Question 70 ONC03 - Master LT 500-1600 GRT

The Correct Answer is C ### Why Option C (Relative bearings) is Correct: In the merchant service (and generally in maritime navigation), a look-out reports sightings using **relative bearings**. A relative bearing is the angle measured clockwise from the ship's own heading (the bow, or $000^{\circ}$ Relative) to the object. This method is preferred for several reasons: 1. **Immediacy and Consistency:** It provides an immediate and consistent way to pinpoint the location of the contact relative to the vessel, regardless of the ship's actual course (True or Magnetic). 2. **Standardization:** It is the standard procedure taught to look-outs globally, ensuring unambiguous communication between the look-out and the Officer of the Watch (OOW). 3. **Collision Avoidance:** Reporting 'Dead Ahead' ($000^{\circ}$ R) or 'Broad on the Starboard Bow' ($045^{\circ}$ R) instantly alerts the OOW to the contact's position relative to the closest point of approach. *** ### Why Other Options Are Incorrect: **A) Magnetic bearings:** Magnetic bearings require the look-out to use a compass repeater (like an azimuth circle) and then apply deviation/variation corrections. This is a navigation task, not a look-out reporting task. The look-out's primary function is immediate, visual reporting, not complex compass measurement. **B) True bearings:** True bearings require measuring the angle clockwise from True North to the object. Like magnetic bearings, this requires using specialized equipment and involves calculations (applying variation/deviation and ship's head). This procedure is typically done by the OOW or navigator after receiving the relative bearing report, not by the look-out initially. **D) Gyro bearings:** Gyro bearings are measured using the ship's gyrocompass, indicating the angle from Gyro North. While sometimes used in navigation, this still requires specific measuring tools (azimuth circle/repeater) and is not the standardized initial reporting method for a look-out. The look-out reports where the object is *relative to the ship*, not relative to a fixed geographic direction.