Question and Answers

    marinetales April 15, 2021
    Great-circle distance is the shortest distance between any two points on the surface of a sphere that is measured along a path on the surface of the sphere. When calculating great-circle distance, the line of measurement does not pass through the sphere's interior. Great-circle distance is very important for trans oceanic voyages. One example of its usage is when long distance routes are drawn on flat maps (for instance, a Mercator projection). When drawn on flat maps, the routes often look curved. This is the routes lie on great circles. If the route was to be drawn as a straight (more)
    marinetales April 15, 2021
    for obtaining a single sight, long by chron method Can be used anytime during the daylight when both sun & horizon are visible. for obtaining a fix using long by Chron, more than one Celestial object shall be visible along with the horizon. This is only achievable at dusk or dawn.
    marinetales April 21, 2021
    Following factors are taken into account while choosing an anchor position - 1. Distance off from other vessels 2. Distance off from nearest danger 3. Nature of holding ground 4. Own vessel size 5. Duration of stay at Anchorage 6. Weather forecast 7. In Case own vessel has to undergo repairs at anchorage ( immobilisation) 8. Presence of underwater obstructions 9. Any other factor which affects the safety of vessel directly or indirectly
    marinetales October 27, 2020
    Each position circle found using the Sextant Altitude is of immense radius. Therefore, any short length of the arc of some circle can be considered as an straight line . Comparing the observed distance to the celestial body the calculated distance using an estimated position provides the distance towards, or away from the body.. The observed distance is known as the True Zenith Distance (TZD.) The value based on the assumed position is the Calculated Zenith Distance (CZD.) The difference between the two is known as the Intercept. The closest point on this circle is known as the Intercept Terminal (more)
    marinetales September 9, 2020
    The best and perhaps the only way to reduce the squat is to reduce the vessel’s speed.
    marinetales August 28, 2020
    The Tidal Diamonds are the symbols marked usually on British Admiralty Charts that indicates the direction and speed of the Tidal Streams at particular location. The Tidal streams are given in the form of the table and tidal diamonds are marked in the first row. The Tidal diamonds are marked by purple color rhombus and contains Alphabetical letter starting from A, B, C and so on... The Tidal diamonds accompanies the position (mentioned in Latitude and Longitude) next to it and refers to the position on the chart on which the calculated tidal stream is expected.
    marinetales August 22, 2020
    Rule 13 (Overtaking) ALWAYS supersedes Rule 18 (Responsibility between Vessels). So, in this case it is the Responsibility of the Overtaking vessel (NUC Vessel) in this case to keep clear of you. Own vessel has to give ”wake up signal” of five short blasts on the ship’s whistle. If no action is taken by other vessel, give wide alteration to Port and take a round turn after passing by the stern of the NUC vessel.
    marinetales August 23, 2020
    Steady order is usually given when the vessel is required to be steered on a certain course as ordered by the Master. (Eg Steady on Course 180 deg) Steady as she goes order is given when the vessel is required to keep on the course that she is steering CURRENTLY.
    marinetales August 23, 2020
    Following are the ways – 1. Electronic Position Fixing methods such as GPS 2. Radar Fix 3. Visual Bearing Fixes 4. Celestial Fixes (such as Long by Chron, Mer Pass, Polaris etc) 5. Horizontal Sextant Angles 6. Vertical Sextant Angles 7. Running Fix 8. Three point bearing
    marinetales August 30, 2020
    Cardinal Buoys are used to indicate the position of the hazard and direction of the safe water to which the vessel should pass. Cardinal buoys by their top marks indicate the direction of safety as a cardinal (compass) direction (north, east, south or west) relative to the mark. The presence of top mark helps the navigator in easily identifying the type of Cardinal Buoy and the direction of the safe water where the vessel must proceed. The "Top-marks" being clearly visible reduces the chances of error.
    marinetales August 24, 2020
    Not necessarily one will be able to identify AGROUND vessel, alone, by looking from astern. It is because there is a high possibility of mistaking it with vessel NUC making way. So, we have to look at other signs too. Most accurate way of determining the vessel is whether the vessel is having ground speed or not. Aground vessel will be having ground speed "zero" compared to NUC making way having certain amount of speed.
    marinetales August 23, 2020
    Collision happens when there is an structural impact between a vessel and another vessel (or FLOATING Object) Allision is the structural impact between a vessel and a FIXED object such as Bridge or Fender etc.
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