Question and Answers

    Question
    marinetales May 17, 2021
    There are three types of Twistlocks: 1. Manual twistlock 2. Semi - automatic twistlock 3. Fully - automatic twistlock
    marinetales May 17, 2021
    The mandatory marking on ship's hull include - 1. Ship's Name 2. IMO Number 3. Port of Registry 4. Plimsoll Mark 5. Draft Marks 6. Other markings such as marking of compartments, fuel oil tanks, tug position and pilot ladder.
    marinetales May 17, 2021
    The Hong Kong International Convention for the Safe and Environmentally Sound Recycling of Ships, 2009 (the Hong Kong Convention), was adopted at a diplomatic conference held in Hong Kong, China, from 11 to 15 May 2009, which was attended by delegates from 63 countries. The Convention is aimed at ensuring that ships, when being recycled after reaching the end of their operational lives, do not pose any unnecessary risks to human health, safety and to the environment. The Hong Kong Convention intends to address all the issues around ship recycling, including the fact that ships sold for scrapping may contain environmentally hazardous substances such as asbestos, heavy metals, hydrocarbons, ozone-depleting substances and others. It also addresses concerns raised about the working and environmental conditions at many of the world's ship recycling locations.
    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 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 17, 2021
    Pooping occurs mostly on ships ( with a low heightened poop deck) when the stern sea waves are coming from astern of the ship ( the ship has following seas) resulting in hitting the poop deck. This may result in swamping the poop deck repeatedly. Check the figure as shown-
    marinetales May 14, 2021
    Centrifugal pumps are used as ballast/fire pumps. The main reasons are: 1. centrifugal pumps are usually specified for higher flows and for pumping lower viscosity liquids 2. less frictional losses 3. minimum wear
    marinetales May 14, 2021
    Following information is mostly submitted to the port prior arrival: 1. Crew list 2. Crew effect declaration 3. Bond and store declaration 4. Maritime declaration of health 5. Cargo manifest / declaration 6. Custom forms
    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
    When the Life Raft inflates the excess pressure is released from the Pressure Relief Valve. Also during the high ambient temperature the excess pressure is released from the Pressure Relief Valve. Stabilizing pockets are small pockets attached at the underside of the life raft. They fill with water and prevent the life raft from capsizing. They provide stabilization to the life raft. Pic attached below.
    marinetales May 14, 2021
    When the density of the water changes the underwater volume of the vessel changes. As a result of change in the underwater volume, the draft of the vessel changes.
    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 May 13, 2021
    SEEMP is a ship specific plan made by the owners/managers. The plan needs to be approved by the Classification Society. The SEEMP is a plan which is ship specific and has to be implemented according to the ship type, cargoes carried, ship routes, and other relevant factors. Hence, SEEMP cannot be implemented on a company or fleet level. Even two sister ships will have a different SEEMP.
    marinetales May 13, 2021
    I presume we are talking about wet chemical type extinguishers used in extinguishing deep fat fryer fires. Wet Chemical fire extinguishers contain a liquid extinguishing agent which is used to smother fires ignited from cooking oils and fats. Wet chemical fire extinguishers are filled with potassium, which cools and lowers the temperature of the fire, therefore stopping the fire from spreading.
    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 Oil Sea Interfaces including Lubrication Discharges from Paddle Wheel Propulsion, Stern Tubes, Thruster Bearings, Stabilizers, Rudder Bearings, Azimuth Thrusters, and Propulsion Pod Lubrication, and Wire Rope and Mechanica l #Equipment Subject to Immersion] Distillation and Reverse Osmosis Brine Elevator Pit Effluent Firemain Systems Freshwater Layup Gas Turbine Washwater Graywater (except certain commercial vessels operating in the Great Lakes) Motor Gasoline and Compensating Discharge Non-Oily Machinery Wastewater Refrigeration and Air Condensate Discharge Seawater Cooling Overboard Discharge (Including Non-Contact Engine Cooling Water; Hydraulic System Cooling Water, Refrigeration Cooling Water) Seawater Piping Biofouling Prevention Boat Engine Wet Exhaust Sonar Dome Discharge Underwater Ship Husbandry Welldeck Discharges Graywater Mixed with Sewage from Vessels Exhaust Gas Scrubber Washwater Discharge.[5] Approximately 69,000 vessels, both domestic and foreign flagged, are covered by the VGP.
    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 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. Sea stabilisation mode gives the navigator a better understanding about the aspect and therefore is used in collision avoidance.
    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
    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 or the loss of stability due to damaged compartments.
    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. Multipath Echoes: The echo may be reflected a number of times between the keel and the seabed, thereby giving multiple depth marks on the record, in such case the first echo is the correct depth. 3. Pythagoras error: This error is found when two transducers are used one for transmission and other for reception. 4. Thermal and Density layer. The density of the water varies with temperature and salinity, which will tend to form different layers. It is possible for echoes to return from the surface of these layers and a faint line appears between zero and actual depth. 5. Zero line adjustment error If the zero adjustment is not correct, the depth recorded will not be correct. 6. The velocity of acoustic wave changes if temperature, salinity or pressure changes and since velocity is not correct, the depth recorded will be inaccurate.
    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 from cargo pump-room bilges on oil tankers; and .5 the oily mixture, in case of oil tankers, is not mixed with oil cargo residues. B Discharges in special areas 3 Any discharge into the sea of oil or oily mixtures from ships of 400 gross tonnage and above shall be prohibited except when all of 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 14.7 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 from cargo pump-room bilges on oil tankers; and .5 the oily mixture, in case of oil tankers, is not mixed with oil cargo residues. 4 In respect of the Antarctic area, any discharge into the sea of oil or oily mixtures from any ship shall be prohibited. 5 Nothing in this regulation shall prohibit a ship on a voyage only part of which is in a special area from discharging outside a special area in accordance with paragraph 2 of this regulation. C Requirements for ships of less than 400 gross tonnage in all areas except the Antarctic area 6 In the case of a ship of less than 400 gross tonnage, oil and all oily mixtures shall either be retained on board for subsequent discharge to reception facilities or discharged into the sea in accordance with the following provisions: .1 the ship is proceeding en route; .2 the ship has in operation equipment of a design approved by the Administration that ensures that the oil content of the effluent without dilution does not exceed 15 parts per million; .3 the oily mixture does not originate from cargo pump-room bilges on oil tankers; and .4 the oily mixture, in case of oil tankers, is not mixed with oil cargo residues.
    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 climates where fog is more common, it may last all day. Mist is similar to fog except it may appear more ragged and forms on rainy days with the air saturated due to the amount of moisture. Mist is more common in mountainous and forest regions. Dew is moisture that condenses at the ground level. The layer of air within about a metre above the ground experiences rapid changes in temperature from day to night. Therefore the temperature may be cooler on the ground than the air above. Consequently, the air temperature close to the ground may cool to below the level needed for condensation. Moisture therefore is observed on grass and on the surface of some objects such as those with metal surfaces. If the air above also cools below the condensation level, fog will form.