Top 10 Hardest Coast Guard NAVRULES Questions

It has now been about a year and a half since the CaptainQuiz NAVRULES Android app was first released. With hundreds of users having played thousands of games and answered over 200,000 Rules of the Road (ROTR) questions since August of 2012, we are getting some really interesting data. (As our users know, our apps anonymously report these statistics for quality control and research like this.)

It has been fascinating to look at overall performance across the entire U.S. Coast Guard question bank. But maybe the most useful result is that we can see exactly what kinds of questions give test takers the most trouble. We plan to run a series of posts on these results for the deck and engineering tests as well, but for now we present to you the Top 10 Hardest NAVRULES questions.

What we found was fascinating: although the average rate of correct answers is between 75% and 80%, there are a few extremely difficult, tricky questions that users get wrong all the time.

Most of the questions are answered correctly most of the time, but there are some nasty questions lurking in the test bank.

As you can see from the graph, most of the questions are answered correctly most of the time but there are a handful of particularly nasty questions lurking in the test bank — test takers consistently get these wrong more than any other questions, so it might be worth keeping an eye out for these ones when taking your USCG license exam! Without further ado, here they are:

    • #10

      Which signal is required to be sounded by a power-driven vessel ONLY?
      INTERNATIONAL ONLY
      (a) A signal meaning, 'I am altering my course to starboard.'
      (b) A signal meaning, 'I intend to overtake you on your starboard side.'
      (c) A signal meaning that the vessel sounding it is in doubt as to the other vessel's actions.
      (d) A signal sounded when approaching a bend.
       

      Answered correctly: 38% of the time

      Correct answer: Choice (a)

      Explanation:

      This type of question trips up even experienced mariners. The key hint here is that this question is required for power-driven vessels (PDV) only, and that the zone is INTERNATIONAL ONLY. Rule 34(a) makes clear that
      (a) When vessels are in sight of one another, a power-driven vessel underway, when maneuvering as authorized or required by these Rules, shall indicate that maneuver by the following signals on her whistle: − one short blast to mean 'I am altering my course to starboard' ...
      What makes this question really tricky is that this is only required "when vessels are in sight of one another," but we have some excellent clues as to why this must be correct answer. Choice (b) can't be correct since 'I intend' and all signals of intention are INLAND ONLY. (Memory aid: "INLAND/INTEND".) Choice (c) can't be correct if you remember that the signal for doubt is not usually required, and if it were there is no reason it would be required for PDVs only. Choice (d) can't be correct since the signal for a vessel nearing a bend (one prolonged blast) is not restricted to PDVs. That leaves choice (a).
    • #9

      You see the display of lights shown. This could indicate a ____.
      diagram64
      BOTH INLAND AND INTERNATIONAL
      (a) dredge working at anchor
      (b) dredge restricted in its ability to maneuver
      (c) 55-meter tug towing astern, length of tow exceeds 200 meters
      (d) 65-meter tug towing astern, length of tow 150 meters
       

      Answered correctly: 37% of the time

      Correct answer: Choice (d)

      Explanation:

      Let's break this picture down. We know we're looking at a vessel from the front. How do we know that? We can see both sidelights — that's only true when you're looking at a vessel head on. That means the white lights we're seeing above are either masthead lights or all-around lights. Rule 24(a) tells us the following:
      (a) A power-driven vessel when towing shall exhibit: (i) instead of the light prescribed in Rule 23(a)(i) or (a)(ii), two masthead lights in a vertical line. When the length of the tow, measuring from the stern of the towing vessel to the after end of the tow exceeds 200 meters, three such lights in a vertical line; (ii) sidelights; (iii) a sternlight; (iv) a towing light in a vertical line above the sternlight; and (v) when the length of the tow exceeds 200 meters, a diamond shape where it can best be seen.
      What we're seeing here is a towing vessel (memory aid: "white over white, towing at night"). Before we discuss choices (c) and (d), let's just get (a) and (b) out of the way. There is no way this light configuration has anything to do with dredging; don't be confused by the unusually large number of white lights. For one thing, the only thing special about dredge lighting is explained in Rule 27 and Annex I(4), where you get the red-over-red and green-over-green indicating dangerous and safe sides to pass. Otherwise, they would be showing normal restricted in ability to maneuver (RAM) or anchor lights just like any other PDV.

      Selection_033

      Now let's dig in to choices (c) and (d). The mystery here is why we're seeing a third white light. Rule 24(a) above states "[w]hen the length of the tow, measuring from the stern of the towing vessel to the after end of the tow exceeds 200 meters, three such lights in a vertical line" which can explain it, but let's not forget that Rule 24(d) states:

      (d) A power-driven vessel to which paragraph (a) or (c) of this Rule apply shall also comply with Rule 23(a)(ii).
      To understand why this is important, let's take a look at Rule 23:
      (a) A power-driven vessel underway shall exhibit: (i) a masthead light forward; (ii) a second masthead light abaft of and higher than the forward one; except that a vessel of less than 50 meters in length shall not be obliged to exhibit such light but may do so;
      Mystery solved. Since both vessels are greater than 50 meters, the third light can be explained that way. However, choice (c) adds an extra wrinkle by making the length of tow greater than 200 meters. That's just a distraction because we're not seeing anything that isn't already explained by a vessel towing which is greater than 50 meters — the correct choice is (d).
    • #8

      If a towing vessel and her tow are severely restricted in their ability to deviate from their course, the towing vessel shall show lights in addition to her towing identification lights. These additional lights shall be shown if the tow is _.
      INTERNATIONAL ONLY
      (a) pushed ahead
      (b) towed alongside
      (c) towed astern
      (d) All of the above
       

      Answered correctly: 37% of the time

      Correct answer: Choice (c)

      Explanation:

      Most questions about towing lights will be INTERNATIONAL ONLY or INLAND ONLY because the lighting requirements are very different. This question is kind of a stumper, and probably because it is outdated. A 2008 blog post from Gary's Nautical Information has the following to say:
      There is a difference between the International Rules and the Inland Rules in this respect. The International Rule 27(c) requires the restricted in ability to maneuver lights (RAM) only when towing astern. The Inland Rule 27(c) requires the RAM lights regardless of the position of the tow. Also note that the International Rule refers to vessels towed in Rule 24 (a) only, while the Inland Rule refers to all the vessels towed in Rule 24.
      However, that doesn't necessarily look to be the case any more, and this question may actually be outdated. In any case, the correct answer (at least at one time) was choice (c). If anyone has more insight about this question, please let us know!
      Warning! Sometimes there are outdated questions in the official USCG question bank. In our app, we keep them as-is so that mariners know what to expect on the actual test. As always, the Coast Guard's most up-to-date official information (and contact information) is available here.
       
    • #7

      Which vessel must show an after masthead light, if over 50 meters in length?
      BOTH INLAND AND INTERNATIONAL
      (a) A vessel engaged in fishing
      (b) A vessel at anchor
      (c) A vessel not under command
      (d) A vessel trawling
       

      Answered correctly: 37% of the time

      Correct answer: Choice (d)

      Explanation:

      This is a good candidate for figuring out the answer by elimination. Vessels at anchor show anchor lights, which does not involve an after masthead light. A vessel not under command (NUC) only shows two all-around red lights in a vertical line (memory aid: "red over red: captain is dead"), except when making way in which case they would also show sidelights and a stern light. That brings us to Rule 26:
      (a) A vessel engaged in fishing, whether underway or at anchor, shall exhibit only the lights and shapes prescribed in this Rule. (b) A vessel when engaged in trawling, by which is meant the dragging through the water of a dredge net or other apparatus used as a fishing appliance, shall exhibit: (i) two all-round lights in a vertical line, the upper being green and the lower white, or a shape consisting of two cones with their apexes together in a vertical line one above the other; (ii) a masthead light abaft of and higher than the all-round green light; a vessel of less than 50 meters in length shall not be obliged to exhibit such a light but may do so; (iii) when making way through the water, in addition to the lights prescribed in this paragraph, sidelights and a sternlight.
      Case closed.
    • #6

      In restricted visibility, a vessel which detects by radar alone the presence of another vessel shall determine if a close quarters situation is developing or risk of collision exists. If so, she shall _.
      BOTH INLAND AND INTERNATIONAL
      (a) sound the danger signal
      (b) when taking action, make only course changes
      (c) avoid altering course toward a vessel abaft the beam
      (d) All of the above
       

      Answered correctly: 36% of the time

      Correct answer: Choice (c)

      Explanation:

      Let's go straight to Rule 19(d):
      (d) A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provided that when such action consists of an alteration of course, so far as possible the following shall be avoided: (i) an alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken; (ii) an alteration of course towards a vessel abeam or abaft the beam.
      Here's a quick visual aid that is so ugly it might help you remember:

      Pretty simple, right?
      Pretty simple, right? If your radar screen shows a contact either ahead and to port or abaft the beam, then Rule 19 has specific prohibitions about how you may maneuver. In this case, choice (c) is the correct choice.
    • #5

      Signals required for vessels aground include _.
      BOTH INLAND AND INTERNATIONAL
      (a) by night, the anchor lights for a vessel of her length, and three red lights in a vertical line
      (b) a short, a prolonged, and a short blast
      (c) by day, three black balls in a vertical line
      (d) All of the above
       

      Answered correctly: 35% of the time

      Correct answer: Choice (c)

      Explanation:

      There is a great mnemonic for this one: "it takes a lot of balls to run aground" — the correct answer is choice (c).
    • #4

      A vessel displaying the lights shown could be a vessel _.
      diagram56
      BOTH INLAND AND INTERNATIONAL
      (a) fishing at anchor
      (b) dredging while underway
      (c) transferring dangerous cargo at a berth
      (d) restricted in her ability to maneuver, underway but not making way
       

      Answered correctly: 35% of the time

      Correct answer: Choice (b)

      Explanation:

      Everybody has problems with dredges. They're just weird, and hard to remember. But here's the deal, Rule 27(d):
      (d) A vessel engaged in dredging or underwater operations, when restricted in her ability to maneuver, shall exhibit the lights and shapes prescribed in subparagraphs (b)(i), (ii) and (iii) of this Rule and shall in addition, when an obstruction exists, exhibit: (i) two all-round red lights or two balls in a vertical line to indicate the side on which the obstruction exists; (ii) two all-round green lights or two diamonds in a vertical line to indicate the side on which another vessel may pass; (iii) when at anchor, the lights or shapes prescribed in this paragraph instead of the lights or shape prescribed in Rule 30.
      So basically, RAM with some other stuff if there's an obstruction. What is RAM?
      (b) A vessel restricted in her ability to maneuver, except a vessel engaged in mine clearance operations, shall exhibit: (i) Three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white; (ii) Three shapes in a vertical line where they can best be seen. The highest and lowest of these shapes shall be balls and the middle one a diamond; (iii) When making way through the water, masthead lights, sidelights and a sternlight, in addition to the lights prescribed in subparagraph (b)(i); and (iv) When at anchor, in addition to the lights or shapes prescribed in subparagraphs (b)(i) and (ii), the light, lights or shapes prescribed in Rule 30.
      Here's an old-school memory aid for RAM dayshapes: "it's hard to maneuver with a diamond between your balls." Cute, right? Here's what you're seeing.

      Selection_034

      Not simple, but not so bad.

    • #3

      Which statement is TRUE concerning the fog signal of a sailing vessel 25 meters in length, anchored in a 'special anchorage area' approved by the Secretary?
      INLAND ONLY
      (a) The vessel is not required to sound a fog signal.
      (b) The vessel shall ring a bell for 5 seconds every minute.
      (c) The vessel shall sound one blast of the whistle every 2 minutes.
      (d) The vessel shall sound three blasts on the whistle every 2 minutes.
       

      Answered correctly: 35% of the time

      Correct answer: Choice (b)

      Explanation:

      There is some misdirection here. The whole "special anchorage area" part is just designed to throw us off the trail. In fact, as many sailors know, special anchorage areas allow small vessels to anchor without lights and shapes. Rule 30(g) (INLAND ONLY):
      (g) A vessel of less than 20 meters in length, when at anchor in a special anchorage area designated by the Secretary, shall not be required to exhibit the anchor lights and shapes required by this Rule.
      Again though, this doesn't even apply because our question specifies a sailing vessel 25 meters in length. Rule 35(f) is the only thing going on here:
      (f) A vessel at anchor shall at intervals of not more than 1 minute ring the bell rapidly for about 5 seconds. ...
      Choice (b) is the correct choice.
    • #2

      Signals shall be sounded by a power-driven vessel intending to overtake ____.
      INLAND ONLY
      (a) any vessel when within half a mile of that vessel
      (b) another power-driven vessel when both power-driven vessels are in sight of one another
      (c) any vessel when both are in sight of one another
      (d) another power-driven vessel only when within half a mile of that power-driven vessel
       

      Answered correctly: 31% of the time

      Correct answer: Choice (b)

      Explanation:

      People confuse inland signals of intent for a couple reasons. First of all the "half a mile" thing sounds too arbitrary to be real — but it is. However, that only applies to "meeting or crossing," but not overtaking:
      (a) When power-driven vessels are in sight of one another and meeting or crossing at a distance within half a mile of each other, each vessel underway, when maneuvering as authorized or required by these Rules ...
      There's also some confusion about when vessels are required to propose maneuvers and when they're supposed to wait, and the whole downbound/upbound right of way. In short, there is a lot to keep in mind.

      In this case, however Rule 34(c)(i) applies pretty clearly:

      (c) When in sight of one another: (i) a power-driven vessel intending to overtake another power-driven vessel shall indicate her intention by the following signals on her whistle: one short blast to mean "I intend to overtake you on your starboard side"; two short blasts to mean "I intend to overtake you on your port side"; ...
      That's about all there is to it.

       

      Which brings us to the #1 most commonly mistaken NAVRULES question...

    • #1

      The tug shown is greater than 50 meters and severely restricted in her ability to deviate from her course. Which lights would be displayed from the towing vessel?
      diagram24
      BOTH INLAND AND INTERNATIONAL
      (a) Two white masthead lights, red-white-red all round lights, sidelights, stern light and a towing light
      (b) Three white masthead lights, red-white-red all round lights, sidelights and two towing lights
      (c) Three white masthead lights, two all round red lights, sidelights, stern light and a towing light
      (d) None of the above
       

      Answered correctly: 29% of the time

      Correct answer: Choice (d)

      Explanation:

      The devilish thing about this questions is that (a) through (c) are all almost correct, but not quite! Choice (a) is wrong because vessels greater than 50 meters would have three white masthead lights ("white over white" plus an extra after mastehead light for being greater than 50 meters). Choice (b) is wrong because the vessel would not have two towing lights. Choice (c) is wrong because "two all around red lights" is for not under command (NUC), not RAM as in the question. We are left with choice (d), none of the above! (The actual light configuration would be similar to that described in choice (c) except red-white-red all around lights for RAM instead of the red-over-red for NUC.)
We hope this has been entertaining (and maybe even instructive). Stay tuned for more posts like this one. And if you want to get a leg up on your NAVRULES knowledge, whether you're studying for a license exam or just want to step your nautical game up, check out our Android app in the Google Play store.


Photo courtesy of gcaptain.com.