Wheelhouse Prep USCG Mariner Exam Prep

Able Seafarer Unlimited, Limited, Special,, Revision & Practice Exams

Able Seafarer Unlimited, Limited, Special,. Built from official USCG NMC sample examinations (public domain).
Content last updated 12 June 2026

Revision Mode

Revise with instant feedback: the moment you pick an answer you see whether it was right, with the explanation where available. Untimed — ideal before you sit a mock exam. Questions you miss keep coming back until you know them.

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Exam Mode

Exam-day conditions: no feedback until you submit, each module scored separately so you can see your weak areas, plus an overall score against the pass mark, with a full question-by-question review at the end.

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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.

Modules & your progress

Unlock the full question bank

The free sample is 25 questions, spread across every module in the same proportions as the real exam. The full bank contains every question from the NMC's current published sample examinations for this credential, with written explanations on the popular small-vessel credentials, one-off $29, lifetime access on up to 3 devices, all credentials included.

Buy lifetime access, $29

Score history

The real exam: key facts

Delivered byUS Coast Guard National Maritime Center; exams are sat at Coast Guard Regional Exam Centers (RECs)
Official examMerchant Mariner Credential (MMC) endorsement examinations
QuestionsSet per credential in your Approval to Test letter; the NMC does not publish module question counts
TimeEach module is sat in a 3½-hour examination period; modules are taken in consecutive periods
Passing scoreRules of the Road 90%; Deck General and Deck Safety 70% (NMC notice, January 2018)
Exam feeSet by 46 CFR 10.219: for an original officer endorsement, evaluation $100, examination $95 (lower level) or $110 (upper level), issuance $45
Pre-licensing or eligibilityApply to the Coast Guard first; you need the NMC's Approval to Test letter before you can book. The application stays valid for 12 months
Book your examdco.uscg.mil/nmc/Examinations

Checked 11 October 2026 from the official sources below. Rules and fees change, so confirm with US Coast Guard National Maritime Center; exams are sat at Coast Guard Regional Exam Centers (RECs) before you book.

Official sources

How Wheelhouse Prep compares

Wheelhouse is a $29 question bank built from the Coast Guard's own sample exams, not an approved course. Here is how it compares with the courses and tools mariners usually consider, including where they are the better choice. See the comparison with Mariners Learning System, Sea School, MPT and others.

Frequently asked questions

What score do I need to pass the Able Seafarer Unlimited, Limited, Special, exam?

You must pass each module separately. Rules of the Road requires 90%; most other modules require 70%. Chart-plotting modules are worked on paper.

What modules are on the Able Seafarer Unlimited, Limited, Special, exam?

The exam covers 2 modules: Navigation General – Rules of the Road, Deck General – Safety.

How many practice questions are available for Able Seafarer Unlimited, Limited, Special,?

This page includes free sample questions drawn from the official USCG sample examinations, with a full bank of around 89 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.

Do I need to create an account?

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

When were these Able Seafarer Unlimited, Limited, Special, questions last updated?

Last updated 12 June 2026. The bank is refreshed whenever the Coast Guard publishes revised sample examinations.

Sample Able Seafarer Unlimited, Limited, Special, practice questions

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

INLAND ONLY You are underway in a narrow channel, and are being overtaken by another power-driven vessel. The overtaking vessel sounds the signal indicating his intention to pass you on your starboard side. What is your signal of agreement?

  1. one short blast ✓
  2. one prolonged, one short, one prolonged, and one short blast in that order
  3. two prolonged blasts
  4. two prolonged followed by two short blasts

BOTH INTERNATIONAL & INLAND A vessel nearing a bend where other vessels may be obscured is required to sound which signal?

  1. One short blast
  2. One prolonged blast ✓
  3. Two short blasts
  4. One long blast

What is the cause of most minor spills of oil products?

  1. Human error ✓
  2. Equipment failure
  3. Major casualties
  4. Unforeseeable circumstances
Show all 25 sample questions with answers

What does the helm command "shift the rudder" mean?

  1. Shift the rudder control to the alternate steering method.
  2. Put the rudder over to the opposite side, the same number of degrees it is now. ✓
  3. Stop the swing of the ship.
  4. Put the rudder amidships and hold the heading steady as she goes.

Which would be considered pollution under the U.S. water pollution laws?

  1. Oil
  2. Hazardous substances
  3. Garbage
  4. All of the above ✓

Geographic range is the maximum distance at which a light may be seen under which conditions?

  1. Existing visibility conditions, limited only by the intensity of the light
  2. Permitting visibility conditions, limited only by interference from background lighting
  3. Permitting visibility conditions, limited only by the curvature of the Earth ✓
  4. Existing visibility conditions, limited only by the curvature of the Earth

When the handle of an all-purpose nozzle is pulled all the way back, it will __________.

  1. produce low-velocity fog
  2. produce high-velocity fog
  3. produce a straight stream ✓
  4. shut off the water

How are buoys which mark isolated dangers painted?

  1. Alternating green and black bands
  2. Alternating red and black bands ✓
  3. Alternating green and white bands
  4. Alternating red and white stripes

What is an advantage of the magnetic compass aboard vessels?

  1. It is reliable due to its essential simplicity. ✓
  2. All points on the compass rose are readily visible.
  3. Compass error is negligible at or near the earth's magnetic poles.
  4. It does not have to be checked as often.

Which is TRUE concerning compass error?

  1. Compass error is the difference between true and magnetic heading
  2. Compass error is variation plus compass course
  3. Compass error is the sum of variation and deviation ✓
  4. Compass error is equal to deviation minus variation

You have a large, broken-down vessel in tow with a wire rope and anchor cable towline. Both vessels have made provision for slipping the tow in an emergency; however, unless there are special circumstances which is TRUE?

  1. The towing vessel should slip first ✓
  2. The vessel towed should slip first
  3. They should slip simultaneously
  4. Either vessel may slip first

What is the normal percentage of oxygen in air?

  1. 16%
  2. 18%
  3. 21% ✓
  4. 25%

Which buoy may be odd numbered?

  1. A spherical buoy
  2. An unlighted can buoy ✓
  3. A red buoy
  4. A yellow buoy

BOTH INTERNATIONAL & INLAND Which signal, other than a distress signal, can be used by a vessel to attract attention?

  1. Orange smoke signal
  2. Flames from a burning barrel
  3. Searchlight beam ✓
  4. Continuous sounding of a fog signal apparatus

BOTH INTERNATIONAL & INLAND When a vessel signals her distress by means of a gun or other explosive signal, which firing intervals should be used?

  1. Once an hour
  2. Once every minute ✓
  3. Once every 10 minutes
  4. Once every 3 minutes

BOTH INTERNATIONAL & INLAND What is the minimum length of vessels required to show two anchor lights?

  1. 40 meters
  2. 50 meters ✓
  3. 60 meters
  4. 70 meters

When outbound from a U.S. port, what does a buoy displaying a flashing red light indicate?

  1. The port side of the channel ✓
  2. A wreck to be left on the vessel's starboard side
  3. A sharp turn in the channel to the right
  4. A junction with the preferred channel to the left

INLAND ONLY At night, you see the lights shown in illustration D075RR below. These lights are shown by what type of vessel?

  1. barge being towed astern
  2. barge being pushed ahead
  3. tug pushing a barge ahead ✓
  4. tug towing a barge astern

Dry chemical extinguishers may be used on what class of fires?

  1. B and C only
  2. A only
  3. B only
  4. A, B or C as marked on the extinguisher ✓

What is the proper name for the fitting that allows a boom to move freely both vertically and laterally?

  1. Lizard
  2. Gooseneck ✓
  3. Spider band
  4. Swivel

While you are on watch, you learn that a crewman has not been seen on board for the past three hours. Which type of turn is best in this man-overboard situation?

  1. Scharnow ✓
  2. Round
  3. Single turn of 180°
  4. Racetrack

What is MOST important when administering artificial respiration?

  1. Clear airways ✓
  2. Use the rhythmic pressure method
  3. Know all approved methods
  4. Monitor blood pressure

Which statement is FALSE regarding the operation of a crane?

  1. The cargo block is raised and lowered by the luffing winch. ✓
  2. The cargo block is raised and lowered by the hoisting winch.
  3. The crane jib is raised and lowered by the luffing winch.
  4. None of the above

How is the Master or operator of a vessel required to keep the crew informed of the regulations concerning the discharging of garbage overboard?

  1. Have each person read and sign a copy of the regulations.
  2. Call an all hands meeting before sailing.
  3. Give each crewmember a copy of ANNEX V of MARPOL.
  4. Keep placards prominently posted. ✓

When you "end for end" a wire rope, you __________.

  1. splice two wire ropes together
  2. cut off the free end and bitter end of the rope
  3. remove the wire rope from the drum and reverse it so that the free end becomes the bitter end ✓
  4. remove the wire rope from the drum and turn it over, so the wire bends in the opposite direction