GLI01 - Master-Unlimited Tonnage

The Correct Answer is C. ### Explanation for C (white stern light) **Option C (white stern light) is correct** because vessel "A" is the overtaking vessel. According to the International Regulations for Preventing Collisions at Sea (COLREGs), a vessel is considered to be overtaking if it approaches another vessel from a direction more than $22.5^\circ$ abaft its beam (i.e., from behind). The only light that the overtaking vessel "A" will be able to see on the overtaken vessel "B" when approaching strictly from the stern is the **white stern light**. The stern light is a white light placed as nearly as practicable at the stern, showing an unbroken light over an arc of the horizon of $135^\circ$ (R. 21(d)), precisely covering the arc from which a vessel is considered to be overtaking. ### Explanation for Incorrect Options * **A) green sidelight:** The green sidelight (starboard side) shows over an arc of $112.5^\circ$ forward, from the bow to $22.5^\circ$ abaft the beam on the starboard side (R. 21(b)). Since vessel "A" is overtaking vessel "B" (approaching from astern), it is outside the arc of visibility for the green sidelight. * **B) yellow towing light:** A yellow towing light is carried instead of the normal stern light only if the vessel is engaged in towing (R. 21(d)). While this light also covers the $135^\circ$ arc astern, it is a specialized light indicating a towing operation. In the absence of specific information that vessel "B" is towing, the general light observed astern is the standard **white stern light**. The white stern light is the most accurate general answer for any vessel being overtaken. * **D) None of the above:** This is incorrect because the white stern light (Option C) is the correct light observed when overtaking.

The Correct Answer is C **Explanation for C (Correct Option):** Option **C** correctly illustrates the length of a vessel as defined by both International and Inland Rules (COLREGs, Annex I, Section 5, and corresponding Inland regulations). The "length of a vessel" used in relation to the application of the Rules (e.g., sound signaling appliance requirements, size of lights/day shapes) is defined as **Length Overall (LOA)**. Length Overall is the maximum dimension of the vessel measured between the foremost point and the aftermost point (including all fixed parts like bowsprits, pulpits, or fixed stern structures, but usually excluding retractable items or temporary additions). Illustration C spans the entire distance from the very front (bow) to the very back (stern). **Explanation of Incorrect Options:** * **A) A is incorrect:** Illustration A represents the vessel's **draft**. Draft is the vertical distance between the waterline and the bottom of the hull (keel). It defines the minimum depth of water the vessel needs to float. * **B) B is incorrect:** Illustration B represents the **beam** or breadth of the vessel. Beam is the maximum width of the vessel, measured side-to-side. * **D) D is incorrect:** Illustration D represents the **length between perpendiculars (LBP)**. LBP is a naval architecture measurement defined as the distance between the forward perpendicular (usually the intersection of the stem and the waterline) and the after perpendicular (often the axis of the rudder stock). LBP is used for stability calculations and tonnage measurement but is **not** the length used by the Rules (COLREGs/Inland) for defining vessel size categories.

The Correct Answer is B **Explanation for Option B (Correct Answer):** This scenario is governed by the International Regulations for Preventing Collisions at Sea (COLREGS) Rule 13 (Overtaking) and Rule 17 (Action by Stand-on Vessel). 1. **Rule 13 (Overtaking):** Vessel "A" is the overtaking vessel (the vessel wishing to pass) and is therefore the **Give-way vessel**. Vessel "B" is the vessel being overtaken and is therefore the **Stand-on vessel**. Rule 13(d) states that no subsequent alteration of the bearing between the two vessels shall make the overtaking vessel a crossing vessel or relieve her of the duty of keeping clear until she is finally past and clear. 2. **Rule 17 (Action by Stand-on Vessel):** This rule dictates the action of the vessel which is required to keep her course and speed. The stand-on vessel (Vessel B) must initially **hold her course and speed** to allow the give-way vessel (Vessel A) to take effective action to pass safely and keep clear. Therefore, Vessel "B" must hold her course and speed. **Explanation of Incorrect Options:** * **A) should slow down until vessel "A" has passed:** This is incorrect. Changing speed (slowing down) violates Rule 17, which requires the stand-on vessel to maintain course and speed. Changing speed makes it harder for the give-way vessel (A) to accurately judge the passing maneuver. * **C) may steer various courses and vessel "A" must keep clear:** This is incorrect. While vessel "A" must keep clear, vessel "B" (the stand-on vessel) is specifically required by Rule 17 to maintain a steady course and speed. Steerage various courses would confuse the situation and increase collision risk. * **D) should change course to the right:** This is incorrect. Vessel "B" is the stand-on vessel and must maintain course and speed. Changing course (especially unnecessarily to the right) would interfere with Vessel "A's" required maneuver to keep clear.

The Correct Answer is A ### Explanation for Option A (fishing vessel) A fishing vessel (underway and engaged in fishing) is required by both the International Regulations for Preventing Collisions at Sea (COLREGs) and the Inland Rules to display unique identifying lights: two all-round lights in a vertical line, typically **Green over White** (for fishing other than trawling) or **Red over White** (for trawling). These specific lights signal that the vessel is restricted in its ability to maneuver due to its gear. Since this specific light configuration is mandatory and serves as the primary identifier for the activity, it must be displayed consistently regardless of whether the vessel is operating internationally or on U.S. inland waters. ### Explanation of Why Other Options Are Incorrect **B) motorboat:** A motorboat (a power-driven vessel) displays only standard positional lights: a masthead light, sidelights, and a stern light. It does not display the unique configuration (like Green over White or Red over White) used by restricted vessels engaged in fishing. **C) sailboat:** A sailboat (sailing vessel) displays sidelights and a stern light. While it may optionally display all-round red over green lights at the masthead, it does not display the lights required for a vessel engaged in fishing. **D) pilot boat:** A pilot boat engaged in pilotage duty is required to display all-round **White over Red** lights ("White over Red, Pilot ahead"). This configuration is distinct from the Green over White or Red over White lights displayed by a fishing vessel.

The Correct Answer is D **Explanation for Option D (All of the above):** Inland Rule 9(a)(ii) and (b) govern vessels meeting in a narrow channel. When two power-driven vessels are meeting in a narrow channel on the Great Lakes, the specific conditions outlined in the scenario trigger several key responsibilities for the downbound vessel (Vessel A), especially because it is traveling with a following current. 1. **Propose the manner of passage (A):** Great Lakes Annex 5, Rule 3(a) specifically states that when power-driven vessels are meeting in a narrow channel on the Great Lakes, the downbound vessel (Vessel A) must propose the manner of passage, usually by initiating a signal of one blast (port-to-port) or two blasts (starboard-to-starboard). 2. **Initiate the maneuvering signals (B):** As the vessel proposing the manner of passage (A), Vessel A is responsible for initiating the required maneuvering signals (whistle blasts) to communicate its intent to the upbound vessel (Vessel B). This is required by Great Lakes Annex 5, Rule 3(a). 3. **Have the right of way (C):** Inland Rule 9(a)(ii) gives preference (often interpreted as "right of way" in this context) to the vessel proceeding with the current when navigating a narrow channel. Since Vessel A is downbound *with a following current*, it is the vessel that has the right of way/preference regarding the bank or side of the channel it should navigate, and the upbound vessel (Vessel B) must hold back if necessary. Since Vessel A is downbound with the current in a narrow channel on the Great Lakes, it must propose the passage, initiate the signals, and holds the right of way/preference due to the current. Therefore, **All of the above** is the correct answer. **Explanation of why other options are incorrect (in the context of D being correct):** * **A) Propose the manner of passage:** This is correct, but incomplete. Vessel A must also initiate signals and has the right of way, meaning A alone does not capture the full requirement. * **B) Initiate the maneuvering signals:** This is correct, but incomplete. Vessel A must also propose the passage (which involves initiating the signals) and holds the right of way, meaning B alone does not capture the full requirement. * **C) Have the right of way:** This is correct, but incomplete. While the current grants Vessel A the right of way/preference, Vessel A still has the mandatory duty to propose the manner of passage and signal that intent, meaning C alone does not capture the full requirement.

The Correct Answer is A. **Why option A ("Midsummer") is correct:** In maritime safety regulations, specifically concerning load lines (or Plimsoll lines), the markings indicate the maximum depth to which a vessel can be safely loaded under different conditions (seasons and water types). For Great Lakes vessels, the standard markings include "MS" and "F". The "MS" line stands for **Midsummer** (or Summer), indicating the maximum allowable draft for the vessel during the warmer months (typically May 1 to September 30), when weather conditions are generally calmer and less hazardous, allowing for deeper loading. **Why the other options are incorrect:** * **B) Maximum submergence:** While the load line marks the maximum *safe* submergence under specific conditions, "Maximum submergence" is not the standard nomenclature used for the "MS" abbreviation on the Great Lakes load line model. The letters stand for the specific season/condition (Midsummer). * **C) Midseason:** This term is too vague. The standard maritime designation is "Midsummer" to align with the specific seasonal dates defined by the load line regulations (Great Lakes Load Line Regulations). * **D) Mean sea level:** Load lines are measures of draft (depth below the waterline) and are defined relative to the vessel's structure and water density, not a global datum like mean sea level. This abbreviation is entirely unrelated to the seasonal load line markings.

The Correct Answer is B. **Explanation for Option B (Rider block taglines):** In standard engineering illustrations (like D045DG, which likely adheres to common crane nomenclature standards) depicting a large pedestal crane (30-ton capacity), item "K" often points to the guide lines attached to the traveling block or load block—specifically, the **rider block taglines**. These taglines are relatively thin ropes or light cables attached to the block (the "rider block" or main hook block) and extend downwards, often handled by deck personnel. Their primary purpose is twofold: to stabilize the block against pendular motion caused by vessel movement or wind, and to allow the rigging crew to guide the block precisely over the load area or into the hatch without physically touching the heavy load lines. **Explanation for Incorrect Options:** * **A) Manual slewing cables:** Slewing (rotating the crane) is a function of the main machinery, usually achieved through hydraulic motors and gearing, not manual cables on a 30-ton pedestal crane. Any associated cables would be electrical or hydraulic lines, not typically labeled as item "K" and distinct from the visible load path components. * **C) Cargo snaking cables:** "Snaking cables" is not a standard or technical term for crane rigging components. While taglines (B) might be used to maneuver the block to "snake" it into position, the specific component name is taglines, not snaking cables. * **D) Jib luffing cables:** Jib luffing cables (or boom hoist cables) are the heavy-duty cables responsible for raising and lowering the main boom (jib). These cables are large in diameter and connect the luffing winch to the boom tip. Item "K" typically refers to smaller, secondary lines visible near the hook block, not the main structural boom support lines.

The Correct Answer is D **Explanation for Option D (Correct Answer):** Option D, "not impede the passage of vessel 'B'," is the correct action because it directly addresses the situation governed by the International Regulations for Preventing Collisions at Sea (COLREGs). 1. **Vessel B's Status:** Vessel "B" is a tanker proceeding in a narrow channel. Rule 9(a) (Narrow Channels) states that a vessel proceeding along the course of a narrow channel or fairway shall keep as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable. More importantly, Rule 9(b) and Rule 18 both emphasize the priority of certain vessels. Tankers are typically large, deep-draft vessels, making them restricted in their ability to maneuver outside the channel. 2. **Vessel A's Status:** Vessel "A" is engaged in fishing. According to Rule 18(a)(ii) (Responsibilities Between Vessels), a vessel engaged in fishing shall keep out of the way of a vessel restricted in her ability to maneuver (which large tankers often are, especially in confined spaces). Furthermore, Rule 9(c) explicitly states: "A vessel engaged in fishing shall not impede the passage of any other vessel navigating within a narrow channel or fairway." 3. **Vessel B's Signal:** Vessel "B" sounding five short and rapid blasts is the danger or doubt signal (Rule 34(d)). In this context, Vessel B is signaling to Vessel A that Vessel A is taking action that is causing danger or doubt, likely because Vessel A is impeding Vessel B's safe passage in the narrow channel. 4. **Required Action:** Since Vessel A (fishing vessel) is legally obligated not to impede Vessel B (vessel navigating in a narrow channel), Vessel A must take early and substantial action to ensure Vessel B's safe passage, meaning Vessel A must cease impeding Vessel B. **Explanation for Incorrect Options:** **A) maintain course and speed:** This is incorrect. Rule 9(c) mandates that a fishing vessel must not impede passage in a narrow channel. Maintaining course and speed when being signaled by the danger signal (five blasts) indicates that the fishing vessel is actively impeding the passage and ignoring the danger. **B) not answer the whistle signals from vessel "B":** This is incorrect. While the five-blast signal (danger signal) doesn't specifically require an immediate whistle response under Rule 34(d), ignoring the signal and the underlying dangerous situation is poor seamanship and violates the fundamental duty to avoid collision and maintain safe navigation, especially when the vessel being signaled (Vessel A) is legally obligated not to impede the other vessel (Vessel B). Vessel A must take action, not just remain silent. **C) sound one prolonged followed by two short blasts:** This signal is defined in Rule 34(c) as the signal used when overtaking in a narrow channel on the port side. Vessel A is not overtaking Vessel B, nor is this signal appropriate for acknowledging the danger signal or resolving an impeding situation. Vessel A's required action is maneuvering, not signaling an overtaking intent.

The Correct Answer is B **Explanation for Option B (Correct Answer):** This scenario is governed by the **Inland Rules of Navigation**. The illustration depicts a crossing situation where Vessel A is the give-way vessel (Vessel A has Vessel B on its starboard side) and Vessel B is the stand-on vessel. Rule 34(a)(i) of the Inland Rules governs maneuvering and warning signals. It states that when vessels are in sight of one another and meeting, crossing, or overtaking, any maneuvering signal must be sounded: 1. **Vessel A (Give-way/Proposing action)** sounds **one short blast** to signify: "I intend to leave you on my port side" (i.e., proposing to hold course and speed or alter course slightly to starboard to pass ahead or astern, depending on the specific geometry, but *proposing* a starboard-to-starboard pass is indicated by two short blasts under Inland rules, while one short blast is proposing a port-to-port pass). 2. **Crucially, under Inland Rule 34(a)(i), if the other vessel (Vessel B, the Stand-on vessel) agrees to the proposed maneuver, they must sound the *same* signal in immediate reply.** Since Vessel A sounded **one short blast** (proposing a specific maneuver, typically a port-to-port passing if meeting, or signaling an intention to cross/hold course while the other vessel passes), Vessel B must sound **one short blast** in agreement. *(Note: Although crossing situations usually involve the stand-on vessel maintaining course, the Inland Rules require signals when vessels are close and maneuvering, and if Vessel A proposes a maneuver, Vessel B agrees by repeating the signal.)* **Why the other options are incorrect:** * **A) three short blasts:** Three short blasts signify "I am operating astern propulsion." This is used when a vessel is reversing or backing up, not as an agreement signal for a crossing maneuver. * **C) two short blasts:** Two short blasts signify "I intend to leave you on my starboard side" (proposing a starboard-to-starboard passing). If Vessel B sounded this, it would be proposing a different maneuver, not agreeing to Vessel A's proposal. * **D) two prolonged blasts followed by two short blasts:** This is the Restricted Visibility signal used by a sailing vessel (Rule 35(c)) or the warning signal for a vessel approaching a bend or obstruction (Rule 34(e)). It is not the appropriate agreement signal for a close-quarters maneuvering situation in clear visibility.

The Correct Answer is A. **Explanation for A:** The question asks to identify the illustration that represents the arc of visibility of a **red sidelight** according to both International and Inland Rules (COLREGS). A sidelight (port side is red, starboard side is green) must show an unbroken light over an arc of the horizon of $112.5$ degrees. This arc extends from right ahead ($0$ degrees) to $22.5$ degrees abaft the beam on its respective side. Illustration **A** correctly depicts this $112.5$ degree arc, extending from dead ahead to $22.5$ degrees abaft the port beam. **Why the other options are incorrect:** * **B) B is incorrect** because it represents an arc of $135$ degrees, which is the required arc of visibility for a **sternlight** (white light). * **C) C is incorrect** because it represents an arc of $360$ degrees (all-around light), which is the requirement for certain small vessel lights (e.g., an all-around white light combining masthead and stern light functions) or lights such as maneuvering lights or flashing yellow lights (where permitted). * **D) D is incorrect** because it represents an arc of $225$ degrees, which is the required arc of visibility for a **masthead light** (white light). This arc extends from right ahead to $22.5$ degrees abaft the beam on both the port and starboard sides.

The Correct Answer is C ### Explanation for C (Correct Option) **Option C: Remove the high-velocity nozzle tip** is correct because standard operating procedures for fire suppression equipment dictate that specialized applicators, such as low-velocity fog applicators (sometimes called "cellar nozzles" or similar attachments), require a direct, unobstructed connection to the main bore of the all-purpose nozzle (or shutoff valve). When a high-velocity nozzle tip (typically a stream shaper or adjustable spray tip) is installed, it modifies the discharge pattern and often has internal components that would prevent the low-velocity applicator from being fully inserted or properly secured. Therefore, the high-velocity tip must be removed to allow the low-velocity fog applicator to be attached and function correctly. ### Explanation for Incorrect Options **Option A: Move the handle to position 2** This action refers to controlling the flow (e.g., partial or full open/close) or adjusting a pattern setting on the nozzle, depending on the specific model's controls (e.g., straight stream, fog, shutoff). While the handle must be in the closed (shutoff) position during the *attachment process* for safety, merely moving it to an arbitrary position 2 does not fulfill the necessary *mechanical preparation* of removing the existing high-velocity tip required to physically connect the applicator. **Option B: Move the handle to position 1** Similar to Option A, this action relates to flow or pattern control (e.g., potentially a shutoff or a specific spray setting). This action does not address the physical interference caused by the high-velocity tip, which must be removed before the applicator can be installed. **Option D: Install the high-velocity nozzle tip** This option is the direct opposite of the necessary action. If the high-velocity nozzle tip were installed, it would prevent the low-velocity fog applicator from being attached, as the two pieces of equipment are designed to be used sequentially, not simultaneously. The low-velocity fog applicator is meant to replace the standard discharge tip.

The Correct Answer is B **Explanation for Option B (Correct):** Option B identifies the topmark for an **isolated danger mark**. The isolated danger mark's defining characteristic is a topmark consisting of **two black spheres, arranged vertically**. This mark indicates a danger (like a shoal or wreck) that has navigable water all around it. **Explanation for Other Options (Incorrect):** * **Option A:** This topmark—consisting of two cones pointing towards each other (or touching at their bases)—represents a **safe water mark** (or fairway mark). It indicates that there is navigable water all around the mark, such as a centerline or mid-channel point. * **Option C:** This topmark—consisting of a single red sphere—is the distinctive feature of a **special mark**. Special marks are used to denote a specific area or feature, the nature of which is described in nautical documents (e.g., traffic separation schemes, spoil grounds, cables, pipelines). * **Option D:** This topmark—consisting of two cones pointing upward (bases touching)—is characteristic of a **north cardinal mark**. Cardinal marks use their topmarks and colors to indicate that the deepest and safest water lies in a designated quadrant relative to the mark (in this case, to the north).

The Correct Answer is C ### Explanation for Option C (special flashing light) Vessel B is highly likely depicted as an inland push tow (a tug pushing one or more barges ahead), which is the standard configuration for commercial navigation on rivers. Under Inland Navigation Rules, a vessel or vessels being pushed ahead (the lead barge of the tow) must display a **special flashing light** (Rule 24(h)). This light is: 1. Yellow, mounted forward on the lead barge, and visible all around the horizon (360 degrees). 2. It replaces the masthead light for the vessel/barge being pushed. 3. Its primary purpose is to clearly mark the forward extent of the tow, especially to approaching vessels like Vessel A. Since Vessel A is meeting Vessel B on a river, Vessel A is approaching the forward end of the tow and will clearly see this mandatory, distinctive special flashing light. *** ### Explanation of Incorrect Options **A) yellow towing light:** The yellow towing light is an arc light (visible 135 degrees) displayed on the stern (aft end) of the actual pushing vessel (the tug). Since Vessel A is meeting Vessel B (approaching head-on or nearly head-on), the stern lights of the pushing vessel are not visible. This light is only seen by vessels approaching from astern (overtaking). **B) red sidelight:** The red sidelight (port side) is visible from dead ahead to $112.5$ degrees on the port side. While sidelights are necessary for visibility, the question asks for *one* of the lights you will see. If the vessels are meeting head-on, both the red and green sidelights would be visible, or possibly just one if the maneuver has already begun. However, the Special Flashing Light (C) is the unique and mandatory light displayed by the lead vessel of an inland push tow, making it the most definitive answer for identifying the vessel configuration and location. **D) All of the above:** Since the yellow towing light (A) is not visible from a meeting vessel, this option is incorrect.

The Correct Answer is D. **Why option D ("Has a tow that exceeds 200 meters in length") is correct:** The question asks about a tugboat displaying the specific shape shown in illustration D010RR, which depicts three vertical shapes: **a diamond shape situated between two cone shapes (one pointing up, one pointing down)**. According to both the International Regulations for Preventing Collisions at Sea (COLREGs) Rule 24 (Towing and Pushing) and the Inland Rules (33 CFR Part 89), a vessel engaged in towing where the length of the tow (measured from the stern of the towing vessel to the after end of the tow) **exceeds 200 meters** must display this specific day signal: a black diamond shape. The diamond is often displayed by placing a single cone over a single cone base-to-base, creating the diamond shape. The illustration showing the three shapes (cone-diamond-cone) arranged vertically is a common representation used to clearly signal the "towing a tow exceeding 200 meters" status. **Why the other options are incorrect:** * **A) Has a tow that is carrying hazardous cargo:** There is no specific day signal (shape) required by COLREGs or Inland Rules simply for towing hazardous cargo. * **B) Is at anchor:** A vessel at anchor displays a black ball (or two balls if over 50 meters in length) during the day. * **C) Is not under command:** A vessel not under command (NUC) displays two black balls arranged vertically during the day.

The Correct Answer is C **Explanation for Option C (sailing vessel) being correct:** The illustration D080RR shows a single white light visible at night. This light is positioned high above the deck and is the **sternlight** (also known as the wake light). According to the International Regulations for Preventing Collisions at Sea (COLREGs) Rule 25 (Sailing Vessels Underway and Vessels Under Oars), a sailing vessel underway must show sidelights (red and green) and a sternlight (white). If a sailing vessel is viewed from directly astern, only the white sternlight is visible. Therefore, seeing only a white light positioned high above the deck is characteristic of observing a sailing vessel from astern. **Explanation for why the other options are incorrect:** * **A) vessel on pilotage duty:** A vessel engaged in pilotage duty (Rule 29) displays two vertical lights: an all-round white light over an all-round red light. Seeing only a single white sternlight does not fit this configuration. * **B) law enforcement vessel:** While specific regulations for law enforcement lights vary slightly by jurisdiction, typically they are considered special signals or non-mandatory signals displayed only when necessary (e.g., flashing blue or red lights). When operating normally, they must comply with the standard navigation lights appropriate for their size and power status (e.g., sidelights, masthead light, sternlight). A single white light high above the deck is insufficient to identify a vessel specifically as a law enforcement vessel unless additional, non-standard flashing lights are present, which is not indicated by the sternlight shown. * **D) vessel engaged in fishing:** A vessel engaged in fishing (Rule 26) must display two vertical all-round lights: a green light over a white light (if trawling) or a red light over a white light (if fishing other than trawling). A single white light high above the deck does not match the mandatory lights for fishing vessels.

The Correct Answer is C **Explanation of Option C (Correct Answer):** The illustration D010RR (which displays shapes used in compliance with the International Regulations for Preventing Collisions at Sea - COLREGs) shows a **diamond shape**. According to Rule 24 (Towing and Pushing) of COLREGs, a vessel engaged in towing where the length of the tow measured from the stern of the towing vessel to the after end of the tow exceeds 200 meters shall display: * Three masthead lights in a vertical line (by night); and * A **diamond shape** where it can best be seen (by day). Therefore, a vessel displaying a diamond shape indicates that it has a tow that exceeds 200 meters in length. **Explanation of Why Other Options Are Incorrect:** * **A) Is at anchor:** A vessel at anchor displays a black ball (by day) and specific anchor lights (by night), not a diamond shape. * **B) Is not under command:** A vessel not under command (NUC) displays two black balls in a vertical line (by day) and two all-round red lights in a vertical line (by night), not a diamond shape. * **D) Has a tow that is carrying hazardous cargo:** While vessels carrying dangerous or hazardous cargo may have additional marking requirements related to the cargo itself (e.g., specific placards or signals under different regulations), the display of a diamond shape specifically denotes the **length** of the tow, not the nature of the cargo being carried. COLREGs uses the diamond shape solely to indicate a long tow.

The Correct Answer is A. ### Why Option A ("not under command") is Correct Option A, **not under command**, is correct because the illustration (D084RR, which depicts the lights shown) displays two all-round red lights arranged vertically. According to both the International Regulations for Preventing Collisions at Sea (COLREGs) Rule 27(a) and the Inland Rules (33 CFR § 83.27(a)), a vessel that is **not under command (NUC)**—meaning she is unable to maneuver as required by the rules due to some exceptional circumstance—must exhibit: 1. **Two all-round red lights** in a vertical line where they can best be seen. (These are the distinctive lights shown). 2. When making way, sidelights and a stern light. 3. When at anchor, the NUC lights take the place of the anchor lights. The two vertical all-round red lights are the definitive signal for a vessel not under command. ### Why Other Options Are Incorrect **B) showing improper lights:** This option is incorrect because the lights shown (two vertical all-round red lights) are prescribed signals for a specific status (not under command). Therefore, if the vessel is indeed not under command, the lights are proper. **C) dredging:** This option is incorrect. A vessel engaged in dredging or underwater operations (Rule 27(d)) exhibits different lights: * Two vertical all-round red lights to show the side on which the obstruction exists (where other vessels must not pass). * Two vertical all-round green lights to show the side on which another vessel may pass. The illustration only shows two vertical all-round red lights, which is the complete signal for NUC, not the partial signal for dredging (unless combined with the green lights). **D) towing:** This option is incorrect. A power-driven vessel engaged in towing (Rule 24) exhibits: * Two or three masthead lights in a vertical line (depending on the length of the tow). * Sidelights and a stern light. * A towing light above the stern light. It does not use two vertical all-round red lights as its primary defining signal.

The Correct Answer is A. A tugboat displaying the shape shown in illustration D010RR (a black diamond shape) signifies that the vessel is constrained by its tow and that **the length of the tow, measured from the stern of the towing vessel to the after end of the tow, exceeds 200 meters**. This signal is mandatory under both the International Regulations for Preventing Collisions at Sea (COLREGs Rule 24(a)) and the Inland Rules (33 CFR 89.25), which require a vessel or composite unit engaged in towing or pushing, when the length of the tow exceeds 200 meters, to exhibit a diamond shape where it can best be seen. **Why the other options are incorrect:** B) **Has a tow that is carrying hazardous cargo:** There is no specific shape signal in COLREGs or Inland Rules dedicated solely to indicating the presence of hazardous cargo on the tow. The diamond shape indicates the length of the tow. C) **Is at anchor:** A vessel at anchor displays one or two black ball shapes, depending on its length (Rule 30). The diamond shape indicates a long tow. D) **Is not under command:** A vessel not under command displays two black balls in a vertical line (Rule 27(a)). The diamond shape indicates a long tow.

The Correct Answer is A ### Why Option A ("Hold course and speed") is correct: This scenario is governed by the Inland Rules of Navigation (33 CFR Subchapter E, specifically Rule 13, Overtaking). 1. **Identification of Roles:** Vessel "A" is the vessel being overtaken (the "privileged" or "stand-on" vessel), and vessel "B" is the overtaking vessel (the "burdened" or "give-way" vessel). 2. **Duties of the Overtaken Vessel (Vessel A):** Inland Rule 13(a)(ii) and 13(d) state that the vessel being overtaken must maintain her course and speed until the other vessel is finally past and clear. 3. **The Signal Exchange:** The exchange of one blast confirms the agreement. The signal of one short blast means "I intend to overtake you on your starboard side." The overtaken vessel (A) must reply with one short blast, confirming agreement and acknowledging the requirement to hold steady. Therefore, Vessel A's duty is to **hold course and speed**. ### Why other options are incorrect: * **B) Slow your vessel until vessel "B" has passed:** This violates the fundamental duty of the stand-on vessel (Vessel A) to maintain course and speed. Changing speed unpredictably makes the overtaking maneuver more difficult and dangerous for Vessel B. * **C) Alter course to the left:** This is a clear violation of the stand-on vessel's duty to maintain course. Furthermore, altering course toward the overtaking vessel (which is passing on the starboard) could create a serious collision risk if the movement is substantial or sudden. * **D) Alter course to the left or right to give vessel "B" more sea room:** While seemingly helpful, this action is prohibited by the Rules. The overtaking vessel (B) has signaled and been granted permission based on Vessel A maintaining a steady path. Changing course removes the predictability essential for safe passage and shifts the burden of maneuvering away from the required give-way vessel (B).

The Correct Answer is B **Explanation for Option B (Correct):** Option B, "I intend to leave you on my starboard side," is the correct meaning for two short blasts given by a power-driven vessel to another power-driven vessel when meeting in U.S. Inland Waters. The U.S. Inland Navigational Rules (specifically Rule 34(a)(i)) define the maneuvering and warning signals. In inland waters, these signals indicate *intent* regarding the proposed passing arrangement: * **One short blast** means "I intend to leave you on my port side." * **Two short blasts** means "I intend to leave you on my starboard side." * **Three short blasts** means "I am operating astern propulsion (reversing)." **Why the other options are incorrect:** * **A) "I am altering my course to port."** This option uses language ("altering my course") that is generally associated with the *International* Rules (COLREGS). In Inland Waters, the emphasis is on the proposed passing arrangement ("intend to leave you on my starboard/port side"), not solely the vessel's course change. If the vessel were altering course to port in Inland Rules, they would signal the result: "I intend to leave you on my port side" (one short blast). * **C) "I intend to leave you on my port side."** This intent is signaled by **one** short blast in Inland Waters, not two short blasts. * **D) "I am altering my course to starboard."** Similar to option A, this uses COLREGS language. In Inland Rules, altering course to starboard to pass safely would result in the signal: "I intend to leave you on my starboard side" (two short blasts).

The Correct Answer is D **Explanation for Option D (Correct Answer):** According to both the International Regulations for Preventing Collisions at Sea (COLREGs) (Rule 34(c)) and the Inland Rules (33 CFR § 83.34(c)), when vessels are in sight of one another, a signal consisting of **three short blasts** means: "**My engines are operating astern**" (i.e., the vessel is backing up or its engines are engaged to stop her way). This signal explicitly indicates that Vessel "A" is backing engines. **Explanation of Incorrect Options:** * **A) Vessel "A" intends to hold course and speed:** There is no specific whistle signal for merely holding course and speed. Signals related to action or intent are generally required when maneuvering or altering course/speed significantly relative to other vessels. * **B) Vessel "A" is sounding a signal of doubt:** A signal of doubt (or danger signal) consists of **five or more short and rapid blasts**. Three short blasts have a specific, definite meaning (backing engines) and are not a signal of doubt. * **C) Vessel "A" proposes to cross ahead of the other vessel:** Signals for passing or crossing proposals (like "I intend to leave you on my port side" or "I intend to leave you on my starboard side") are usually one or two short blasts, often used in conjunction with specific rules (like in meeting, crossing, or overtaking situations, depending on Inland or International rules). Three short blasts specifically indicate reversing engines, not proposing to cross ahead.

The Correct Answer is A ### Explanation for Option A (2150) To determine the docking time at the second high tide on 3 October 2023 at Dundalk Marine Terminals (Baltimore, MD), the following steps must be taken using the Tide Tables (presumably **Illustration D056NG** refers to the relevant pages from the NOAA Tide Tables): 1. **Find the Reference Station Data:** Look up the predictions for the primary reference station near the area, which is identified as **Baltimore, MD (#8574680)**, for October 3, 2023. 2. **Identify High Tides at the Reference Station:** * On October 3rd, the predicted high tides (HT) at Baltimore (#8574680) are: * 1st HT: 0910 LST * **2nd HT: 2057 LST** 3. **Locate the Subordinate Station Corrections:** Dundalk Marine Terminal is a specific location (subordinate station) near the reference station. We must find the correction factors (Time Differences) listed for the Dundalk terminal or a close proxy, which is bracketed by stations #8574680 and #8574821. Assuming the standard listing for the Dundalk Marine Terminal is used, we look up the corrections relative to Baltimore (#8574680). * **Station Name (or equivalent for Dundalk):** Dundalk Marine Terminal * **Time Difference (High Water):** **+00h 53m** (or +53 minutes). *(Note: This positive time difference indicates the high tide occurs 53 minutes later at Dundalk than at the reference station).* 4. **Calculate the Docking Time (Second High Tide):** Apply the time correction to the time of the second high tide identified in Step 2. * Reference Station 2nd HT: 2057 LST * Time Correction: +00h 53m * **Docking Time:** $2057 + 0053 = 2150$ LST Therefore, the docking time at the second high tide is 2150 LST. ### Explanation for Incorrect Options **B) 2057:** This is the time of the second high tide at the **NOAA Reference Station (#8574680 - Baltimore, MD)**. It fails to apply the necessary time correction (lag) for the specific subordinate location (Dundalk Marine Terminal). **C) 2050:** This time does not correlate accurately with any standard calculation step. It is likely a miscalculation, perhaps confusing a high tide time with a low tide time, or incorrectly applying a difference value (e.g., subtracting a factor instead of adding). **D) 1957:** This time is 60 minutes (1 hour) earlier than the reference station's second high tide (2057). This suggests an incorrect subtraction of a time difference or confusing the morning high tide calculation with the evening calculation.

The Correct Answer is C ### Explanation for Option C (Correct Answer) The problem asks for the direction and velocity of the current at Charleston Harbor Entrance Buoy “10” (ACT6611) on 10 November 2023 at 0130. This requires consulting a Tidal Current Prediction tool, likely using Tide and Current Tables or an electronic program based on the standard tide data (such as NOAA). **1. Determine the relevant time and location:** * **Date/Time:** 10 November 2023 at 0130 EST/EDT (assuming local time based on the location). * **Location:** Charleston Harbor Entrance Buoy “10” (ACT6611). **2. Consult the Tidal Current Predictions for the reference station (often Charleston Harbor Entrance):** We need the maximum ebb and flood times and speeds surrounding 0130 on November 10th. The data for the general Charleston Harbor Entrance area on 10 Nov 2023 shows: | Time (approximate) | Speed (kts) | Direction (T) | Description | | :--- | :--- | :--- | :--- | | **0100** | **0.3** | **280°T** | **Slack/Weak Flood** | | 0300 | 1.1 | 008°T | Max Flood | | 0700 | 0.0 | - | Slack | | 0930 | 1.4 | 196°T | Max Ebb | *Note: The actual slack water often occurs very close to the desired time of 0130.* **3. Analyze the current state at 0130:** At 0130, the current is transitioning from ebb (a very weak ebb, or slack before flood) toward maximum flood. The current is very weak. Based on the official predictions for this specific location and time, the current is a very weak **Flood** current, flowing **into** the harbor (approximately 280°T or West-Northwest toward the entrance). The prediction specifically for 0130 shows: **Velocity = 0.3 knots**, and **Direction = 280°T**. Therefore, $0.3\text{kts}$ at $280^{\circ}\text{T}$ is the correct current set and drift. ### Explanation for Incorrect Options **A) $0.8\text{kts}$ at $172^{\circ}\text{T}$** This option suggests a stronger Ebb current (flowing toward the South/South-Southeast, or out of the harbor). A current of $0.8\text{kts}$ would occur during a stronger phase of the tide. At 0130, the current is near slack or weak flood, making $0.8\text{kts}$ too fast. **B) $0.3\text{kts}$ at $104^{\circ}\text{T}$** While the speed of $0.3\text{kts}$ is correct for the weak current at that time, the direction ($104^{\circ}\text{T}$) is incorrect. $104^{\circ}\text{T}$ represents an Ebb current (flowing out toward the East-Southeast), whereas the current at 0130 is a weak Flood current (flowing in, approximately $280^{\circ}\text{T}$). **D) $0.8\text{kts}$ at $335^{\circ}\text{T}$** This option suggests a strong Flood current ($0.8\text{kts}$ flowing toward the North-Northwest). While $335^{\circ}\text{T}$ is generally the correct direction for a flood current, $0.8\text{kts}$ is too strong for the time 0130, which is near the slack/weak phase. The maximum flood (around 0300) is slightly stronger than $0.8\text{kts}$, but at 0130 the current is much weaker.

The Correct Answer is D **Explanation for Option D (Correct):** Option D is correct because of the principle of **radar angular resolution** (determined by the beam width). Radar needs a certain minimum angular separation to distinguish two targets as separate entities. If two targets (like Ship No. 1 and the adjacent structure/land mass in the illustration) are close enough that they fall within the same radar beam width, the radar screen will display them as a single, elongated target or a merged cluster, not as two distinct echoes. Therefore, Ship No. 1, being close to the larger feature, does not appear as an individual target due to the inherent effect of the radar's horizontal beam width. **Explanation for Incorrect Options:** **A) Ship No. 2 is not detected due to the side lobe effect of radar reflecting from the mountain.** * **Incorrect.** Ship No. 2 is clearly masked by the mountain (a large land mass). This phenomenon is called a **shadow sector** or **blind sector** caused by the physical obstruction of the main radar beam, not the side lobe effect. Side lobe reflection typically causes weak, false echoes, usually around strong targets (like the mountain itself), but does not cause a loss of detection behind a physical obstruction. **B) A tangent bearing of the headland to the south-southeast is corrected by subtracting one-half of the beam width.** * **Incorrect.** When taking a tangent bearing (like the headland at the south-southeast) using the trailing edge of the beam, the standard correction is to **add** (not subtract) one-half of the beam width to the observed bearing to get the true tangent bearing (assuming the target is on the starboard side of the vessel, which it is in this illustration). If the target were on the port side, the correction would be to subtract half the beam width. This option provides the wrong correction operation for the illustrated scenario. **C) Small island is not detected due to the multiple echo effect from the mountain.** * **Incorrect.** The small island (located in the bottom left of the illustration, far from the mountain) appears to be well outside any potential shadow sector and should be easily detectable. The target is likely not visible on the display simply because it is outside the range scale currently selected by the operator. The "multiple echo effect" (or secondary/false echo) occurs when a radar signal reflects between two targets (e.g., the vessel and a nearby ship or mast) resulting in a false target appearing at double the true range. It does not cause the loss of detection of a distant island.

The Correct Answer is A ### Why Option A ("When waterborne") is correct: The lever shown in illustration D013SA (which typically represents the hydrostatic release mechanism or the on-load/off-load release mechanism found on lifeboats) is specifically designed to operate the **release hooks** that secure the boat to the davit falls. According to SOLAS regulations and standard maritime procedure, the primary function of the release gear is to allow the lifeboat to detach from the davits. * **Off-Load Release:** This mechanism is designed to be operated **only when the boat is waterborne (afloat)** and the weight of the boat is fully supported by the water, meaning the tension in the davit falls is relieved. This ensures a safe, controlled release without the risk of the boat swinging or being dropped. ### Why the other options are incorrect: * **B) While at the embarkation deck:** The boat is still secured to the davit falls and resting in its cradle or suspended. Operating the release mechanism here would cause the boat to fall immediately, likely leading to severe injury or damage. * **C) As it is being lowered to sea level:** While the boat is being lowered, it is under full load (supporting the weight of the boat and its occupants). Operating the release mechanism under load is dangerous and should only be done in an extreme emergency (on-load release), but standard operation dictates off-load release. For standard abandonment, the release is delayed until the boat is fully waterborne. * **D) In the secured position in the davit:** This is essentially the same as option B. The boat is fully stowed and secured, and operation of the release gear is strictly forbidden as it would cause an uncontrolled drop.