, 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.

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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



Sample Solution for Vertical Center of Gravity (VCG) problem M.V. Surveyor

You have 6 containers of ship stores each measuring 8'L by 4'B by 6'H and weighing 0.5 ton each. Each container is stowed on deck. What is the maximum VCG permitted of the remaining cargo if you are carrying rig water and load to maximum capacity? (See illustration D037DG, stability letter for M.V. Surveyor)

A. 1.06 feet (Incorrect)  B. 1.32 feet (Incorrect) C. 1.65 feet (Incorrect) D. 1.90 feet (Correct)


M/V Surveyor's Stability Letter  click to view

1) Paragraph 4. states that if you carry rig water, which according to the question you are, then the maximum weight of cargo without other below deck cargo or ballast is 35 tons.

2) Paragraph 3. states that the height above the main deck of the center of gravity of deck cargo shall not exceed 2.0 feet.

Therefore, according to paragraphs 3 and 4 the moment for maximum deck cargo load with a vessel carrying rig water is 70 foot-tons (35 tons x 2.0 feet).

The moment for the containers is 3.0 tons x 3.0' = 9 foot-tons.

3.0 tons = 6 containers x 0.5 tons each

3.0 feet = the height of each container is 6 feet. The vertical center of gravity of each

container is 3.0 feet.

Remaining Cargo = Max Load - Containers

VCG = Moment/Tons

VCG = 61 foot-tons/ 32 tons

VCG = 1.9   

Answer D. 1.90 feet (Correct)




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Revised: 16 May 2020 18:00:50 -0400 

Contact Phone: 207-629-7004

Email: Captain Steve 

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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