MODU01 - Offshore Installation Manager

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), specifically Rule 13 (Overtaking) and Rule 17 (Action by Stand-on Vessel). 1. **Rule 13 (Overtaking):** Establishes that the vessel being overtaken (Vessel B) is the **stand-on vessel** and the vessel overtaking (Vessel A) is the **give-way vessel**. Vessel A is required to keep clear of Vessel B. 2. **Rule 17 (Action by Stand-on Vessel):** Generally requires the stand-on vessel to **keep her course and speed** while the give-way vessel executes the necessary maneuvers to pass safely. This predictability is crucial for collision avoidance. Therefore, Vessel B (the stand-on vessel) is required to maintain its course and speed. --- **Explanation for Incorrect Options:** * **A) should slow down until vessel "A" has passed:** This is incorrect. Changing speed (slowing down) would violate Rule 17, making the intentions of Vessel B unpredictable and potentially complicating Vessel A's safe 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 obligated by Rule 17 to maintain a predictable course and speed. Varying courses would be highly dangerous and violate the fundamental principle of the stand-on/give-way relationship. * **D) should change course to the right:** This is incorrect. Changing course would violate Rule 17. The stand-on vessel should only maneuver if collision cannot be avoided by the action of the give-way vessel alone (Rule 17(a)(ii) and (b)), which is not implied in a standard overtaking situation. Furthermore, arbitrarily changing course adds unpredictability.

The Correct Answer is D. **Explanation for Option D (Correct):** Option D, "not impede the passage of vessel 'B'", is the correct action because Vessel "A" (engaged in fishing) is operating in a narrow channel. Rule 9(b) of the COLREGs (both International and Inland) explicitly 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. Furthermore, Rule 18(d)(i) states that vessels engaged in fishing shall not impede the passage of any other vessel navigating within a narrow channel or fairway. Vessel "B" is a tanker, a large vessel likely restricted to the channel. When Vessel "B" sounds five short and rapid blasts, it is indicating danger or doubt that the proposed action (likely B's intent to proceed) is safe, likely due to Vessel A's presence. In this scenario, Vessel "A" has the duty to avoid impeding the safe passage of the larger, channel-restricted vessel. **Explanation for Other Options (Incorrect):** * **A) maintain course and speed:** This is incorrect. Vessel "B's" five short blasts indicate immediate danger or doubt, demanding that Vessel "A" take immediate evasive action, which means changing course or speed to ensure Vessel "B" can proceed safely. Maintaining course and speed would violate Vessel A's duty not to impede traffic in a narrow channel and ignore the danger signal. * **B) not answer the whistle signals from vessel "B":** This is incorrect. While the five-blast signal is a danger signal (not an operating signal requiring an immediate response like "I agree" or "I disagree"), Vessel "A" must acknowledge the situation by taking immediate action (Rule 2, Good Seamanship) and ensure the safe passage of Vessel "B" (Rule 9). Ignoring the signal and taking no action is unsafe and irresponsible. * **C) sound one prolonged followed by two short blasts:** This signal indicates a vessel is preparing to overtake on the port side in a narrow channel (Inland Rules) or a towing signal (International Rules, not applicable here). It is not the appropriate response to a danger signal, nor does it fulfill Vessel A's duty to clear the channel. Vessel "A" must take action to move out of the way, not propose an overtaking maneuver.

The Correct Answer is C ### Explanation for Option C (special flashing light) **The special flashing light is correct because it is a mandatory, identifying light displayed forward on power-driven vessels engaged in a common Inland River operation.** 1. **Inland Rules Mandate:** Under the Inland Navigation Rules (Rule 23(e)), a power-driven vessel pushing ahead or towing alongside on the Western Rivers (or waters specified by the Commandant) must display a **special flashing light**. 2. **Visibility and Purpose:** This light is amber, flashes 50–70 times per minute, and is placed forward. It is visible over a horizontal arc of 180–225 degrees, centered on the centerline, meaning it is specifically designed to be seen by vessels approaching head-on or slightly off the bow. 3. **Conclusion for Scenario:** Since the vessels are "INLAND ONLY" and meeting on a river, Vessel B is likely a towing vessel pushing a tow. If Vessel B is pushing, this special flashing light is displayed at the bow and would be clearly visible to Vessel A during the meeting situation. *** ### Explanation for Incorrect Options **A) yellow towing light** The yellow towing light (required under Rule 24 for towing astern) is a white or yellow light positioned vertically above the stern light and is visible only in the **stern sector (135 degrees astern)**. Since Vessel A and Vessel B are meeting, Vessel A is looking at Vessel B's bow. Therefore, Vessel A would not see the towing light. **B) red sidelight** While a red sidelight (port side) *may* be seen depending on the final angle of the passing maneuver, it is not a definite identifying light for a vessel meeting head-on (in which case, masthead lights and the special flashing light are primary). More importantly, the sighting of the sidelight depends entirely on A being slightly off B's port bow. The special flashing light (C) is mandatory for the operation and displayed in the forward sector, making it the definitive unique light visible during a meeting in this specific inland context. **D) All of the above** This option is incorrect because the yellow towing light (A) is not visible in a meeting situation.

The Correct Answer is C ### Why Option C ("sailing vessel") is Correct The light configuration described by standard navigation rules (Rule 25) for a vessel that is operating under sail—displaying only the standard **Red sidelight** (port), **Green sidelight** (starboard), and a **White sternlight**—is definitive proof that the vessel is a **sailing vessel**. Crucially, a sailing vessel does *not* display the white masthead (steaming) light required for a power-driven vessel. If the illustration shows only these three basic navigational lights (or a single combined lantern displaying them), the vessel is operating under sail. ### Why Other Options Are Incorrect **A) vessel on pilotage duty:** A vessel engaged in pilotage duty must display the mandatory identification lights of a **white light over a red light (W/R)** at the masthead, in addition to its standard navigation lights (sidelights and sternlight). The vessel in the illustration is missing the specific W/R identification lights. **B) law enforcement vessel:** Law enforcement vessels typically use standard navigation lights, or may employ specialized warning lights (such as blue flashing lights in Inland waters) when engaged in official duties. Their standard display does not uniquely consist only of sidelights and a sternlight. **D) vessel engaged in fishing:** A vessel engaged in fishing (other than trawling) must display the mandatory all-around identification lights of a **green light over a white light (G/W)**, in addition to its standard navigation lights when making way. The configuration for a sailing vessel is missing the essential G/W fishing lights.

The Correct Answer is C **Explanation for Option C (Correct):** The illustration D010RR depicts the required daytime shapes prescribed under the International Regulations for Preventing Collisions at Sea (COLREGs) Rule 24 (Towing and Pushing). Specifically, it shows a vessel displaying a **diamond shape**. COLREGs Rule 24(a)(i) requires 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, to exhibit a **diamond shape** where it can best be seen. Therefore, a vessel displaying this shape has a tow that exceeds 200 meters in length. **Explanation of Incorrect Options:** **A) Is at anchor:** A vessel at anchor displays a **ball** shape forward (COLREGs Rule 30). **B) Is not under command:** A vessel not under command displays **two balls** in a vertical line (COLREGs Rule 27(a)). **D) Has a tow that is carrying hazardous cargo:** There is no specific shape required by COLREGs solely for a tow carrying hazardous cargo, although additional shapes (like a cylinder) might be required if the vessel is restricted in its ability to maneuver due to the nature of the operation (e.g., dredging, mine clearance). However, the diamond shape specifically signifies the length of the tow, not the nature of its cargo.

The Correct Answer is A. ### Explanation for Option A (Correct Answer) Option A, **not under command (NUC)**, is correct because the illustration D084RR (which depicts the lights visible from the bow/front) shows two all-around red lights displayed vertically where the masthead light(s) would typically be, and also shows sidelights (red on the port side, green on the starboard side). According to both the International Regulations for Preventing Collision at Sea (COLREGS Rule 27(a)) and Inland Rules: * A vessel **not under command** shall exhibit **two all-around red lights in a vertical line** where they can best be seen. * If making way through the water (as suggested by the presence of sidelights), it must also display sidelights and a stern light (though the stern light is not visible from the bow view). The arrangement of two all-around red lights, indicating operational disability, combined with sidelights, confirms the vessel is underway but unable to maneuver as required by the rules (NUC). ### Explanation for Incorrect Options **B) showing improper lights:** While this vessel is exhibiting specific lights that indicate its status, the configuration shown (two all-around red lights + sidelights) is the **proper and mandated signal** for a vessel NUC making way. Therefore, the lights are not improper; they are correct for the defined situation. **C) dredging:** A vessel engaged in **dredging** (or underwater operations) is restricted in its ability to maneuver. A vessel restricted in its ability to maneuver (RAM) typically exhibits three all-around lights in a vertical line: Red-White-Red. It would also display a masthead light, sidelights, and stern light if underway. If the vessel is also obstructing a channel, it displays two all-around red lights on the side of the obstruction and two all-around green lights on the side safe for passage. The display of only two all-around red lights is insufficient and incorrect for the primary RAM signal (R-W-R) or the obstruction signal. **D) towing:** A vessel engaged in **towing** (where the length of the tow is less than 200 meters) exhibits two masthead lights in a vertical line, plus sidelights and a stern light. If the tow length exceeds 200 meters, three masthead lights are shown vertically. The two all-around red lights shown in the illustration are the primary characteristic of NUC, not towing.

The Correct Answer is A. A tugboat displaying the shape shown in illustration D010RR – which is an **all-around white diamond shape** – is indicating that it has a tow that **exceeds 200 meters in length**. This signal is mandated by both the International Regulations for Preventing Collisions at Sea (COLREGs, Rule 24(a)(ii)) and Inland Navigation Rules for a power-driven vessel when towing, provided the length of the tow measured from the stern of the towing vessel to the after end of the tow exceeds 200 meters. This shape must be exhibited where it can best be seen. **Why other options are incorrect:** * **B) Has a tow that is carrying hazardous cargo:** While vessels carrying dangerous goods must comply with specific rules and might display other signals (like the 'B' flag or lights/shapes related to restricted maneuverability if applicable), the white diamond shape is exclusively associated with the length of the tow, not the nature of the cargo. * **C) Is at anchor:** A vessel at anchor displays specific day shapes: a black ball or, if less than 50 meters, none might be required (Inland). A vessel over 100 meters must use a cylinder (or similar structure) instead of a ball forward. The diamond shape is never used to indicate anchoring. * **D) Is not under command:** A vessel not under command (NUC) displays two vertical black balls. The diamond shape is only used to indicate the length of the tow.

The Correct Answer is D 1. **Explanation for Option D (Correct):** The signal of three short blasts (short blast defined as about one second in duration) sounded by a power-driven vessel is defined by Rule 34(a) of both the International Regulations for Preventing Collisions at Sea (COLREGs) and the Inland Rules. This specific maneuvering signal means, "I am operating astern propulsion" (backing engines). Therefore, Vessel "A" is informing the other vessel that it is backing its engines. 2. **Explanation for Other Options (Incorrect):** * **A) Vessel "A" intends to hold course and speed:** This intention is typically implied when a vessel is the stand-on vessel, but there is no specific whistle signal for merely holding course and speed. A single short blast means "I am altering my course to starboard," and two short blasts means "I am altering my course to port." Three short blasts specifically indicates astern propulsion, not holding course and speed. * **B) Vessel "A" is sounding a signal of doubt:** A signal of doubt, or the danger signal, consists of at least five short blasts. Three short blasts is a specific maneuvering signal, not the danger signal. * **C) Vessel "A" proposes to cross ahead of the other vessel:** A proposal to cross ahead (a meaning often associated with overtaking situations under Inland Rules, or a proposal in narrow channels) would generally involve a single short blast (if altering course to starboard) or two short blasts (if altering course to port), or specific passing signals (like one prolonged, one short, one prolonged, one short for overtaking under Inland Rules). Three short blasts exclusively means the vessel is backing its engines.