, 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.


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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. Hudson

You have 600 tons of below deck tonnage. There is no liquid mud aboard. If you have 150 tons of cargo above deck with a VCG above the deck of 2.8 feet, what is the maximum allowed VCG of the remainder of the deck cargo that is permitted? (See illustration D036DG, stability letter for M.V. Hudson)

A. 1.96 feet  Incorrect.

B. 2.25 feet  Incorrect.

C. 3.20 feet  Correct.

D. 3.55 feet  Incorrect.


 M.V. Hudson stability letter and Loading Diagram click to view D036DG

1. Important information found in the stem of the question:

a. No liquid mud onboard

b. 600 tons of below deck tonnage.

Taking these two variables you would consult the Loading Diagram, found on the third page in Diagram D036DG, to find the MAXIMUM amount of cargo allowed above deck.

On the horizontal grid find 600 tons of below deck tonnage and run vertically until you intersect with the line labeled "WITHOUT LIQUID MUD". From this point run horizontally to find the "ABOVE DECK CARGO", which is 300 Long Tons.

2. Looking at the first page of Diagram D036DG in paragraph #3 you will find that "the height above the main deck of the center of gravity of the deck cargo shall not exceed the value shown on the LOADING DIAGRAM (3.0 feet)."

To find VCG of Remaining Deck Cargo :

VCG = Vert. Moment / Total Weight

3.0 feet = (420 + 150X) ft-tons / 300 Tons

150X ft-tons = 480 Tons

X = 3.2 feet


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Revised: 16 May 2020 18:01:08 -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