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

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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 righting moment problem

Use the following Stability Data Reference Book pages for information on the Cargo Ship S.S. American Mariner or the Tank Ship S.S. Northland to determine the correct answers to some of the stability problems.

Download Blue pages        Download White pages       Download Salmon pages


Your vessel's drafts are: FWD 17'-05", AFT 20'-01"; and the KG is 22.4 feet. What is the righting moment when the vessel is inclined to 15˚ ? (Use the reference material in Section 1, the blue pages, of the Stability Data Reference Book)

A. 10,656 foot-tons (Correct)  B. 12,340 foot-tons (Incorrect) C. 13,980 foot-tons (Incorrect) D. 17,520 foot-tons (Incorrect)

Step 1:

Find Mean Draft.

Fwd Draft 17'-05" + Aft Draft 20'-01" = 37'-06"

Mean Draft = 37'-06"/2

Mean Draft = 18'-09"

Step 2:

Find the displacement of the vessel by using the mean draft and the Deadweight Scale (Blue Pages).

Displacement = 9450 tons


Step 3:

Find the change in the center of gravity between the actual KG and the assumed KG for the vessel..

Actual KG: 22.4'

Table KG: -20.0'

GG1:      =   2.4'

Step 4:

Find the corrected righting arm due the change in the center of gravity.

correction = GG1 x Sin Angle (angle of list)

= 2.4' x Sin 15˚

= 2.4' x .2588 (.2588 is Sin 15˚ to four decimal places. Not .25 stated in the Cross Curves.

= 0.62'

Corrected GZ = GZ -correction

*** for GZ, find the intersection of the curved line for inclination (15˚) and displacement tonnage

(9,450) in the Cross Curves (Blue Pages)

= 1.75'

 - 0.62'

= 1.13'

Step 5:

Find the righting moment.

Righting Moment = GZ x Weight (displacement)

= 1.13' x 9,450 tons

= 10,656 foot-tons    (correct answer is A)



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Revised: 16 May 2020 17:54:43 -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  

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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