • Strainer Types
        • Types Of Systems
      • Maintenance
        • L. O. Dilution
        • Metal Edge Strainer
        • Testing Of Lube Oils
      • Troubleshooting Watchstanding
        • Color Of Oils and Pressure Relations
        • Contamination
        • Fuel Oil Dilution
        • High Consumption
        • Lube Oil Control Rings
    • Main Engine: Large Slow Speed
      • Components: Operation and Function
        • Bearings
        • Cams and Camshafts
        • Construction
        • Cycle and Efficiency
        • Direct Reversing
        • General Operation
        • Math (displ., Compr. Ratio, Mep, Horsepower, Etc.)
        • P_V Diagrams
        • Piston Rods and Connecting Rods
        • Pistons: General
        • Valves and Timing
      • Maintenance
        • Bearings
        • Crankshafts
      • Troubleshooting Watchstanding
        • Bearings
        • Low Compression
        • Overload-firing Press.
        • Securing One Cylinder Etc.
        • Ring & Liner Wear
    • Medium and High Speed Engines
      • Components: Operation and Function
        • Bearings
        • Camshafts
        • Connecting Rods and Crankshafts
        • Cylinders and Cylinder Head
        • Intake Valves
        • Math (displ., Compr, Ratio, Mep, Horsepower, Etc.)
        • Parts
        • Pistons
      • Maintenance
        • Bearings
        • Piston Rings
        • Valves and Timing
      • Troubleshooting Watchstanding
        • Bearings
        • Cylinders, Pistons, and Rings
        • Starting and Stopping
        • Valves
    • Miscellaneous  Maintenance
      • Watch Duties:
        • Motor Plants
    • New Questions
      • Un Categorized 
        • All Sub Topics
    • Starting Systems
      • Components: Operation and Function
        • Air Starting Systems - Large Low Speed
        • Bendix Clutch
        • Electric Starting Systems
        • Fluid Type Starting Systems
        • Reversing
        • Stopping
      • Maintenance
        • Air Systems
        • Hydraulic Systems
      • Troubleshooting Watchstanding
        • Failure To Start
        • Leaky Air Valves
        • Starter Drive Failure
    • Auxiliary_ Waste Heat Boilers
      • Components
        • Aux Boiler Fuel Systems
        • Aux Boiler Purpose of  Refractory
        • Aux Boiler Tube Sheets
        • Aux Boiler Tubes Etc.
        • Classification and Construction
        • Feed Systems
        • Pressure Control Devices
        • Safety Valves
        • Steam-water System
        • Waste Heat Boilers
      • Maintenance
        • Aux Boiler Controls
        • Aux Boiler Gage Glass
        • Aux Boiler Hydrostatic Test
        • Aux Boiler Tube Repair
        • Burners
        • Scale Deposits and Water Treatment
      • Troubleshooting Watchstanding
        • Aux Boiler Combustion Problems
        • Aux Boiler Tube Rupture
        • Distorted Furnaces
        • Safety Valve Problems
    • Distilling Systems
      • Troubleshooting Watchstanding
        • Leaks
    • Drive Systems
      • Components: Operation and Function
        • Couplings: General
        • Reduction Gear Bearing
        • Reduction Gear Types
        • Thrust Bearings
      • Maintenance
        • Misalignment
      • Troubleshooting Watchstanding
        • Clutches
        • Gear Scoring and Pitting
        • Vibrations
    • Governors and Control Systems
      • Components: Operation and Function
        • Compensating Needle Valve
        • Components
        • Control Systems
        • Definitions
        • Isochronous
      • Maintenance
        • Oil Changes
      • Troubleshooting Watchstanding
        • Air Bubbles
        • Hunting
        • Restarting
        • Speeder Spring
    • Intake and Exhaust Systems
      • Components: Operation and Function
        • Exhausts Systems
        • Intake Components
        • Port Opening and Closing and Timing
        • Pyrometers
        • Valves: General
      • Maintenance
        • Manifolds
        • Pyrometers
      • Troubleshooting Watchstanding
        • Exhaust System Problems
        • Improper Valve Lash
        • Intake System Problems
        • Smoke Color: General
        • Worn Valve Guides_ Carbon Deposits
    • Main Engine: Large Slow Speed
      • Components: Operation and Function 
        • P V Diagrams
      • Maintenance
        • Bearings
        • Regulations
        • Watch Duties: Motor Plants
    • Petroleum Product Principles
      • Petroleum Liquid Tests
        • Neutralization Number
    • Ship Construction and Repair
      • Propellers
    • Turbo Charging and Scavenging Systems
      • Components: Operation and Function
        • After cooler Operation
        • Blower Pressure
        • Effect Of Increased, decreased Load
        • Pulse-constant
        • Purpose
        • Roots Blowers
        • Scavenging
        • Speed Variation
        • Turbocharger Const
        • Valve Overlap
      • Turbo Charging and Scavenging Systems
        • Maintenance
          • Turbocharger Maintenance
        • Troubleshooting Watchstanding
          • Air Temp
          • Over speeding
          • Turbocharger Failure
          • Vibrations
        • Watch Duties
          • Troubleshooting Watchstanding

  If you are studying for a United States Coast Guard Engine Room License exam which includes this module, you should  work through these questions until you are scoring 80% or better on them.

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Revised: 12 May 2020 18:25:20 -0400 

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For details on license requirements, application forms,  licensing fees, and testing locations, visit the United States Coast Guard / National Maritime Centers web site and look under Mariner's information center. The questions used in the online study are once again available to the public in PDF format from the NMC link above. The illustrations are not yet available for some of these questions.

Vessel Nomenclature  

View Screenshots of "TesTTaker" Software  

View Screenshots/Tutorial of Online Study

View comments from SeaSources Members 

See also:

SeaSources online Celestial Navigation Course 

MARYLAND NAUTICAL  Great source for practice charts and study guides


National Oceanic & Atmospheric Administration (NOAA)

The Navigation Center

Chart No. 1 Nautical Chart Symbols Abbreviations and Terms

Bluewater Books and Charts 

Search CFR'S Online

Open Book Renewals

Required Subjects for all Deck Licenses

Required Subjects for all Engineering Licenses

Required Subjects for Mobile Offshore Drilling Units, MODU.

Sea Service Requirements for Coast Guard Licenses