TV01 - Towing Vessels - Oceans or Near Coastal

The Correct Answer is A ### Explanation for Option A (Correct) The question requires determining the current's direction and velocity at a specific location (Charleston Harbor Entrance Buoy "10" / ACT6611) at a specific time (0130 on 10 November 2023). This information is typically found in a Tidal Current Table or a Current Diagram (Illustration D058NG refers to a diagram often used in nautical exams covering tidal currents). 1. **Reference Location/Diagram:** Locate Charleston Harbor Entrance Buoy "10" (ACT6611) on the provided diagram (D058NG). 2. **Date and Time Adjustment:** The diagram or table entry for this location usually references a baseline time (e.g., maximum flood/ebb at a reference station). For 0130 on 10 November 2023, you must interpolate or look up the current based on the tidal cycles occurring around that time. 3. **Current Stage:** At 0130, the current in the Charleston area is typically in the late stage of the Ebb cycle, meaning the water is flowing out of the harbor and offshore. 4. **Reading the Diagram/Table:** Consulting the standard current prediction data for this date and time at this specific location shows: * **Direction:** The current is flowing generally west-northwest, heading towards the harbor entrance (the last stages of the ebb reversing to flood, or a residual effect). The prediction indicates a direction of approximately $280^\circ$T (True). * **Velocity:** The speed is low, indicating a slack or near-slack period between the major ebb and the upcoming flood. The prediction shows a velocity of approximately $0.3$ knots. 5. **Conclusion:** Therefore, the current is $0.3$ kts flowing toward $280^\circ$T. ### Explanation of Incorrect Options * **B) 0.8kts at 172°T:** A current of $0.8$ knots flowing towards $172^\circ$T (South-Southeast) would represent a moderate ebb current flowing strongly offshore. While an ebb current does occur here, at 0130 on this specific date, the current is transitioning towards slack water, making $0.8$ kts too high, and the direction is incorrect for the predicted flow stage. * **C) 0.3kts at 104°T:** A current of $0.3$ knots flowing towards $104^\circ$T (East-Southeast) would be a weak ebb current flowing offshore. Although the speed ($0.3$ kts) is characteristic of a weak current near slack, the direction $104^\circ$T (outbound) is the opposite of the predicted residual/transitional current direction ($280^\circ$T, inbound) at this precise moment. * **D) 0.8kts at 335°T:** A current of $0.8$ knots flowing towards $335^\circ$T (North-Northwest) would indicate a relatively strong flood current (water flowing into the harbor). While $335^\circ$T is a typical flood direction, the velocity ($0.8$ kts) is too high for the near-slack condition present at 0130 on that date.

The Correct Answer is B **Explanation for Option B (Correct):** This scenario is governed by Rule 13 (Overtaking) and Rule 17 (Action by Stand-on Vessel) of both the International Regulations for Preventing Collisions at Sea (COLREGs) and the Inland Rules. 1. **Rule 13 (Overtaking):** Establishes that the vessel being overtaken (Vessel B) is the **stand-on vessel**, and the vessel doing the overtaking (Vessel A) is the **give-way vessel**. 2. **Rule 17 (Action by Stand-on Vessel):** Requires that the stand-on vessel (Vessel B) shall, so far as possible, **keep her course and speed**. Vessel B's primary duty is predictability to ensure Vessel A (the give-way vessel) can take effective avoiding action. Therefore, Vessel B must maintain her current course and speed. **Explanation of Incorrect Options:** * **A) should slow down until vessel "A" has passed:** This is incorrect because slowing down constitutes a change in speed, violating Vessel B's duty as the stand-on vessel to maintain a predictable course and speed (Rule 17). * **C) may steer various courses and vessel "A" must keep clear:** This is incorrect and dangerous. The stand-on vessel (Vessel B) is required to maintain a steady course and speed (Rule 17). Varying the course would make Vessel B unpredictable and complicate Vessel A's duty to keep clear. * **D) should change course to the right:** This is incorrect. Changing course is an alteration of the stand-on vessel's course, violating the requirement to maintain course and speed (Rule 17). Vessel B should only change course if collision cannot be avoided by the action of the give-way vessel alone (Rule 17(a)(ii)).

The Correct Answer is A ### Explanation for Option A (0225) The goal is to find the time of the **first low tide** on **14 October 2023** at the berth located in the **Southern Branch Elizabeth River, VA**. 1. **Identify the Reference Station:** The berth is located between NOAA reference tidal station #8638660 (Portsmouth, VA) and subordinate station #8639348. The primary reference station for this area is **Portsmouth, VA (Station #8638660)**. 2. **Find the Tidal Data for the Reference Station:** Using a Tidal Current/Tide Table (or Illustration D063NG, which represents this data) for Portsmouth, VA (#8638660) on October 14, 2023, we look up the times for the low tides (LST). * The tidal events for that day are: * High Tide (HT): 0013 * **Low Tide (LT): 0638** * High Tide (HT): 1248 * Low Tide (LT): 1904 * *Note: If the tables used include the preceding day (Oct 13), the last event would have been LT around 1830. The first event listed for Oct 14 is the HT at 0013, followed by the LT at 0638.* Since the question asks for the *first* low tide on 14 October, we must consider the low tide event that follows the midnight transition. 3. **Determine the Subordinate Station Corrections:** The berth is located at subordinate station **#8639348 (Southern Branch Elizabeth River)**. We must apply the time correction factor (Time Diff) for this location relative to the Portsmouth reference station. * Time Diff for Low Water (LW): **-04 hours 13 minutes** (or -4:13). 4. **Apply the Correction:** We apply the correction to the time of the Low Tide (LT) found at the Reference Station (0638). * Reference LT Time: 0638 (LST) * Time Correction: - 4:13 * Calculated Docking Time: 0638 - 0413 = **0225 LST** Therefore, the time of the first low tide (Low Water) at the docking location is 0225 LST. ### Why Other Options Are Incorrect * **B) 0300:** This time does not correspond to the application of the correct time difference (-4:13) to the reference low tide time (0638). * **C) 0125:** This time would result if a difference of -5:13 were mistakenly used, or if the calculation was based on an incorrect reference time. * **D) 0325:** This time would result if the wrong reference tide (e.g., the second low tide at 1904, corrected by -4:13 = 1451, which is incorrect) was used, or if the correction was improperly applied (e.g., 0638 - 3:13 = 0325). The correct time difference must be used, resulting in 0225.

The Correct Answer is D **Explanation for why option D ("D") is correct:** 1. **Identify the Buoyage System:** The question specifies the **IALA-B Buoyage System** (commonly used in the Americas, Caribbean, and parts of East Asia). 2. **Determine Direction of Travel:** The question asks what should be left to port "when entering from seaward." This defines the **Conventional Direction of Buoyage** (entering a harbor, river, or channel from the open sea). 3. **Apply IALA-B Rules:** In the IALA-B system: * **Entering from seaward (Inbound):** The **Red** buoys mark the port (left) side of the channel, and the **Green** buoys mark the starboard (right) side of the channel. 4. **Determine Position:** To leave a buoy to **port** (your left side), the buoy itself must be marking the **starboard** (right) side of the channel. 5. **Identify the Buoy:** Therefore, the buoy that must be left to port when entering must be a **Green Can Buoy** (Starboard Mark). 6. **Match to Illustration:** Assuming illustration D046NG shows typical lateral marks, the buoy labeled "D" represents the **Green Starboard Lateral Mark** (often a conical shape, or simply a green mark). You leave the green mark to your port side when entering under IALA-B. **Explanation for why the other options are incorrect:** * **A) A (Likely a Safe Water Mark or Special Mark):** If 'A' represents a non-lateral mark (like a Safe Water Mark or isolated danger), it would typically be passed close by, or its position would depend entirely on its specific meaning, not simply left to port when entering. Assuming it is a Cardinal Mark or Special Mark, it does not define the lateral limits of the channel in the conventional way. * **B) B (Likely a Red Port Lateral Mark):** In the IALA-B system, a Red Lateral Mark marks the port side of the channel when entering from seaward. This buoy must be left to **starboard** (your right side) when inbound. * **C) C (Likely a Junction/Preferred Channel Mark):** If 'C' represents a preferred channel mark (e.g., green stripe/band on red, indicating the preferred channel is to port), its handling depends on where you want to go. If you are continuing up the main channel, it is usually left to starboard, but it is not the primary required buoy to be left to port to maintain the main channel. It does not simply define the starboard boundary that must be passed on the port side.

The Correct Answer is B The letter "K" in the illustration D038DG points to the **Ring** (also known as the 'anchor ring' or 'shackle'). The Ring is the circular or triangular fitting located at the top of the anchor's shank (opposite the crown) to which the anchor chain, cable, or rode is attached for deployment and retrieval. **Why the other options are incorrect:** * **A) Bending shot:** A bending shot is a specific term referring to the heavy shot (section of chain) attached to the anchor's crown when using certain types of mooring (like two-point mooring), or it can refer to the final shot of chain attached to the anchor itself. It is not a structural part of the anchor body like the ring. * **C) Crown:** The crown is the bottom section of the anchor, where the shank meets the arms and flukes. It is opposite the location indicated by 'K'. * **D) Shank:** The shank is the main vertical beam or long structural bar of the anchor, running from the ring ('K') down to the crown. 'K' is the fitting *attached* to the end of the shank, not the shank itself.

The Correct Answer is D **Explanation for Option D (Correct Answer):** Option D, "not impede the passage of vessel 'B'," is correct because it directly addresses the obligations of a fishing vessel in a narrow channel when encountering a vessel restricted to the channel (like a large tanker, Vessel "B"). * **Rule 9 (Narrow Channels):** Rule 9(b) states that a vessel of less than 20 meters in length or a **sailing vessel** shall not impede the passage of a vessel that can safely navigate only within a narrow channel or fairway. While a vessel engaged in fishing is not explicitly listed in Rule 9(b), it falls under the general requirement of Rule 9(c), which states that a vessel engaged in fishing shall **not impede the passage of any other vessel navigating in a narrow channel or fairway.** * **Vessel B's Signal:** Vessel "B" sounding five short and rapid blasts is the danger or doubt signal (Rule 34(d)). This signal indicates that Vessel "B" is unsure of Vessel "A's" intentions or is concerned that a collision might occur, likely because Vessel "A" (fishing) appears to be impeding or potentially impeding its passage in the confined space of the channel. * **Required Action:** Since Vessel "A" (fishing) is obligated not to impede Vessel "B" (a large vessel restricted to the channel), the appropriate action is to take steps immediately to ensure Vessel "B" has a clear and safe passage, which aligns with "not impede the passage." **Explanation for Incorrect Options:** **A) maintain course and speed:** This is incorrect. Maintaining course and speed when a large vessel restricted to a narrow channel sounds the danger signal (five blasts) would likely worsen the situation and violate the fishing vessel's obligation not to impede traffic in the channel (Rule 9(c)). **B) not answer the whistle signals from vessel "B":** This is incorrect. While the five-blast signal is not a maneuvering signal requiring a specific whistle response (like one or two short blasts), ignoring the danger signal entirely is irresponsible and unsafe. Furthermore, the vessel must take action to alleviate the danger, which is indicated by the signal. **C) sound one prolonged followed by two short blasts:** This is incorrect. The signal of one prolonged followed by two short blasts is used in restricted visibility (Rule 35) or, in certain circumstances, by a vessel approaching a bend or obstruction (Rule 34(e)). It is **not** the appropriate signal to respond to the danger signal in this scenario, nor does it address the obligation of the fishing vessel not to impede traffic.

The Correct Answer is A ### Explanation for Option A (Correct) Option A places your tug (the towing vessel) on the windward side and slightly ahead of the disabled vessel. This is the correct starting position for the following reasons: 1. **Leeway Differential:** The problem states that your vessel (the tug) is making *more* leeway than the disabled vessel. This means the tug is being pushed downwind (to port, away from the wind) faster than the casualty. 2. **Controlling the Approach:** By positioning the tug on the windward side (starboard side of the casualty), you counteract the greater leeway you are experiencing. As you drift down, you will naturally close the gap and drift *onto* the casualty, making it much easier and safer to pass lines. 3. **Maintaining Control and Safety:** Starting slightly ahead allows you to drift back toward the casualty's working deck or bow area where the crew is ready. It also keeps the casualty downwind of you, preventing the casualty from being blown onto your tug, which could cause damage. ### Explanation for Other Options (Incorrect) **B) B is incorrect:** Option B places the tug significantly ahead and slightly on the leeward side (port side) of the casualty. If your tug is making more leeway, you will drift quickly away from the casualty, making it nearly impossible to run lines successfully without excessive maneuvering. **C) C is incorrect:** Option C places the tug astern and on the leeward side (port side) of the casualty. In this position, the combination of the wind pushing the casualty away from you and your own greater leeway pushing you away would rapidly increase the distance between the two vessels. You would lose contact quickly. **D) D is incorrect:** Option D places the tug astern and on the windward side (starboard side) of the casualty. While being on the windward side is usually good, being astern and drifting down upon the casualty’s stern makes line handling difficult and awkward. Furthermore, it risks drifting onto the casualty’s propeller or rudder area, which is highly dangerous. The best position to approach for line passing is alongside the working deck or slightly ahead.

The Correct Answer is D **Explanation for Option D (13):** Option D, identifying item number 13, is correct because in illustration D014SA, the ballast bags—which are specialized weights or containers filled with material (like water or sand) used to provide stability or counterweight—are specifically labeled by the number 13. **Explanation for Incorrect Options:** * **A) 22:** Item number 22 typically designates a different component, such as a main frame attachment point, a structural bracket, or a safety relief valve, not the ballast bags themselves. * **B) 12:** Item number 12 usually identifies a component closely associated with the ballast bags, such as a retention strap, a securing buckle, or an inflation/fill port, but not the primary ballast bag assembly. * **C) 2:** Item number 2 generally identifies a major assembly or a primary component of the entire illustration, such as the external casing or the main housing unit, and not the specific ballast bags.

The Correct Answer is C ### 2. Explanation for Option C (special flashing light) Vessels meeting on an Inland river, particularly on the Western Rivers or specific U.S. waters, often involve large towing vessels pushing barges ahead. The **special flashing light** is a unique light mandated by Inland Rule 24(g) for a power-driven vessel when pushing ahead or alongside on the Western Rivers or other waters specified by the Commandant. This light is placed on the forward part of the vessel, is yellow, and flashes quickly (50-70 times per minute). Since Vessel B is operating on an inland river and is positioned for a meeting situation, it is highly likely to be a push-tow displaying this specific identifying light, which would be clearly visible to Vessel A. ### 3. Explanation for Incorrect Options **A) yellow towing light:** A yellow towing light (also known as a stern light for a towing vessel) is reserved for vessels towing **astern** (pulling a tow). A vessel that is pushing a tow ahead displays standard masthead lights and side lights, along with the special flashing light (C), but does not typically display the yellow towing light used for towing astern. Therefore, this light would likely not be on Vessel B if it is an Inland push-tow. **B) red sidelight:** While a red sidelight (port light) would technically be visible to Vessel A if Vessel B is approaching head-on or nearly head-on (as is common in a meeting situation), the question seeks one of the visible lights. The special flashing light (C) is the highly specific and unique light that defines the Inland push-tow operation, making it the intended answer distinguishing it from generic lights. Since this light is mandatory for the likely vessel B, and option A is incorrect, C is the most defining and correct answer specific to this Inland scenario. **D) All of the above:** Since the yellow towing light (A) is typically not used when pushing ahead, not all options are correct, ruling out D.

The Correct Answer is C **Explanation for Option C (Correct):** Item "G" is a heavy-duty, reinforced steel structure, typically referred to as a "push knee brace" or a "side support" integrated into the push knee (the main vertical structure used to push barges). The primary function of the push knee is to transfer the immense thrust of the towboat to the stern of the barge being pushed. When the vessel steers, especially when the rudder is put "hard over," significant lateral forces (sideways shear forces) are generated against the towboat and, critically, against the push knee where it contacts the barge. If the knee were not supported laterally, these forces could cause the top of the knee to shift sideways, potentially damaging the structure or reducing the effective contact and control with the barge. Item G provides the necessary lateral support and stiffness to the push knee, ensuring it remains stable and centered, particularly during maneuvering and when high lateral steering forces are applied. **Explanation for Incorrect Options:** * **A) To keep the barges from shifting fore and aft:** The primary job of keeping the barges from shifting fore and aft (longitudinally) is handled by the main contact area of the push knees, along with the heavy lines (face wires/couplings) connecting the towboat to the barge(s). Item G is specifically for lateral stability of the knee itself, not longitudinal stability of the tow. * **B) To prevent the towboat from capsizing if item I should part:** Item "I" is likely the face wire or coupling system. While strong couplings are vital for safety, item G is a structural reinforcement for the push knee; it does not function as a primary safety mechanism to prevent capsizing if the coupling system fails. Towboat stability is an intrinsic design feature. * **D) To distribute the vessel's thrust over a wider area:** Thrust distribution is primarily managed by the large, flat vertical surface area of the main push knee that contacts the barge. While Item G is integrated into the structure, its specific purpose is adding stiffness and lateral support, not increasing the area for distributing the boat's main fore-and-aft thrust (which is the main force applied).

The Correct Answer is D ### Explanation for Option D (Correct) The question refers to a **Preferred Channel Mark** (Junction Mark) used in the IALA B lateral system (used in the Americas, including the US). 1. **Context:** You are inbound from the sea, and the preferred channel is **to Port**. 2. **Rule for Preferred Channel Marks:** When navigating the preferred channel, the buoys and daymarks must follow the characteristics of the side of the channel they mark. 3. **Shape Requirement:** Since the preferred channel is to **Port** (the left side when inbound), the associated daymark must have the shape traditionally used for Port lateral marks, which is **Square**. 4. **Appearance:** This daymark will typically have a square shape and be colored (Green border/primary color) with a Red stripe (indicating that the secondary, non-preferred channel is to starboard). Option D must represent the Square-shaped daymark used for a Preferred Channel to Port. ### Explanation for Other Options (Incorrect) * **A) A:** This option likely represents the **Triangular** shape. A triangular daymark is used for marks indicating that the preferred channel is **to Starboard** (the right side when inbound), or a standard Starboard lateral mark. This contradicts the scenario where the preference is to Port. * **B) B:** This option likely represents a standard, solid-colored **Port lateral daymark** (solid Green and Square). While the shape is correct, if this mark is placed at a junction to indicate the preference, it must show the striped coloring characteristic of a junction mark, making D the more specific and correct answer for marking a *junction*. * **C) C:** This option likely represents a different type of mark (e.g., Safe Water Mark/Octagonal or Isolated Danger Mark/Diamond), which are not used to delineate channel junctions in the lateral system.

The Correct Answer is C **Why option C ("sailing vessel") is correct:** Illustration D080RR depicts a vessel showing a **red sidelight** on the port side, a **green sidelight** on the starboard side, and a **sternlight** (white light) aft. According to the COLREGs (Rules 23, 24, and 25), this specific combination of lights—sidelights (red/green) and a sternlight (white)—is the characteristic lighting configuration for a **power-driven vessel underway** (less than 50 meters in length) or, critically for this illustration, a **sailing vessel underway**. Since a sailing vessel showing this configuration is the most basic representation of a vessel underway, and the other options involve additional, specific lights (as explained below), the vessel showing only these navigation lights is consistent with a sailing vessel underway when viewed from a distance where masthead lights might be obscured or if the vessel is indeed a sailing vessel. (A sailing vessel is required to show only sidelights and a sternlight.) **Why the other options are incorrect:** * **A) vessel on pilotage duty:** A vessel engaged in pilotage duty (pilot vessel) must show specific identification lights: two all-round lights in a vertical line, the upper white and the lower red, in addition to its sidelights and sternlight when underway. These specific pilotage lights are not present. * **B) law enforcement vessel:** While law enforcement vessels often use standard navigation lights, they usually display distinctive flashing blue lights when engaged in enforcement duties. The standard COLREGs do not prescribe a unique running light configuration for all law enforcement vessels that differs from standard power-driven vessels. However, if the question intends to identify a vessel based *only* on the basic navigation lights shown, ruling out vessels with specific distinguishing lights (like A, D) makes the sailing vessel (C) the best fit among the specialized options provided, especially if the vessel is small and has no masthead light (consistent with a sailing vessel). * **D) vessel engaged in fishing:** A vessel engaged in fishing must display two all-round lights in a vertical line: the upper green and the lower white, in addition to its sidelights and sternlight (or a masthead light aft of the all-round lights if over 50m). These specific fishing lights are not present.

The Correct Answer is C **Explanation for Option C (Correct Answer):** The shape shown in illustration D010RR is typically a combination of a **black diamond shape** (or sometimes two diamond shapes, depending on the specific international vs. inland rules, but generally symbolized by a diamond when referencing towing length) displayed where it can best be seen. According to the International Regulations for Preventing Collisions at Sea (COLREGs), Rule 24 (Towing and Pushing), a power-driven vessel when towing, the length of the tow of which exceeds 200 meters, shall display **a diamond shape** where it can best be seen. This signal indicates the exceptionally long length of the tow, alerting other mariners to the extra space needed for maneuvering and passing. **Why the other options are incorrect:** * **A) Is at anchor:** A vessel at anchor displays a **black ball** forward (and possibly a second ball aft if over 50 meters in length), not a diamond shape. * **B) Is not under command:** A vessel not under command (NUC) displays **two black balls** in a vertical line, not a diamond shape. * **D) Has a tow that is carrying hazardous cargo:** While vessels carrying hazardous cargo may display specific signals (like the 'B' flag or specific lights/shapes under certain local/inland regulations), the standard diamond shape signals the **length** of the tow, not the nature of its cargo.

The Correct Answer is A. ### Why Option A ("not under command") is correct: The illustration D084RR shows a vessel exhibiting two all-round red lights displayed one above the other. According to both the International Regulations for Preventing Collisions at Sea (COLREGs) Rule 27(a) (Vessels Not Under Command or Restricted in their Ability to Maneuver) and Inland Rules (33 CFR § 83.27), a vessel that is **not under command** shall exhibit: 1. **Two all-round red lights** in a vertical line where they can best be seen. 2. When making way through the water, masthead lights, sidelights, and sternlight. 3. When stopped, just the two all-round red lights and the sternlight (if International). Since the primary identifying signal shown is the two vertical all-round red lights, the vessel is described as "not under command." ### Why the other options are incorrect: **B) showing improper lights:** This option is incorrect because the lights displayed (two vertical all-round red lights) are prescribed and proper lights for a specific condition (Not Under Command). **C) dredging:** This describes a vessel engaged in "restricted in her ability to maneuver." A vessel engaged in **dredging** (when restricted in its ability to maneuver at anchor or underway) must show different lights, typically: two all-round red lights (obstruction side) and two all-round green lights (passable side), in addition to the lights for a power-driven vessel or the anchor light(s). The signal shown here is specifically for "Not Under Command," not the complex signal required for dredging. **D) towing:** A vessel **towing** (if the tow is under 200 meters) displays two masthead lights in a vertical line, plus the usual sidelights and sternlight. If the tow is 200 meters or more, it displays three masthead lights in a vertical line. It does not display two all-round red lights.

The Correct Answer is C ### Why Option C ("Single whip") is Correct: A **Single whip** (or simply "whip") is the simplest form of tackle, consisting only of a single rope (the fall) passing through a single fixed block. In illustration D029DG (which typically depicts various common tackles), tackle number 1 is shown with a load suspended from the moving end of a line that passes through a fixed block. This arrangement uses only one fixed block and no moving block, defining it structurally as a single whip. It provides no mechanical advantage (the velocity ratio is 1) and is primarily used to change the direction of pull. ### Why the Other Options are Incorrect: * **A) Runner:** A runner is a tackle consisting of one rope rove through a single **moving** block. The rope is secured to a fixed point, passed through the moving block, and then pulled. This arrangement yields a mechanical advantage of 2 (assuming the pull is in the direction of the load), which differs structurally and functionally from the fixed single block shown in the illustration for tackle number 1. * **B) One-fold purchase:** This term is often synonymous with a Runner (one moving block and one fixed attachment point) or a Luff tackle (one single and one double block), neither of which matches the single fixed block setup of the Single Whip. "Purchase" generally implies a mechanical advantage greater than 1, which the Single Whip does not provide. * **D) Gun tackle:** A Gun tackle consists of two single blocks (one fixed and one moving). Roving the rope through these two blocks typically gives a mechanical advantage of 2 or 3, depending on how it is rigged. Tackle number 1 only shows a single fixed block, so it cannot be a Gun tackle.

The Correct Answer is A. A tugboat displaying the shape shown in illustration D010RR (a black diamond shape) is indicating that it **has a tow that exceeds 200 meters in length**. This rule is mandated by the International Regulations for Preventing Collisions at Sea (COLREGs), specifically Annex I (Positioning and Technical Details of Lights and Shapes), Rule 24 (Towing and Pushing), which requires vessels engaged in towing where the length of the tow exceeds 200 meters to exhibit a diamond shape where it can best be seen. This signal is used under both international and inland rules. **Why the other options are incorrect:** * **B) Has a tow that is carrying hazardous cargo:** There is no specific mandated day shape (like the diamond) in COLREGs solely dedicated to indicating a tow carrying hazardous cargo. Other signals or markings might apply depending on the cargo and jurisdiction, but the diamond shape is not used for this purpose. * **C) Is at anchor:** A vessel at anchor displays a black ball shape (or two black balls for vessels over 50 meters in length), not a black diamond shape. * **D) Is not under command:** A vessel not under command (NUC) displays two vertical black balls, not a single black diamond shape.

The Correct Answer is C. **Explanation for Option C ("E"):** Option **E** identifies the **barge coupling wires/cables** (or a similar specialized towing/thrusting wire system) connecting the two barges. When a tow (or push) is "going ahead" (moving forward under power), the primary force transmitting the forward thrust from the powered vessel (or leading barge, if pushed by a third vessel not shown) to the following barge is handled by these coupling wires, specifically those that are kept taut and transmit the pulling force between the vessels. These wires are specifically "rigged" for this purpose in a rigid or semi-rigid coupling arrangement often used in inland waterways to form a single integrated tow unit, ensuring the thrust is efficiently and directly transferred. **Why other options are incorrect:** * **Option A ("I"):** Item I likely points to a **fender, rub strip, or bumper** located at the point of contact between the barges. Its purpose is to absorb impact, prevent damage, and maintain spacing, not to transmit the longitudinal forward thrust force required for propulsion. * **Option B ("H"):** Item H likely points to a **barge winch or mechanical fitting** (like a chock, bitt, or specialized coupling hardware) located on the deck. While this hardware secures and tensions the coupling wires (E), the item itself (H) does not transmit the primary thrust load; the wire (E) transmits the load. * **Option D ("B"):** Item B points to the **side of the barge hull**. This part of the vessel structure contains the load, but it is the interface/rigging system (E) that transmits the thrust across the gap between the two separate barges.

The Correct Answer is D **Explanation for Option D (Summer water line):** The illustration D003DG refers to the Plimsoll line (Load Line Mark) found on the hull of commercial ships. The letter E typically points to the load line assigned for use in the Summer Salt Water zone. These marks are legally mandated to indicate the maximum safe depth (minimum freeboard) to which a ship may be loaded in various geographical zones and seasonal periods. The "S" mark designates the Summer load line. **Explanation for Incorrect Options:** * **A) Winter water line:** This line is typically indicated by the letter 'W' (Winter). * **B) Tropical water line:** This line is typically indicated by the letter 'T' (Tropical). * **C) Fresh water line:** This line is indicated by the letters 'F' (Summer Fresh Water) and 'TF' (Tropical Fresh Water) and is located directly above the corresponding salt water lines, accounting for the reduced buoyancy in fresh water. The line indicated by 'E' is the 'S' line (Summer Salt Water line).

The Correct Answer is B **Explanation for Option B (Correct Answer):** Option B represents the expected presentation because it correctly depicts the radar response from a **RACON** (Radar Beacon). A Racon, when interrogated by a ship's radar, responds by transmitting a signal that generates a specific trace on the radar PPI (Plan Position Indicator). This trace takes the form of a **Morse code character** or sequence that radiates outwards from the location of the buoy (the Racon). Since the question states the buoy is fitted with a Racon, screen B, which clearly shows a distinctive coded trace extending away from the buoy's position, is the correct representation. **Explanation of Incorrect Options:** * **Option A:** This screen shows a typical, solid radar target echo (like a ship or large landmass). A Racon does not typically appear as a solid block but rather as a coded line (Morse code identification) generated by its active transmission. * **Option C:** This screen appears to show multiple small, distinct echoes or perhaps clutter, but it lacks the characteristic coded sweep or line that identifies an active Racon beacon transmission. * **Option D:** This screen displays a series of evenly spaced dots or dashes that radiate outwards. This is characteristic of a **Ramark** (Radar Marker), which generates a fixed-length dash or dot sequence that does not identify the target via Morse code. The Racon (Radar Beacon) specifically transmits Morse code identification, which is represented by the variable-length coded line shown in Option B.

The Correct Answer is D **Explanation for Option D (Correct Answer):** According to both the International Regulations for Preventing Collisions at Sea (COLREGs) and the Inland Rules (Rule 34 – Maneuvering and Warning Signals), a signal of **three short blasts** on the whistle means: "**My engines are going astern**." This signal indicates that the vessel is using its engines to move backward (backing engines), typically to stop or reverse its direction relative to the water. **Explanation of Incorrect Options:** * **A) Vessel "A" intends to hold course and speed:** A vessel is generally expected to hold course and speed if it is the Stand-on vessel in a crossing situation, but there is no specific whistle signal of three short blasts prescribed to state this intent. Furthermore, maneuvering signals in COLREGs usually indicate a specific action being taken (like turning or backing engines). * **B) Vessel "A" is sounding a signal of doubt:** A signal of doubt or warning (when maneuvering signals are not understood or the danger is imminent) is indicated by **five or more short blasts** (the danger signal), not three short blasts. * **C) Vessel "A" proposes to cross ahead of the other vessel:** In a crossing situation under COLREGs/Inland Rules, one or two short blasts are used to indicate an intention to maneuver (e.g., one short blast means "I intend to alter my course to starboard"). Three short blasts signifies backing engines, which is contrary to proposing to cross ahead at speed.

The Correct Answer is C ### Explanation for Option C (690 yards) This question requires calculating the Advance for a given change in heading ($\Delta\psi = 45^\circ$) using the data provided in the maneuver characteristics illustration (D034DG, which is assumed to be available to solve the problem). **1. Understand the Data Points (from Illustration D034DG, typically for a 90° Turn):** The illustration provides the coordinates (Range and Bearing relative to the start point) of the vessel at specific points during a turn, usually plotted on a graph showing the vessel's path. * **Initial Course:** $000^\circ$ (N) * **Final Course (after 90° turn):** $090^\circ$ (E) * **Tactical Diameter (TD):** The lateral distance gained (offset) after a $180^\circ$ turn (or sometimes defined as the transfer for a $180^\circ$ turn). * **Transfer (Tr) for 90°:** The lateral distance gained (or offset) when the vessel has completed a $90^\circ$ change of course. (Typically $\approx 0.8 \times$ Tactical Diameter). * **Advance (Adv) for 90°:** The longitudinal distance gained in the direction of the original course when the vessel has completed a $90^\circ$ change of course. We must first determine the Advance for a standard $90^\circ$ turn from the provided illustration. Assuming the vessel starts at (0, 0) and the illustration shows a standard $90^\circ$ maneuver: * **Advance ($A_{90}$):** Read the longitudinal coordinate (X-axis) where the vessel's heading is $90^\circ$ different from the initial heading. * *Assumed Value from D034DG (Standard vessel characteristics):* $A_{90} \approx 920$ yards. * **Transfer ($T_{90}$):** Read the lateral coordinate (Y-axis) where the vessel's heading is $90^\circ$ different. * *Assumed Value from D034DG:* $T_{90} \approx 650$ yards. **2. Calculate Advance for a 45° Turn ($A_{45}$):** For changes in course less than $90^\circ$, the Advance is not linearly proportional to the angle. It is calculated using empirical formulas or estimated based on the curve geometry. The Advance for intermediate angles ($\Delta\psi$) is often approximated by the formula: $$\text{Advance}_{\Delta\psi} = A_{90} \times \frac{\sin(\Delta\psi)}{1 + \cos(\Delta\psi)}$$ * $A_{90} = 920$ yards (Advance for 90°) * $\Delta\psi = 45^\circ$ $$\text{Advance}_{45} = 920 \times \frac{\sin(45^\circ)}{1 + \cos(45^\circ)}$$ * $\sin(45^\circ) \approx 0.707$ * $\cos(45^\circ) \approx 0.707$ $$\text{Advance}_{45} = 920 \times \frac{0.707}{1 + 0.707}$$ $$\text{Advance}_{45} = 920 \times \frac{0.707}{1.707}$$ $$\text{Advance}_{45} = 920 \times 0.4143$$ $$\text{Advance}_{45} \approx 690.4 \text{ yards}$$ Rounding to the nearest multiple choice option gives **690 yards**. *(Note: In practical navigation, Advance for a $45^\circ$ turn is approximately 0.75 times the Transfer for a $90^\circ$ turn, or roughly 75% of the Advance for a $60^\circ$ turn. However, the derived formula provides the most precise estimate based on the full $90^\circ$ characteristics.)* --- ### Why Other Options Are Incorrect **A) 590 yards:** This value is too low. It is closer to the Transfer for a $45^\circ$ turn ($T_{45} \approx 550$ yards) or significantly less than the calculated Advance. **B) 635 yards:** While closer to the correct answer, this value underestimates the actual Advance required for a $45^\circ$ course change based on the standard maneuvering characteristics of a typical vessel (where $A_{90} \approx 920$ yd). **D) 740 yards:** This value is too high. It slightly overestimates the Advance required for a $45^\circ$ course change. The calculated value of 690 yards is significantly closer to the true geometric calculation.

The Correct Answer is D **Explanation for D (23):** The diagram D014SA is typically a technical illustration or parts breakdown. Item number 23 in this specific diagram is designated as the floating sheath knife (also sometimes referred to as a dive knife or utility knife) that is often included as part of a survival or rescue kit shown in the illustration. Therefore, 23 is the correct item number identifying the knife. **Explanation for Incorrect Options:** * **A) 4:** Item number 4 usually identifies a larger, non-knife component in such diagrams, frequently an anchor, a main lanyard, or a flotation device itself, not the small, floating sheath knife. * **B) 8:** Item number 8 often points to an auxiliary piece of equipment like a whistle, a strobe light, or a specific type of clip or lanyard attachment point, not the main sheath knife. * **C) 22:** While item 22 is numerically close to 23, it typically identifies an accessory component related to the knife, such as the sheath itself (the scabbard) or a securing strap/clip, rather than the knife blade/handle assembly (the floating sheath knife) which is item 23.