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.
Exam-day conditions: no feedback until you submit, each module scored separately like the real test, with a full question-by-question review at the end.
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.
The free sample gives you 20 to 30 questions per module. The full bank contains every available official question, with written explanations on the popular small-vessel credentials, one-off $29, lifetime access on up to 3 devices, all credentials included.
Yes. OUPV (Operator of Uninspected Passenger Vessels) is commonly called the six-pack or charter captain's license, because it allows carrying up to six paying passengers.
You must pass each module separately. Rules of the Road requires 90%; most other modules require 70%. Chart-plotting modules are worked on paper.
The exam covers 3 modules: Rules of the Road, Deck General/Safety, Navigation General.
This page includes free sample questions drawn from the official USCG sample examinations, with a full bank of around 290 questions across all modules available with lifetime access.
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.
No. The free practice tests work in your browser with no signup. Your score history is saved on your own device.
A selection of free questions from the official USCG sample examinations. Use the interactive modules above for timed, scored drills.
INLAND ONLY Which term is NOT defined in the Inland Navigation Rules?
Why: Inland Rule 3 defines seaplane, restricted visibility, and underway, but deliberately omits 'vessel constrained by her draft.' That category exists only in International Rule 3(h) and has no status in inland waters.
INLAND ONLY Which of the following may be displayed by a law enforcement boat?
Why: The Inland Rules specifically authorize law enforcement vessels to display a flashing blue light when engaged in direct law enforcement operations. None of the other signals listed is authorized for that purpose.
INLAND ONLY Which of the following is indicated by a vessel displaying a flashing blue light?
Why: Under the Inland Rules a flashing blue light is reserved for law enforcement vessels engaged in direct law enforcement or public safety activity, so sighting one identifies a police or Coast Guard boat.
BOTH INTERNATIONAL & INLAND By definition which vessel is unable to keep out of the way of another vessel?
Why: Rule 3(g) defines a vessel restricted in her ability to maneuver as one whose work makes her 'unable to keep out of the way of another vessel.' The definitions of towing, fishing, and sailing vessels contain no such wording.
BOTH INTERNATIONAL & INLAND A vessel that is defined as "restricted in her ability to maneuver" is unable to keep out of the way of another vessel due to __________.
Why: Under Rule 3(g) the restriction must arise from the nature of her work, such as dredging, cable laying, or buoy servicing. Draft creates 'constrained by draft' (International only), and exceptional circumstances make a vessel 'not under command.'
INTERNATIONAL ONLY You intend to overtake a vessel in a narrow channel on its port side. The vessel to be overtaken has to take action to permit safe passing. How should you signal your intentions?
Why: International Rule 34(c): when the vessel ahead must take action to permit passing in a narrow channel, the overtaker sounds two prolonged followed by two short blasts, meaning 'I intend to overtake you on your port side' (Rule 9(e)).
INTERNATIONAL ONLY You are operating a vessel in a narrow channel. Your vessel must stay within the channel to be navigated safely. Another vessel is crossing your course from starboard to port, and you are in doubt as to his intentions. According to Rule 9, which statement is TRUE?
Why: When vessels in sight are approaching and you doubt the other's intentions or actions, Rule 34(d) provides the signal of at least five short and rapid blasts. Backing down or bound-to-hold signals are not prescribed.
BOTH INTERNATIONAL & INLAND In which situation do the Rules require both vessels to change course?
Why: Rule 14 requires each power-driven vessel meeting head-on to alter course to starboard, so both act. In crossing situations only the give-way vessel must initially act, and with wind on the same side only the windward sailing vessel keeps clear.
BOTH INTERNATIONAL & INLAND When two power-driven vessels are meeting head-on and there is a risk of collision, which action is required to be taken?
Why: Rule 14: in a head-on meeting with risk of collision, each vessel shall alter course to starboard so they pass port-to-port. Stopping, backing, or the doubt signal are not the prescribed actions.
BOTH INTERNATIONAL & INLAND Which is TRUE of a power-driven stand-on vessel?
Why: Rule 17 requires the stand-on vessel to hold course and speed, but permits her to act as soon as it is apparent the give-way vessel is not taking appropriate action, and requires action when collision becomes unavoidable otherwise.
BOTH INTERNATIONAL & INLAND You hear the fog signal of another vessel forward of your beam. Risk of collision may exist. You are required to take which action?
Why: Rule 19(e): on hearing a fog signal apparently forward of the beam, reduce speed to the minimum for steerage and, if necessary, take all way off. Merely stopping engines or starting a plot is not the required action.
BOTH INTERNATIONAL & INLAND You are underway in heavy fog. You hear the fog signal of a vessel which is somewhere ahead of your vessel. Which action(s) are you required to take?
Why: Rule 19(e) requires reducing speed to the minimum at which the vessel can be kept on course, taking all way off if necessary, and navigating with extreme caution until the danger of collision is over.
BOTH INTERNATIONAL & INLAND You are underway in restricted visibility. You hear the fog signal of another vessel about 20° on your starboard bow. Risk of collision may exist. Which action should you take?
Why: Vessels in restricted visibility are not 'in sight' of one another, so the crossing rules do not apply. Rule 19(e): hearing a fog signal apparently forward of your beam, reduce speed to the minimum at which you can keep on course until danger of collision is over.
INLAND ONLY The masthead light may be located at other than the fore and aft centerline on which power- driven vessel?
Why: The Inland Rules' annex provisions allow a power-driven vessel under 12 meters to carry her masthead or all-round light off the fore-and-aft centerline when centerline mounting is not practicable. Larger vessels must keep it on centerline.
INLAND ONLY What signal is a power-driven vessel, when leaving a dock or berth, required to sound?
Why: Inland Rule 34(g) requires a power-driven vessel leaving a dock or berth to sound one prolonged blast, warning vessels that may be approaching unseen. This signal exists only in the Inland Rules.
BOTH INTERNATIONAL & INLAND Which vessel(s) is/are required to sound a fog signal of one prolonged followed by two short blasts?
Why: Rule 35(c) assigns one prolonged plus two short blasts to vessels not under command, restricted in ability to maneuver (underway or at anchor when working), constrained by draft, sailing, fishing, or towing, so every choice qualifies.
Which term defines when a vessel is swinging from side to side off course due to quartering seas?
Why: Yawing is the swinging of the bow from side to side off the intended heading, typical in quartering seas. Broaching is being thrown broadside in a trough; rolling is side-to-side rotation; pitchpoling is end-over-end capsizing.
When is a lookout permitted to leave his station?
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.
How does good housekeeping prevent fires on a vessel?
Why: Fire needs fuel, heat, and oxygen. Good housekeeping removes accumulated trash, oily rags, and spilled flammables, the fuel side of the fire triangle, so ignition sources have nothing to start on.
Which action should you take after sending a false distress alert on VHF?
Why: A false distress alert transmitted by VHF voice is canceled by an all-stations voice broadcast on Channel 16, the distress and calling channel where the alert was heard, identifying your vessel and canceling the alert.
A List of Lights entry (L Fl) is a single flashing light which shows a long flash of not less than which duration?
Why: A long flash (L Fl) is defined as a flash of not less than 2 seconds duration, distinguishing it from an ordinary flash, which is shorter.
Which level of accuracy can be obtained utilizing the U.S. Coast Guard's Maritime Differential GPS in an established coverage area?
Why: The Coast Guard's maritime Differential GPS broadcast corrections that provided 10-meter accuracy (typically better) throughout its established coverage areas.
What is the color scheme of navigational marks used for informational or regulatory purposes?
Why: Information and regulatory marks are white with orange geometric shapes (open diamonds for danger, circles for controlled areas, squares for information) and black lettering.
Your vessel is proceeding up a channel, and you see a pair of range lights that are in line ahead. The chart indicates that the direction of this pair of lights is 014°T, and the variation is 11°E. If the heading of your vessel at the time of the sighting is 009° per standard magnetic compass, what is the correct deviation?
Why: Range true 014 minus variation 11E gives 003 magnetic. Heading on the range reads 009 by compass. Deviation = magnetic minus compass = 003 - 009 = 6W.
Which agency publishes the Light Lists?
Why: The U.S. Coast Guard publishes the Light List, describing lights, buoys, and other aids to navigation in U.S. waters. Charts and tide data come from the National Ocean Service.
You have been informed that dredging operations may be underway in your vicinity. Which buoy indicates the dredging area?
Why: Dredging and survey operations are marked with special-purpose buoys, which are solid yellow under the IALA system.
While on a course of 349°T, a light bears 13° on your starboard bow at a distance of 10.8 miles. What course should you steer to pass 2.5 miles abeam of the light, leaving it to starboard?
Why: On the present course the light is 13 degrees off the bow at 10.8 miles, so CPA = 10.8 x sin 13 = about 2.4-2.5 miles, with the light to starboard. Maintaining 349T already gives the desired passing distance.
Which factor is most likely to impair the strength and durability of synthetic line?
Why: Ultraviolet radiation in sunlight breaks down synthetic fibers and weakens the line. Unlike natural fiber rope, synthetics are essentially immune to mildew and rot, so sunlight is their chief environmental enemy.
What is the period of validity of a Merchant Mariner Credential?
Why: A Merchant Mariner Credential is issued for a five-year term and must be renewed before it expires.
Which U.S. agency assigns an official number to a vessel?
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.
Which is the requirement for the name and hailing port of a documented commercial vessel?
Why: Documentation regulations require a commercial vessel's name on both bows and the name and hailing port on the stern. Nothing is ever marked on the keel.
If heavy smoke is coming from the paint locker, what should be the FIRST firefighting response?
Why: Fire needs oxygen, so securing ventilation starves and contains a paint locker fire. Opening the door feeds it air and invites a flare-up; CO2 release or entry comes after the space is isolated.
On a chart, the characteristic of the light on a lighthouse is shown as flashing white with a red sector. Which is TRUE of the red sector?
Why: Red sectors are arcs drawn to cover dangers such as shoals, rocks, or obstructions. Seeing the light turn from white to red means your bearing line lies within the charted danger area.
Barometer readings in weather reports are given in terms of pressure at which reference location?
Why: Barometric pressures in reports are reduced to sea level so readings from stations at different elevations are comparable; otherwise altitude differences would mask the real pressure pattern.
Your vessel is on a course of 221°T at 15 knots. At 0319 a light bears 198.5°T, and at 0353 the light bears 176°T. At what time and distance off will your vessel be when abeam of the light?
Why: Bow angles double from 22.5 to 45 degrees, so distance off at 0353 equals the run: 34 min at 15 kn = 8.5 mi. Beam distance = 8.5 x sin 45 = 6.0 mi; run to abeam = 6.0 mi = 24 min, giving 0417.
Under the IALA Buoyage Systems, which is TRUE of safe water marks?
Why: IALA safe water marks show white lights with isophase, occulting, single long-flash, or Morse 'A' rhythm. Composite group flashing (2+1) red or green belongs to preferred-channel marks, and Q(9) is a west cardinal characteristic.
What is published by the U.S. Coast Guard?
Why: The Coast Guard publishes the Light List. Coast Pilots, nautical charts, and tide tables are products of NOAA's National Ocean Service.
What will a veering wind do?
Why: A veering wind shifts direction clockwise (for example south to southwest to west) in the Northern Hemisphere; a backing wind shifts counterclockwise. The term describes the shift itself, not circulation around a pressure system.
In the IALA Buoyage System, what do buoys with alternating red and green horizontal bands indicate?
Why: Red and green horizontally banded buoys are preferred-channel (junction) marks: the color of the top band shows which side to pass for the preferred channel. Solid yellow marks special areas.
You are docking a vessel. When are the wind and current most favorable in this situation?
Why: With wind and current from ahead and parallel to the pier, you can stem them, keeping steerageway with little speed over the ground for maximum control. Cross-setting forces push you onto or off the berth unpredictably.
You are 15 feet off a pier and docking a vessel using only a bow breast line and stern breast line. Once the slack is out of both lines you begin to haul in on the bow breast line. What is the effect on the vessel?
Why: A breast line leads at right angles to the pier and moves only its own end of the vessel. Hauling on the bow breast pulls the bow alongside while the stern breast simply holds the stern at its existing distance.
In a following sea, a wave has overtaken your vessel and thrown the stern to starboard. To continue along your original course, which action should you take?
Why: When a following sea kicks the stern to starboard, the bow swings to port off course. Right rudder checks that swing and brings the bow back. Changing speed alone does not correct the yaw.
Which action should be taken prior to assuming the Deck Watch while the vessel is in port?
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.
Which is an advantage of an ABC dry chemical over a carbon dioxide extinguisher?
Why: ABC dry chemical extinguishes Class A, B, and C fires, while CO2 is effective mainly on Class B and C. That broader multipurpose capability is the advantage; both leave electrical gear concerns to CO2, which is actually cleaner.
Which extinguishing agent is most effective on a mattress fire?
Why: A mattress fire is a deep-seated Class A fire. Water soaks into the material, cooling below ignition temperature throughout. Gas agents like CO2 or Halon only smother the surface, so the fire can rekindle inside.
You sight a buoy fitted with a double-sphere topmark. If sighted at night, what color and light sequence would you expect to see?
Why: A double-sphere (two black balls) topmark identifies an isolated danger mark. Its light is white, showing groups of two flashes, matching the two spheres of the topmark.
Your vessel is proceeding up a channel steering on a pair of range lights that are in line ahead. The chart indicates that the direction of this pair of lights is 249°T, and the variation is 14°E. If the heading of your vessel at the time of the sighting is 226° per standard magnetic compass, what is the correct deviation?
Why: Ranges give an exact true bearing. 249°T minus 14°E variation = 235° magnetic. Compass read 226°, which is 9° less than magnetic, so deviation is 9°E (compass least, error east).
Which defines a light's luminous range?
Why: Luminous range is the greatest distance a light can be seen based on its intensity and the existing visibility, ignoring observer height and Earth's curvature. Range limited by curvature and heights is geographic range.
What is indicated when slanted letters are used to spell the name of a charted object?
Why: Chart convention: slanted (italic) lettering labels floating or submerged features such as buoys and underwater hazards; upright lettering labels features that are dry at high water. It is a quick visual cue about the object's nature.
Aneroid barometers are usually calibrated to indicate atmospheric pressure in which units?
Why: Aneroid barometers carry dual scales in inches of mercury and millibars (hectopascals), the two standard units for reporting atmospheric pressure at sea.
If a gasoline engine turns over freely but will not start, the cause is generally __________.
Why: An engine that cranks freely has fuel, compression, or spark as the usual suspects, and in gasoline engines the ignition system (plugs, points, coil, wiring) is the most common failure. Load and lube problems would not prevent firing.
An important step in fighting any electrical fire is to take which action?
Why: De-energizing removes the source feeding the fire and removes the electrocution hazard; once dead, it can be fought as an ordinary fire. Water on a live circuit endangers the firefighter.
What is required in addition to the heat, fuel, and oxygen of the fire triangle to have a fire?
Why: Modern fire theory uses the fire tetrahedron: heat, fuel, oxygen, plus an uninhibited chemical chain reaction. Dry chemical agents work largely by interrupting that chain reaction.
Which visual distress signal is acceptable for daylight use only?
Why: Orange smoke is visible only by day, so hand-held orange smoke signals are approved for daylight use only. Red flares, hand-held or aerial, are approved for both day and night.
When dry chemical extinguishers are used to put out class B fires, why is there a danger of reflash?
Why: Dry chemical knocks down Class B flames by interrupting the chain reaction but provides little or no cooling, so hot surfaces and fuel above its flash point can reignite (reflash) once the agent dissipates.
You are proceeding in a channel, your vessel is requiring a significant amount of right rudder and your bow is still falling off to port. What can you conclude from this information?
Why: Bank cushion shoving the bow off and bank suction pulling the stern toward the near bank produce exactly this: constant rudder toward the bank yet the bow still falls away, a sign you are at the channel's outer edge.
BOTH INTERNATIONAL & INLAND When action to avoid a close-quarters situation is taken, a course change alone may be the most effective action provided that __________.
Why: Rule 8 says an alteration of course alone may be the most effective action if it is substantial (large enough to be readily apparent), made in good time, and does not create another close-quarters situation. Small successive changes are to be avoided.
BOTH INTERNATIONAL & INLAND You are approaching another vessel at night. You can see both red and green sidelights and, above the level of the sidelights, three white lights in a vertical line. Which vessel is required to have these lights?
Why: Under Rule 24, a towing vessel whose tow extends more than 200 meters astern shows three masthead lights in a vertical line, plus sidelights, which explains seeing red, green, and three white lights.
INLAND ONLY When two power-driven vessels are meeting on the Great Lakes, Western Rivers, or waters specified by the Secretary, where there is a current, which vessel shall sound the first passing signal?
Why: Inland Rule 14(d): on these waters the downbound vessel with a following current has the right-of-way, proposes the manner of passage, and sounds the first signal, because the current makes her harder to stop and maneuver.
BOTH INTERNATIONAL & INLAND When is your vessel traveling at a "safe speed" as defined in the COLREGS?
Why: Rule 6 defines safe speed as one allowing proper and effective action to avoid collision and stopping within a distance appropriate to conditions. It is not measured against other vessels, wake, or simply stopping within visibility range.
INLAND ONLY A law enforcement vessel patrolling a marine regatta may exhibit a flashing blue light or which of the following alternates?
Why: Under the Inland Rules, a vessel engaged in public safety activities, such as patrolling a regatta, may display an alternately flashing red and yellow identity light as the alternative to the law-enforcement flashing blue light.
BOTH INTERNATIONAL & INLAND Which is TRUE for a vessel using a traffic separation scheme?
Why: Rule 10 directs vessels to avoid anchoring within a traffic separation scheme or near its terminations, where converging traffic concentrates. Crossing, when obliged, must be at as near a right angle as practicable, not a small angle.
BOTH INTERNATIONAL & INLAND You are approaching another vessel on crossing courses. She is about one mile distant and is on your starboard bow. You believe she will cross ahead of you but she sounds a whistle signal of five short blasts. Which action should you take?
Why: Five short blasts is the danger/doubt signal (Rule 34(d)), she doubts you will keep clear. Rule 8 requires action that is substantial and made in ample time: a large, readily apparent course change, slowing if necessary.
BOTH INTERNATIONAL & INLAND Your power-driven vessel is stopped and making no way, but is not in any way disabled. Another vessel is approaching you on your starboard beam. Which statement is TRUE?
Why: A vessel stopped but not anchored or disabled is still a power-driven vessel underway. Under Rule 15, with the other vessel on your starboard side in a crossing situation, you are the give-way vessel; being stopped grants no privilege.
BOTH INTERNATIONAL & INLAND Which vessel should not impede the navigation of a power-driven vessel?
Why: Rule 18(e) requires a seaplane on the water to keep well clear of all vessels and avoid impeding their navigation. The other vessels listed are ones a power-driven vessel must keep out of the way of.
INLAND ONLY For the purpose of the Inland Navigation Rules, the term "Inland Waters" includes which of the following?
Why: The Inland Rules define inland waters as U.S. navigable waters shoreward of the demarcation lines, plus the Western Rivers (Mississippi River System). The Great Lakes are included only on the U.S. side, and waters seaward of the lines are COLREGS waters.
BOTH INTERNATIONAL & INLAND You are on watch in fog. Which vessel is "in sight"?
Why: Rule 3 defines vessels as "in sight" only when one can be observed visually from the other. Radar contacts and heard fog signals do not count, which is why the conduct rules differ in restricted visibility.
BOTH INTERNATIONAL & INLAND A vessel hearing a fog signal forward of her beam has not determined if risk of collision exists. What shall she reduce speed to?
Why: Rule 19(e): hearing a fog signal apparently forward of the beam, a vessel shall reduce speed to the minimum at which she can be kept on course, bare steerageway, and if necessary take all way off.
BOTH INTERNATIONAL & INLAND Which vessel shall exhibit a rigid replica of the International Code flag "A"?
Why: Rule 27(e): a vessel engaged in diving operations, when too small to show the shapes for restricted maneuverability, exhibits a rigid replica of code flag "A" (Alfa) to warn others to keep clear of divers below.
BOTH INTERNATIONAL & INLAND In a crossing situation of two power-driven vessels, the vessel which has the other on her own starboard side shall take which action?
Why: Rule 15: in a crossing situation the vessel with the other on her starboard side is the give-way vessel and shall, if circumstances admit, avoid crossing ahead. Turning to port for a vessel forward of the beam should be avoided.