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Master or Mate < 200 GRT Rivers, Revision & Practice Exams

Master or Mate < 200 GRT Rivers. Built from official USCG NMC sample examinations (public domain).
Content last updated 12 June 2026

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The real exam is passed module by module: Rules of the Road requires 90%, most other modules 70%. Chart-plotting modules are taken on paper and not included.

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Frequently asked questions

What score do I need to pass the Master or Mate < 200 GRT Rivers exam?

You must pass each module separately. Most modules require 70% to pass.

What modules are on the Master or Mate < 200 GRT Rivers exam?

The exam covers 2 modules: Deck General – Safety, Navigation General – Rivers.

How many practice questions are available for Master or Mate < 200 GRT Rivers?

This page includes free sample questions drawn from the official USCG sample examinations, with a full bank of around 116 questions across all modules available with lifetime access.

Are these real USCG exam questions?

Every question comes from the U.S. Coast Guard National Maritime Center's published sample examinations, which are U.S. government works in the public domain. Wheelhouse Prep is not affiliated with or endorsed by the U.S. Coast Guard.

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No. The free practice tests work in your browser with no signup. Your score history is saved on your own device.

Sample Master or Mate < 200 GRT Rivers practice questions

A selection of free questions from the official USCG sample examinations. Use the interactive modules above for timed, scored drills.

Which is the BEST way to reduce your wake in a narrow channel?

  1. Reduce your speed ✓
  2. Change your course to a zigzag course
  3. Apply enough rudder to counter the effect of the current
  4. Shift the weight to the stern

A fire in electrical equipment should be extinguished by using which type of extinguishing agent?

  1. CO2 ✓
  2. Salt water
  3. Foam
  4. Low-velocity fog

A situation has occurred where it becomes necessary for you to be towed. What action should be taken to prevent your vessel from yawing?

  1. Shift weight to the center of the boat
  2. Shift weight to the bow
  3. Throw excess weight overboard
  4. Shift weight to the stern ✓

Why: Shifting weight aft sets the stern deeper, increasing drag aft so the towed vessel trails straight behind the towline like a weathervane instead of sheering from side to side.

Show all 20 sample questions with answers & explanations

How are chart legends which indicate a conspicuous landmark printed?

  1. In italics
  2. With underlined letters
  3. In boldfaced print
  4. In capital letters ✓

Which is TRUE as the temperature of the air reaches the dew point?

  1. Fog may form ✓
  2. Rain must develop
  3. It begins to snow
  4. Water freezes

Your vessel is on course 150°T, speed 17 knots. The apparent wind is from 40° off the starboard bow, speed 15 knots. What is the speed of the true wind?

  1. 9.0 knots
  2. 10.2 knots
  3. 11.0 knots ✓
  4. 12.0 knots

As a warm front approaches how does barometric pressure change?

  1. Pressure falls ✓
  2. Pressure is steady
  3. Pressure rises
  4. Pressure is uncertain

Which of the signals listed is required to be displayed at night while bunkering at a dock?

  1. One red light over a white light
  2. Two red lights
  3. One red light ✓
  4. One red light over a yellow light

What can be done to prevent small oil spills on deck from going overboard?

  1. Plugging the sounding pipes
  2. Plugging the drains and scuppers ✓
  3. Closing the lids on the vents
  4. Driving wooden plugs into the vents

Which U.S. agency assigns an official number to a vessel?

  1. Collector of Customs
  2. Treasury Department
  3. Coast Guard ✓
  4. American Bureau of Shipping

Why: Official numbers for documented U.S. vessels are assigned by the Coast Guard through the National Vessel Documentation Center. ABS is a classification society, and Customs no longer handles vessel documentation.

There is a fire in the crew's quarters of your vessel. Which action should you take FIRST?

  1. Ventilate the quarters as much as possible
  2. Close all ventilation to the quarters if possible ✓
  3. Prepare to abandon ship
  4. Attempt to put the fire out yourself before sounding the alarm

What is the purpose of a striking plate?

  1. It provides a surface for applying force on machinery
  2. It prevents valve stem over-travel
  3. It provides a landing surface for the sounding bob ✓
  4. It absorbs machinery vibration

Safe water buoys may show ONLY which type of light?

  1. flashing green lights
  2. yellow lights
  3. white lights ✓
  4. flashing red lights

Which term describes a light, feathery deposit of ice by sublimation of water vapor directly into the crystalline form on objects whose temperatures are below freezing?

  1. Snow
  2. Frost ✓
  3. Glaze
  4. Dew

A green buoy has a yellow triangle on it. What type of buoy is this?

  1. It is a dual-purpose marker used where the ICW and other waterways coincide ✓
  2. This is an information or regulatory buoy that has lateral significance
  3. It is a buoy that was set in error and will be replaced with a red nun buoy
  4. This buoy that is off-station and is marked to warn mariners of its wrong position

On an isomagnetic chart, which term is used for the line of zero variation?

  1. An agonic line ✓
  2. An isogonic line
  3. The zero-variation line
  4. A variation line

Buoys which mark dredging areas are painted which color?

  1. Black
  2. Green
  3. Red
  4. Yellow ✓

To find the specific phase characteristic of a lighthouse on a sound of the United States you would use which reference?

  1. U.S. Coast Pilot
  2. Nautical Chart Catalog
  3. American Practical Navigator
  4. Light List ✓

Why: The Light List gives each light's complete characteristic, including rhythm, period, and colors, in more detail than the chart abbreviation. The Coast Pilot describes waters generally but is not the reference for light characteristics.

As a general rule, how will your vessel lie when it is drifting in a locale where there is no current?

  1. The bow to the wind
  2. With the wind on the quarter
  3. The beam to the wind ✓
  4. The stern to the wind

Which action should be taken prior to assuming the Deck Watch while the vessel is in port?

  1. Make a security call on VHF channel 16
  2. Ensure that the vessel's moorings are adequate ✓
  3. Ensure that all crew members are onboard
  4. Visually inspect and test operation of the blue mooring light

Why: In port the moorings are the vessel's primary safety concern; tide, current, and cargo operations constantly change line tension. The relieving watch officer must verify moorings are adequate before accepting responsibility. There is no such thing as a blue mooring light.