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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

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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 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.

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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

Why: Under Inland Rule 34(c), agreement in overtaking is shown by sounding the same signal the proposing vessel used, here one short blast for a starboard-side pass. The prolonged-short-prolonged-short signal is the International narrow-channel agreement.

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

Why: Rule 34(e): approaching a bend where other vessels may be obscured, sound one prolonged blast; a hidden approaching vessel answers with the same signal. Short blasts are maneuvering signals for vessels in sight.

BOTH INTERNATIONAL & INLAND A vessel engaged in fishing while at anchor shall sound which fog signal?

  1. A rapid ringing of the bell for five seconds at one-minute intervals
  2. One prolonged and three short blasts at two-minute intervals
  3. One prolonged and two short blasts at two-minute intervals ✓
  4. A sounding of the bell and gong at one-minute intervals

Why: Rule 35(c): a vessel engaged in fishing sounds one prolonged and two short blasts at intervals not exceeding two minutes whether underway or at anchor; she does not switch to ordinary anchor signals while fishing.

Show all 20 sample questions with answers & explanations

Which statement is TRUE of a gasoline spill?

  1. It is not covered by the pollution laws.
  2. It will sink more rapidly than crude oil.
  3. It does little harm to marine life.
  4. It is visible for a shorter time than a fuel oil spill. ✓

When bunkering is complete, which is the correct procedure concerning the bunker hoses?

  1. The hose must be drained, blanked off, and stored securely ✓
  2. The hose must be stowed vertically and allowed to drain
  3. The hose should be washed out with hot soapy water
  4. The hose must be cleaned internally with a degreaser

When is a lookout permitted to leave his station?

  1. Only when properly relieved ✓
  2. At the end of the watch
  3. 15 minutes before the end of the watch
  4. At any time

Why: The lookout's duty is continuous, so the station may be left only when properly relieved. Even at the end of the watch, the relief must actually take over first.

What is the minimum standard for making an eye splice in a wire to be used as cargo gear?

  1. Make three tucks with full strands, remove half the wires from each strand, and make two more tucks. ✓
  2. Make four tucks with each full strand.
  3. Make six tucks with each strand, removing a few wires from each strand as each additional tuck is made.
  4. Make four tucks in each strand, cut away every other strand, and make two more tucks with each remaining strand.

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

Fueling results in the collection of waste oil in drip pans and containers. Which is an approved method of disposing of the waste oil?

  1. Mixing it with dispersants before draining it overboard
  2. Adding sinking agents and discharging it into the water
  3. Discharge to a proper reception facility ✓
  4. Draining it overboard when the vessel gets underway

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

Who has the authority to grant an alternate procedure for oil transfer operations?

  1. The Captain of the Port ✓
  2. The Officer-in-Charge, Marine Inspection
  3. The Area Commander
  4. The nearest Coast Guard office

Why: Under 33 CFR 156.107 the Captain of the Port may consider and approve alternatives to the required oil transfer procedures when they provide an equivalent level of safety and pollution protection.

Which is the correct procedure for anchoring a small to medium size vessel in deep water?

  1. Back the anchor slowly out of the hawsepipe a few feet, and then let it fall in the normal fashion.
  2. Let the anchor fall off the brake right from the hawsepipe, but keep a slight strain on the brake.
  3. Let the anchor fall free from the hawsepipe, but apply the brake at intervals to check the rate of fall.
  4. Under power, back the anchor out until it is near, but clear, of the bottom before letting it fall. ✓

Where are buoys and day beacons exhibiting a yellow triangle or square painted on them used?

  1. Locations where the ICW and other waterways coincide ✓
  2. Only at particularly hazardous turns of the channel
  3. On isolated stretches of the ICW to mark undredged areas
  4. In minor harbors where the controlling depth is 10 feet (3 meters) or less

What is NOT a characteristic of cardinal marks?

  1. White lights
  2. Yellow and black bands
  3. Square or triangular topmarks ✓
  4. Directional orientation to a hazard

Which part of the patent anchor performs the same function as the stock of an old-fashioned anchor; that is, forces the flukes to dig in?

  1. Shank
  2. Tripping Palm ✓
  3. Arm
  4. Bill or pea

Why: On a stockless (patent) anchor, the tripping palms are flat projections that bear against the seabed and force the flukes to rotate downward and dig in, doing the job the stock did on an old-fashioned anchor.

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

  1. Human error ✓
  2. Equipment failure
  3. Major casualties
  4. Unforeseeable circumstances

Why: Most minor oil spills come from human error, mistakes like unattended transfers, misaligned valves, or overfilled tanks, rather than equipment failure or major casualties. That is why transfer procedures and checklists exist.

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.

Why: 'Shift the rudder' orders the helmsman to swing the rudder to the same angle on the opposite side, for example from right 15° to left 15°. It is used to check a swing quickly.

Which is a feature of a special daymark?

  1. A red-and-white octagon
  2. A green square
  3. A yellow diamond ✓
  4. A daymark with a yellow stripe on it

Why: Special marks have no lateral significance and are yellow. The daymark form is a yellow diamond. Squares and triangles in green or red are lateral shapes; a red-and-white octagon is safe water.

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

Why: Geographic range assumes visibility permits and is limited purely by the curvature of the Earth, the horizon distance set by the heights of the light and observer. Luminous range deals with intensity and existing visibility.

A cardinal mark showing an uninterrupted quick-flashing white light indicates the deepest water is located in which quadrant?

  1. The west quadrant of the mark
  2. The north quadrant of the mark ✓
  3. The south quadrant of the mark
  4. The east quadrant of the mark

Why: An uninterrupted (continuous) quick-flashing white light identifies a north cardinal mark, think of a clock face with no number breaks at the top. Safe, deepest water lies north of the mark; pass on its north side.