Question and Answers

    Question
    marinetales May 22, 2021
    Following are the duties of lookout on bridge: 1. Reporting any vessel target followed by the bearing of the target vessel by sight 2. Reporting the aspect of the target vessel 3. Reporting and sound signal and approximate bearing by hearing 4. Looking out for any floating debris, objects and navigational hazards 5. Looking out and reporting for any unidentified objects
    marinetales August 23, 2020
    A compass (when used for steering) is required to be damped so that the needle does not shakes rapidly and it is easier for the navigator to read off the compass. Therefore, In order to damp the compass a liquid is required to be filled up in compass bowl. This type of compass is called wet card compass. Now, this liquid is required to have the following properties - 1. Should not get evaporated in warm climates 2. Should not get frozen in cold climates 3. Should have Small coefficient of expansion 4. Should be clear 5. Should not discolor/damage the compass card 6. Low Specific gravity 7. Easily available How to achieve this ? This is achieved by the creating a mixture of distilled water and Ethyl Alcohol in the ratio of 2:1 respectively. In warm climate, the distilled water prevents the mixture from evaporating (as the mixture is having higher ratio of distilled water) In cold climate, the ethyl alcohol will prevent the mixture from freezing. The mixture has low coefficient of expansion (as mainly water is there) and the mixture is clear. Ethyl alcohol is easily available on ship.
    marinetales May 20, 2021
    Following shall be carried out for the maintenance of SCBA: Visual Checks - 1. Check Face Mask for scratches 2. Check Rubber components (face seal and tubing) for cracks etc 3. Check straps for tightness and fraying 4. Check condition of cylinder 5. Check the condition of belts 6. Check condition of tubings and gauges Operational Checks - 1. Check bottle pressure by opening the valve and closing the demand valve 2. meanwhile, check for air seal in the face mask 3. Release the pressure and try operation of low level whistle/alarm 4. Turn off the bottle valve
    marinetales August 23, 2020
    When a ship is maneuvering in/near extremely shallow waters such as near a shoal she is likely to take a sudden sheer (sheer means quickly changing of course), first towards the shoal/shallow patch and then violently away. This is called smelling the ground.
    marinetales May 19, 2021
    Following factors can effect the turning circle of the vessel: 1. Currents 2. Wind 3. Sea state 4. Condition - loaded, partially loaded or ballast 5. Speed of the vessel 6. UKC
    marinetales May 20, 2021
    Contents of Wheel house poster also called Maneuvering Booklet : 1. Name of Ship, Call Sign, Gross tonnage and Net tonnage, Displacement, Deadweight and Block Coefficient (at Summer load draft) 2. Forward and Aft draft at which the Maneuvering data was obtained (Loaded and Ballast) 3. Steering particulars - Type of Rudder, Max Rudder Angle, Time hard over to hard over (with one power unit and both power unit), Minimum speed required to maintain course, Rudder angle for the neutral effect 4. Anchor chains on both port and starboard anchor and maximum rate for heaving the anchor 5. Propulsion particulars - type of engine, type of propeller 6. Engine order (dead slow, slow, full etc), their corresponding RPM Values and corresponding Speed obtained in both loaded and ballast. 7. Details of Bow and Stern thruster 8. Man overboard recovery turn and rescue maneuver details 9. Turning circle data at Max rudder angles (in loaded and ballast) 10. Track reach details in loaded and ballast 11. Stopping characteristics 12. IMO Visibility Criteria Attach find a sample of wheelhouse poster 3.
    marinetales August 23, 2020
    Following techniques will help you to determine the position using a lighthouse – 1. Taking a Radar Fix (if the Lighthouse is fitted with RACON or is Radar Conspicuous Object) 2. Visual Bearing 3. Vertical Sextant Angle 4. Running Fix 5. Three Point Bearing
    marinetales May 22, 2021
    Admiralty Hydrographic Notes allow you to inform the Admiralty of any navigationally significant information. This information could include new or suspected dangers, changes to navigational aids, amendments to details included in publications and suspicious charts or publications that could be counterfeit. This information can be submitted in format prescribed by the Admiralty office.
    marinetales May 20, 2021
    A sector on the radar Screen in which the appearance of radar echoes is improbable because of an obstruction near the antenna. It is different from the Blind Sector. While both blind and shadow sectors have the same basic cause, blind sectors generally occur at the larger angles subtended by the obstruction.
    marinetales May 20, 2021
    The scale of a nautical chart is a way to convert inches on paper to inches in the real world. Chart scales are expressed as ratios (1:100,000 for example), so the unit of measure does not matter. On a chart whose scale is 1:100,000, one inch on paper represents 100,000 inches in the real world.
    marinetales May 22, 2021
    Category Zone of Confidence (CATZOC) values are used to indicate the accuracy of data presented on charts to assist mariners with determining a safe Under Keel Clearance (UKC). Category Zone of Confidence (CATZOC) values are assigned to geographical areas to indicate whether data meets a minimum set of criteria for position, depth accuracy and seafloor coverage. The Zone of Confidence (ZOC) value is dependent on the positional and depth accuracy of the survey. By understanding the accuracy limitations of the underlying data in greater detail, the mariner can manage the level of risk when navigating in a particular area.​ ECDIS display these CATZOC values in ENCs using a triangular or lozenge shaped symbol pattern. The number of stars contained within these symbols denotes the CATZOC value. For example six stars are given to the highest level of data quality (A1) and two stars to the lowest (D). A single star is not used to avoid possible confusion with a rock symbol. Areas that have not been assessed for CATZOC are shown as the symbol (U) for unassessed.
    marinetales May 20, 2021
    Barometric tendency is the amount of atmospheric pressure change during a specified period of time, often a three-hour period preceding an observation. Barometric tendency is composed of two parts, the pressure change and the pressure characteristic. The pressure change is the net difference between pressure readings at the beginning and ending of a specified interval of time. The pressure characteristic is an indication of how the pressure has been changing during that specified period of time, for example, decreasing then increasing, or increasing and then increasing more rapidly. Barometric tendency is most accurately measured by a barograph (pic attached).
    marinetales May 24, 2021
    Both parallel track and creeping line search are based on covering (sweeping) the search area by maintaining parallel tracks as shown in Fig below. The only difference between these two is in the orientation of the search legs, i.e. if the search legs are parallel to the long sides (major axis) or short sides (minor axis) of the designated search area.
    marinetales May 22, 2021
    A tidal bore, often simply given as bore in context, is a tidal phenomenon in which the leading edge of the incoming tide forms a wave (or waves) of water that travels up a river or narrow bay against the direction of the river or bay's current. Bores occur in relatively few locations worldwide, usually in areas with a large tidal range (typically more than 6 meters (20 ft) between high and low tide) and where incoming tides are funneled into a shallow, narrowing river or lake via a broad bay. The funnel-like shape not only increases the tidal range, but it can also decrease the duration of the flood tide, down to a point where the flood appears as a sudden increase in the water level. A tidal bore takes place during the flood tide and never during the ebb tide. See the attached picture.
    marinetales June 17, 2021
    As per the COLREG, A vessel constrained by her draught is a power-driven vessel which, because of her draught in relation to the available depth and width of the navigable water, is severely restricted in her ability to deviate from the course she is following, What is important to note here is that the definition focuses not only on the available depth BUT ALSO the width of the navigable water. Assuming that the width of Traffic lane is not sufficient enough and surrounding areas are having shallow depths - will render the vessel to be severely restricted in her ability to deviate from the course. In this situation, the vessel shall in consultation with the VTS can display the lights that are displayed by the vessel constrained by her draught.
    marinetales May 22, 2021
    Great Circle distance is a shorter distance because it follows the distance between two points lying on the great circle (which is the shortest distance on the surface of the earth). This happens because the earth is spherical in shape and any shortest distance between two points should be lying on a great circle, the plane of which should be passing through the centre of the earth.
    marinetales May 22, 2021
    Following information can be obtained from Routeing Charts - 1. Location of Major Seaports 2. Distance between the Major Seaports 3. Wind patterns and Wind Roses 4. Current patterns 5. Sea Ice limits 6. Loadline limits 7. Mean Air temperature and Mean sea temperature
    marinetales May 22, 2021
    There are many ways you can confirm that the anchor is dragging. Following are some of them - 1. Constant Change in bearings from a fixed object (preferably objects abeam) 2. Constant Change in vessel's position 3. Vessel moving out of the turning circle 4. Anchor chain vibrating constantly 5. Change in cable stay (long to short to long and short again) 6. If the past position of the vessel (as ECDIS / Course recorder) is subscribing a Figure of Eight
    marinetales May 24, 2021
    A lighthouse has the following characteristics - 1. Name / Number of the lighthouse 2. Position / location 3. List characteristics - flashing / color of light / duration (Isophase, ocuulting etc) 4. Construction description (Eg white round tower, red bands etc) 5. Range of light (Geographical) 6. Whether operational or not
    marinetales May 24, 2021
    Rule 19 applies to any situation when the vessels are navigating in or near areas of restricted visibility and are not in sight of one another.
    marinetales May 22, 2021
    The term "vessel constrained by her draught" means a power-driven vessel which because of her draught in relation to the available depth of water is severely restricted in here ability to deviate from the course she is following. As per the definition the CBD vessel is having an exceptional draft and in order to mobilize the vessel of such draft, the vessel needs to be power driven. Also, as per the Rule No 18 Responsibilities between vessels, the CBD vessel in certain circumstances have to be give - way vessel. In this situation, the CBD vessel has to take timely and effective action which can only be taken if the vessel is power driven.
    marinetales May 17, 2021
    Short round turn is to be executed as follows ( assuming Right Hand Propeller) provided that vessel is not experiencing very strong current/wind, other wise the turn will not be executed that effectively. 1. Dead slow ahead on the engines, wheel hard to starboard 2. The moment the vessel starts to turn, stop the engines 3. Dead slow stern on the engines, wheel midships 4. Due to transverse thrust, the vessel will continue turning to starboard 5. Repeat the step no 1 and let the vessel turn and finally steady on the course you desire