Question and Answers

    Question
    marinetales May 13, 2021
    The Environment Protection Agency (EPA) of the USA issued its most recent Vessels General Permit, under the National Pollutant Discharge Elimination System (NPDES), a Clean Water Act (CWA) program, in 2013. The permit applies to large commercial vessels (79 feet (24 m) in length or greater) (except fishing vessels) and regulates 26 specific types of vessel discharges: Deck Washdown and Runoff and Above Water Line Hull Cleaning Bilge water/Oily Water Separator Effluent Ballast water Anti-fouling Hull Coatings/Hull Coating Leachate Aqueous film forming foam (AFFF) Boiler/Economizer Blowdown Cathodic protection Chain Locker Effluent Controllable Pitch Propeller and Thruster Hydraulic Fluid and other (more)
    marinetales May 13, 2021
    Container ships are highly subjected to torsional moments because of their very large hatch openings. This leads to even higher warping stresses at the corners of the openings due to lack of torsional rigidity. The upper part of the double hull in such ships is fitted with torsion box. Torsion boxes are fitted with welded joints on the side shell as on the deck plating which prevent the torsion produced by twisting.
    marinetales May 13, 2021
    Refrigerant 22 is now probably the most common refrigerant used on ships. It provides a considerable range of low-temperature operation.
    marinetales May 13, 2021
    Following are the reasons: 1. Bunker oil is refined oil and not crude oil. 2. Bunker fuel is required to have a Flash point temperature of 60 deg C and above as per the Classification Society rules. 3. Bunker fuel is not flammable under normal temperature and pressure, as carried in the bunker tanks of ships. Provided the bunker tanks are not heated above around 40C, they are not considered flammable 4. Further, owing to the smaller size of the bunker tanks, the atmosphere usually is "too rich" to cause combustion
    marinetales May 9, 2021
    There are two stabilisation modes on Radar – ground and sea. Ground stabilisation means that the display is referenced to the seabed by GNSS or through a twin-axis Doppler log. For sea stabilisation the display is referenced to the sea current that own ship is experiencing, typically based on SDME measurements. It is generally accepted that the ground stabilised mode is more useful for normal navigation, especially when combined with setting tracked targets to show their True vectors. However, since set and drift affect heading and aspect, ground stabilised displays should be used with caution where target tracking is concerned. (more)
    marinetales May 9, 2021
    As per the latest changes in MARPOL The bunker delivery note shall include a declaration signed and certified by the fuel oil supplier's representative that the fuel oil supplied is in conformity with regulation 18.3 of MARPOL Annex VI and that the sulphur content of the fuel oil supplied does not exceed the Sulphur limits. Additionally, the fuel oil samples are always lab tested for suitability and compliance prior being used as per the management instructions.
    marinetales May 9, 2021
    Following certificates and documentation is required: 1. DMLC PART 1 2. DMLC PART 2 3. Maritime Labour Certificate 4. Latest inspection report by the MLC inspector 5. Copy of CBA ( for both officers & crew) 6. Seafarer Employment Agreements 7. Medical Certificates of crew 8. Various licences and endorsements of the crew 9. Watch keeping documents and CoC for Chief cook 10. Records of training and familiarisation 11. Onboard complaint procedures
    Category: Ship Stability
    marinetales May 9, 2021
    When an unstable vessel heels over towards a progressively increasing angle of heel, at a certain angle of heel, the centre of buoyancy (B) may fall vertically below the centre of gravity (G). When this occurs, the vessel goes to neutral equilibrium, and the angle of heel at which it happens is called angle of loll. Although a vessel at angle of loll does display features of stable equilibrium, this is a dangerous situation and rapid remedial action is required to prevent the vessel from capsizing. Angle off loll is often caused by the influence of a large free surface (more)
    marinetales May 9, 2021
    Following are the errors that can be encountered in Echo Sounder: 1. Stylus speed error: The stylus is rotating with a certain constant speed and the speed of the stylus that the time is taken for the stylus to travel from top to bottom is exactly equal to that for an acoustic pulse to travel twice the distance of the range selected. Due to the fluctuation in the voltage, the speed of the stylus motor changes hence the depth recorded Will be inaccurate. It should be checked periodically and adjusted as per the instruction is given in the manual. 2. (more)
    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 April 15, 2021
    any discharge into the sea of oil or oily mixtures from ships shall be prohibited. A Discharges outside special areas 2 Any discharge into the sea of oil or oily mixtures from ships of 400 gross tonnage and above shall be prohibited except when all the following conditions are satisfied: .1 the ship is proceeding en route; .2 the oily mixture is processed through an oil filtering equipment meeting the requirements of regulation 14 of this Annex; .3 the oil content of the effluent without dilution does not exceed 15 parts per million; .4 the oily mixture does not originate (more)
    Category: Meteorology
    marinetales April 15, 2021
    For differentiating between dew and mist letus first understand fog. Fog can be described as a cloud forming very close to or at ground level. It requires air with sufficient moisture to cool or to be cooled to a temperature to achieve condensation. Once condensation occurs, visibility decreases dramatically. It therefore becomes very hazardous. Fog does not necessarily have to be uniform, or widespread. Some areas may have thick fog whilst others may miss out completely. Fog is more common in valleys and near creeks or streams. It also most commonly occurs overnight and during the morning. However, in colder (more)
    Category: Cargo Work
    marinetales April 15, 2021
    Standardised Cargo : Standardised Cargo means a Cargo for Which a ship is provided with an approved securing system based upon Cargo units of specific types. Non -standardised Cargo : means Cargo which requires individual stowage and securing arrangements.
    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.
    Category: Cargo Work
    marinetales April 15, 2021
    Standardised Cargo : Standardised Cargo means a Cargo for Which a ship is provided with an approved securing system based upon Cargo units of specific types. Non -standardised Cargo : means Cargo which requires individual stowage and securing arrangements.
    Category: Cargo Work
    marinetales April 15, 2021
    At least 16% of Oxygen is required to support combustion.
    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)
    Category: Emergencies
    marinetales April 7, 2021
    Radio medical advice is available free of charge to provide support in cases where an individual suffers either illness or an accident at sea. The advice is intended to supplement the first aid training of the vessel’s crew and the written guidance available, for example in the Ship Captain’s Medical Guide. To obtain radio medical advice the master should first contact the nearest coast radio station or CIRM Italy. Contact should first be made using VHF, MF, HF DSC or Inmarsat Upon receiving the instructions from the doctor the evacuation shall be arranged. In such a case Master might need (more)
    Category: Cargo Work
    marinetales April 6, 2021
    Mixing fully refrigerated Butane with fully refrigerated Propane generates flash gas, and there is a risk that if the mixing is conducted too fast and/or the pressure tendency is not being monitored scrupulously enough, the ship’s cargo tank relief valves will lift – causing a hazardous, uncontrolled release of a LPG vapour cloud on the jetty and around the vessel. This is most likely to occur during the loading operation when the vessel’s tank pressures are typically higher than they normally are at any other stage of the voyage. During the loading operation all of the vessel’s compressors will normally (more)
    marinetales April 6, 2021
    Gross tonnage Gross Tonnage is a measure of the ships total interior volume and is calculated by multiplying the interior volume “V” of the ship in cubic meters by a variable known as “K” (which varies depending on the ships overall volume). Gross Tonnage is not to be confused with Gross Registered Tonnage which is explained below. Net tonnage Net Tonnage is a measure of the total interior volume of a ship’s cargo spaces and is calculated in much the same way. The total volume of designated cargo spaces in cubic meters is then multiplied by varied number of factors (more)
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