Question and Answers

    Question
    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
    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 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
    marinetales May 19, 2021
    Good time means ‘early’. There is no specific time at which good time begins. It’ll depend on a particular situation. Manoeuvres taken to avoid a close-quarters situation should be taken at a time when the responsible officer does not have to make a quick decision or a decision based on inadequate information. We can say that if a vessel fails to take action in good time, she may find herself in a close-quarters situation. This paragraph does not say that action is to be taken in good time to avoid a collision.
    marinetales May 17, 2021
    No, the effectiveness of the rudder depends upon the rate of water flowing past it. During drifting since no such water flow is there, the effect of the Rudder becomes Null.
    marinetales May 14, 2021
    The Schedule A of the NP133C shows which ENC's are licensed for use by the vessel and which base CD's or DVD Volumes are required to install them.
    marinetales May 14, 2021
    Stopping distance is the distance covered by a ship (which is making headway), after the engines are stopped. Stopping distance are of two types : 1. Inertia Stop 2. Crash Stop 1. Inertia Stop: when the engine of the ship is stopped, the ship will continue moving in the same direction for some more distance due to inertia. Here no astern command is given (used to produce “braking effect” for ships), and hence ship will travel more distance in the inertia stop method. 2. Crash Stop: Here the engine, which is moving in an ahead direction is given an order for full astern, leaving the rudder in the mid ship position to stop the ship within minimum distance and shortest possible time.
    marinetales August 23, 2020
    In accordance with Rule No 18, both RAM and NUC vessels have the responsibility to keep clear of each other. In this case, both vessel should take action and such action should preferably be to starboard.