CÂU hỏi PHỎNG vấn sỹ QUAN(ORAL EXAMINATIONS FOR THE MASTERS)

JISS ORAL EXAMINATIONS FOR THE MASTERS ELECTRONIC NAVIGATION AND PRINCIPLE OF NAVIGATION What is RADAR range resolution? - Range resolution is the ability of radar to resolve between two targets on the same bearing, but at slightly different ranges The degree of range resolution depends on the width of the transmitted pulse, the types and sizes of the targets, and the efficiency of the receiver and the indicator What is bearing range resolution? - Bearing, or azimuth, resolution is the ability of a radar system to separate objects at the same range, but at slightly different bearings The degree of bearing resolution depends on radar beam width and the range of the targets The physical size and shape of the antenna determines beamwidth Two targets at the same range must be separated by at least one beam width to be distinguished as two bi distinguished as two objects Give examples of radar false echo - The third class of non-precipitation echoes is false echoes These can occur when variations in air density cause the radar signal to refract (or bend) into the earth The reflected signal is then refracted back to the dish where it shows up as a very strong echo This situation is rare, but it has been observed a Ghost echoes b Multiple echoes c False echoes caused by side lobe d Distant false echoes caused by duct phenomenon (Vat bat thuong-Skiff) Explain radar side lobe effects? - An antenna’s side lobe emissions are low power, and will not register distant targets However, if there is a strong reflecting target near your boat, it sometimes may appear as a circular-arc false echo on the screen - Side-lobe effects are readily recognized in that they produce a series of echoes (Figure B) on each side of the main lobe echo at the same range as the latter Semicircles, or even complete circles, may be produced Because of the low energy of the side lobes, these effects will normally occur only at the shorter ranges The effects may be minimized or eliminated, through use of the gain and anti-clutter controls Slotted wave guide antennas have largely eliminated the side lobe problem How will you observe gyro error? a By Polaris b By sun amplitude sight c By sun azimuth sight What is the accuracy of sextant position and GPS? Sextant – Professional sextants use a click-stop degree measure and a worm adjustment that reads to a minute, 1/60 of a degree Most sextants also include a Vernier on the worm dial that reads to 0.2 minute Since minute of error is about a nautical mile, the best, possible accuracy of celestial navigation is about 0.1 nautical miles (200 m) At sea, results within several nautical miles, well within visual range, are acceptable A highly-skilled and experienced navigator can determine position to an accuracy of about 0.25-nautical-mile (460m) GPS- the accuracy quoted by the US DoD for GPS in Standard Positioning Services (SPS) mode, available to anyone with an appropriate receiver, is 33 meters for 95% of the time This accuracy is approximately equivalent to 0.02 minutes illustrate running fix? Running fix is a position determined by the intersection of two or more lines of position established at different times, but adjusted to the same time by considering the run of the ship between the observations The run should not exceed hours in order to have, at least, a reliable distance based on ship’s speed Practically all running fixes at sea are established by two observations of the sun, taken sufficiently far apart for the azimuth to have change enough to give a good angle between the two lines; however, lines obtained from observations of any bodies can be used Example: At 0900 the navigator observed the sun and obtained an intercept of miles towards Zn 1000, using for the AP the 0900 DR At 1200 an observation for latitude gave Lat 400 – 18.0’N Course 2400, speed 12 Plot the 1200 R fix Note: Latitude is merely a special case of position The line extends in an east – west direction and hence can be used as the latitude at the time of the sight Differentiate between gnomonic chart and Mercator chart and its uses in navigation Gnomonic chart – Gnomonic charts are most often used for planning the great – circle track between points - There are three types of gnomonic charts depending on the location of the point of tangency In equatorial gnomonic chats, the point where the plane is tangent is located at some point on the equator A polar gnomonic chart is tangent at one of the poles Oblique gnomonic charts have their point of tangency at some latitude and longitude between the equator and the poles - The land features of gnomonic charts become more distorted as the distance from the point of tangency increases The most often used gnomonic charts are oblique charts with a point of tangency located in the center of an ocean basin Gnomonic tracking charts WOXZC 5270 WOXZC 5274, have their points of tangency in the North Pacific and North Atlantic Ocean basins, respectively - The chief advantage of gnomonic charts is that a straight line between two points represents the great circle between the points If you desired to proceed by great circle, all you need to is connect the points of departure and arrival with a straight line The latitudes and longitudes of points at intervals along this line may bi measured on the gnomonic chart and then transferred to a Mercator chart When these points are connected with straight lines (rhumb lines), the navigator has the “legs” of the great circle track Once transferred to the Mercator chart, the course on each leg may be determined, and the sum of the distances along each leg gives the total great circle distance - The main disadvantages of the gnomonic projection are that courses, direction and distance cannot be readily measured For these reasons, gnomonic projections are not used for day-to-day navigation and plotting, and should be used as an aid to voyage planning Mercator chart – Mercator charts are almost universally used for navigation as they have two special features Firstly, bearings (directions) plotted on the chart are true bearings and can be used directly after allowing for compass errors (these will be covered in a later article) Secondly, distances are true distances and can be measured directly so long as certain rules are followed No of GPS satellites (2 dimensional) actively use for position fixing - In order to achieve a two dimensional (2 - D) fix on the earth’s surface at least three pseudo ranges must be obtained the three microprocessor can then resolve the three range equations to remove the effects of the receiver clock offset error 10 What is the height of GPS satellite? - The satellites orbit the earth with a speed of 3.9km per second and have a circulation time of 12h sidereal time, corresponding to 11h58 earth time This means that the same satellite reaches a certain position about minutes earlier each day The mean distance from the middle of the earth is 26560 km With a mean earth radius of 6360 km, the height of the orbits is then about 20200 km Orbits in this height are referred to as MEO – medium earth satellites orbit the earth at 42300 km, which is about twice the distance of GPS satellites 11 Why taking route in Aleutian channel from and to Japan? - The route across the North Pacific to Alaska from Japan is one that is very possible and can give you the opportunity to stop at some of the remote and beautiful Aleutian Islands The typhoons become more frequent in Japan in June/July, so you heed to time your crossing so you are out of the way of the typhoons in southern Japan, but not too early in the northern Pacific to encounter bad gales and cold The currents circulate against you on this route and the weather dependent on the passage of low pressure systems These track predominately either up the coast of Japan or across from Siberia, and on through the Aleutian chain to Alaska The choice is whether to miss the western end of Aleutian Islands and try to skirt around the south side of the low pressures and so keep following winds, or head for Attu and risk headwinds en route In our experience it would be a shame to miss these remote islands on your way past and, if carefully watching the weather faxes, this can be a feasible option What is the effect of squat on the vessel? - Squat is the combination of sinkage and trim, the largest change and location of that change along the ship’s hull depending on the location of maximum change in trim - Squat is a natural phenomena as a ship moves through a restricted channel The ship displaces an amount of water equal to her own weight this water must move outward from and around the hull in all directions The water so displaced moves primarily along and under the hull and returns astern of the ship to “fill” the space left by the ship as she moves on Naturally, the faster the ship is moving, the greater the velocity of this flow under and along her hull, and the greater the velocity of this flow under and along her hull, and the greater the corresponding pressure drop as a result of that increased velocity - As the ship enters shallow water the flow of water becomes increasingly restricted due to reduced clearance under the hull If the channel is shallow and narrow, the flow of water becomes restricted both under and on one or both sides of the hull depending on the ship’s location in the channel Explain turning circle diagram (Showing which one is the advance, transfer, tactical diameter, final diameter) Advance – the distance gained in the original direction until a ship steadies on its final course Transfer – the distance gained at right angles to the direction of the original course until the ship steadies on its final course Turning Circle – the path followed by a ship’s pivot point when executing a 360o turn Tactical Diameter – the transfer involved in the execution of a single turn of 180o Final Diameter – the diameter of the turning circle that ship would scribe when turning 360 o indefinitely (Typically less than tactical diameter due to initial “kick” of the ship) Explain super refraction The distance to the radar horizon is extended Super refraction occurs in case weather with no turbulence and there is an upper layer of warm dry air over surface layer of cold moist air This increases the downward bending of the rays and thus increases the range at which contents may be detected It often in the tropics when warm land breeze blows over cooler ocean currents What is the accuracy of GPS system (2D & 3D)? (At least satellite to determine the Lat, Long, Height, time) - GPS horizontal position fixes are typically accurate to about 15 meters (50 ft) GPS uses a constellation of between 24 and 32 medium Earth orbit satellites that transmit precise radio wave signals, which allow GPS receivers to determine their current location, the time, and their velocity A GPS fix obtained by measuring the ranges from a series of a selected satellites to the receiver Ranges are determined by measuring the propagation time of the satellite data transmission The ranges measured are not true ranges, but are termed “Pseudo Ranges” since they contain a receiver clock offset error - In order to achieve a two dimensional (2-D) fix on the earth’s surface at least three pseudo ranges must be ranges must be obtained; three microprocessor can then resolve the three range equations to remove the effects of the receiver clock offset error Similarly, four pseudo ranges would be required to obtain a three dimensional (3-D) fix Under IMO, what is the maximum target can be track on the ARPA - 20 targets where automatic acquisition is provided, whether automatically or manual acquired; and - 10 targets, if only manual acquisition is provided Give examples of ARPA alarms a) Watch zone (new target) b) Tracking overload c) Collision warning d) Lost target f) System failure METEOROLOGY AND OCEANOGRAPHY What is the direction of Kurushio current? - It flows northeast from the Philippines along the eastern coast of Japan Near northern Japan, the Kuroshio merges with a cold, southeastern current The two currents become the North Pacific Current, which runs east through the Pacific Ocean and brings mild temperatures to the west coast of North America The Kuroshio Current carries tropical waters and heat energy into the temperate latitudes along the east coast of Asia Speed of kurushio current - 2.7- km/hr What is the direction of South Equatorial current? (Strongest speed of current is from Jul-October every year) - Flows east-to-west between the equator and about 20 degrees south In the Pacific and Atlantic Oceans, it extends across the equator to about degrees north - Within the southern hemisphere, the South Equatorial Current is the westward limb of the very large - scale subtropical gyres These gyres are driven by the combination of trade winds in the tropics and westerly wards that are found south of about 30 degrees south; through a rather complicated process that includes western boundary current intensification - On the equator, the South Equatorial Current is driven directly by the trade winds which blow from east to west - In the Indian Ocean, the westward - flowing South Equatorial Current is well-developed only south of the equator Directly on the equator, the winds reverse twice a year due to the monsoons, and so the surface current can be either eastward or westward What is the direction of North equatorial current? - Flows east - to - west between about 10 north and 200 north It is the southern side of a clockwise subtropical gyre Despite its name, the North Equatorial Current is not connected to the equator In both oceans, it is separated from the equatorial by the Equatorial Countercurrent (also known as the North Equatorial Countercurrent), which flows eastward The westward surface flow at the equator in both oceans is part of the South Equatorial Current Illustrate global weather pattern - Weather patterns are important in forecasting Sometimes, one is able to predicts what the next day's weather will be based on the concepts of persistence Today's weather may repeat or persist until the following day This is especially true in regions where the common weather patterns are usually consistent or unchanging atmospheric conditions This is easily seen in warm regions where summers are consistently warm for several months - The resulting wind patterns in the northern hemisphere would be with northerly winds moving out from the poles down to about 60 degrees, a southerly wind from 60 to 30 degrees and a northerly from there to the equator The reverse would be true in the southern hemisphere Illustrate dangerous and navigable semi-circle North spheroid Typhoon avoidance in dangerous and navigable semi- circle in Northern and southern hemisphere Northern hemisphere Right of dangerous semicircle - steamers: Bring the wind on the starboard bow make as much way as possible, and if obliged to heave to, so head to sea Sailing vessels: Keep close-hauled on the starboard tack, make as much way as possible, and if obliged to heaveto, so on the starboard tack Left of navigable semicircle - Steam and sailing vessels: Bring the wind on the starboard quarter, note the course and hold it If obliged to heave to, steamers may so stern to sea; sailing vessels on the port tack Southern Hemisphere Left of dangerous semicircle - Steamers: Bring the wind on the port bow, make as much way as possible, and if obliged to heave to so head to sea Sailing vessels; Keep close - hauled on the port tack, make as much way as possible, and if obliged to heave to so on the port tack Right or navigable semicircle - Steam and sailing vessels: Bring the wind on the port quarter, note the course and hold it If obliged to heave to, steamers may so stern to sea; sailing vessels on the starboard tack Illustrate wind circulation in Northern hemisphere = towing light, 3miles = white, red, green, yellow light, all around light, 3miles a) If length is 12 ~ 50 meters = masthead light, 5miles (if length is 20 meters, miles) = sidelights, 2miles = stern light, 2miles = towing light, 2miles = white, red, green, yellow light, all around light, miles b) If length is < 12 meters = masthead light, miles = sidelights, mile = stern light, miles = towing light, miles = white, red, green, yellow light, all around light,2’ c) If inconspicuous, partly submerged vessels or objects being towed: = white all around light, miles 38.) State when lights regulated in Maritime Traffic Safety Law shall be turn on and off And state circumstances/ situations where lights shall be turn on a) The rules concerning lights shall be complied with from sunset to sunrise, and during such times no other lights shall be exhibited, except such lights as cannot be mistaken for the lights specified in these rules or not impair their visibility or distinctive character, or interfere with the keeping of a proper lookout b) The lights prescribed by these rules shall, if carried, also be exhibited from sunrise to sunset in restricted visibility and may be exhibited in all other circumstances when it is deemed necessary 39.) Make a sketch of a view as observed from dead ahead of lights Regulated in M.T.S law of a general power vessel 50m long or more During night passage 40.) Make a sketch of lights which shall be placed in the night and shapes which shall be placed in the daytime on general vessels 50m long or more during anchoring 41.) Mention what state of vessels placing spherical shapes vertically in the daytime - Not Under command 42.) Mention what kind of vessels indicating a cylindrical shape in the daytime - Vessel constrained by her draft 43.) There are three clauses on navigation rules in Law for Preventing Collision at sea One is a navigation rule on vessels are visible with each other Mention state of the other navigation rules - Conduct of vessel in any condition of visibility - Conduct of vessel in sight of another - Conduct of vessel in restricted visibility 44.) With regard to the following Article of Law for Preventing Collision at sea write phrases which adaptable in and their numbers 45.) Mention sea areas where Maritime Traffic Safety Law is applicable? a) Tokyo Wan(Bay) b) Ise Wan c) Seto Naikai(Seto Inland Sea) 46.) What are huge vessels in rules and regulations of M.T.S Law? What kind of lights shall be displayed in the night? - Huge vessels are vessels whose length is 200 meters or more In navigating traffic routes, they must give advance notification to the Maritime Safety Agency and abbey instruction given by the same Agency - An all – round green light flashing at regular intervals at a frequency between 180 and 200 per minute 47.) What kind of lights shall be displayed in vessels for emergency Performing emergency works in regulations of M.T.S Law - Vessels engaged in emergency work, such as fire-fighting operations, rescue of marine accidents, prevention or removal of marine pollution or controlling of crimes - By night: An all-round red light flashing at regular intervals at a frequency Between 180 and 200 per minute - By day: A red cone shape Apex upward 48.) What kind of lights shall be displayed in vessels carrying dangerous cargo in the night in rules and regulations of M.T.S Law - An all-round red light flashing at regular intervals at frequency between 180 and 200 per minute 49.) Mention notifications which shall be reported by huge vessels in rules and regulations of M.T.S Law a) Name of address b) Name and gross tonnage c) Call sign or call name and method of communication with Maritime Safety Agency d) Destination 50.) State the provision regarding fire alarm when a fire has broken out in vessels in specified port in Port Regulation Law - In the event of a fire having broken out on board a vessel in a specified port the vessel, if equipped with a whistle or siren, must sound five prolonged blasts repetitively - The above sound signal may not be made while under way; and the method of the alarm must be displayed in a place easily seen by persons in charge of sounding the alarm, to avoid mistakes in emergencies 51.) State the provision regarding restriction on lights in Port Regulation Law - Article 36 No person may indiscriminately use a powerful light which is feared to hamper the vessel’s traffic within a port or in the vicinity of the boundary of the port - The captain of the port may order the person a powerful light which is feared to hamper the vessel’s traffic within a specified port or in the vicinity of the boundary of the specified port to reduce or cover the light 52.) State the provision regarding restriction on smoking in Port Regulation Law - Article 36-2 No person may smoke or use fire without due care in the vicinity of an oil tanker within a port - The Captain of the Port may, when inflammable liquid is floating within a specified port as a result of a marine accident or under other circumstances and he considers that there is a danger of fire, restrict or prohibit smoking or using fire by any person in the area However, this shall not apply in the cases where Article 42-5 Paragraph of the Law Relating to Prevention of Maritime Disaster shall be applied 53.) State the provision regarding a vessel intending to load or unload good such as coal, stones or bricks which are liable to slop out in port or around boundary of port in Port Regulation Law 54.) Mention cases/circumstances when Master shall report to the minister of MILT on navigation in Mariners Law a) If a collision, grounding foundering, loss of the vessel, fire onboard, damage to the engines or other marine accident occurred (other marine accidents include those similar to the accidents enumerated above) b) If the vessel was engaged in an operation to rescue a human life or a vessel c) If it came to the knowledge of the vessel except by radio telegraph while at sea that another vessel was in distress d) If the vessel has changed her planned route e) If the person on board died or has gone missing 55.) Mention measures that a master shall take in case that the vessel under his control is in imminent dangers in Mariners Law - A Master, when there is imminent danger to his/her vessel, shall exhaust every means necessary to save a human life, the vessel and the cargo 56.) Mention measures that a master shall take in case of collision in Mariners Law - In case of collision between two vessels, each master shall use every possible means necessary for saving of the other vessel and a human life on board the vessel and give the name of his/her vessel, her owner, her port of registry, departure and destination to the master of the other vessel, expect when there is imminent danger to the under his/her command 57.) Mention documents that a master shall keep onboard under the provision of Mariners Law - The Master of the vessel shall keep onboard 1) A certificate of nationality (Ship Law Article 6), provisional certificate of nationality (Ship Law Article 13, 15, 16), navigation permit (detailed regulations for the enforcement of the ship law article 4) Certificate of registry (Cabinet Ordinance Concerning the Registry and Measurement of Gross Tonnage of Small ships, Article 1), or provisional small ship navigation permit (same cabinet ordinance Article 8-3; Regulations Article 9) 2) Shipping articles of agreement 3) Logbook 4) Passenger list 5) Document on cargo (Law Article 18; Regulations Articles through 13) Vessels other than certain passenger ships licensed to navigate waters without any limitation, near sea waters or extended coastal waters need not be furnished with a passenger list (Regulations Article 12 paragraph 2) If he has failed to keep such documents on board his vessel or if he has failed to enter required matters or made false entries in the shipping article of agreement, official logbook, or passenger list, the master shall be liable to a fine of no more than 300,000 yen (Law Article 126) 58.) Answer the following questions regarding seaman’s book under rules and regulations of Mariners Law a) Who shall hold seaman’s books of mariners on board? - Master b) How many years are seaman’s books valid after delivery, re-delivery or renewal? - The effective period of a Mariner’s pocket ledger is ten (10) years after its delivery, reissuance or renewal, but the effective period of a Mariner’s pocket ledger held by a foreigner is five (5) years 59.) With regard to the following provisions of Law for Prevention of Marine Pollution and Marine Accident, write phrases which are adaptable in and their numbers Article 2: Marine Pollution and Marine Accident The image of the question is as follows 60.) Mention what cases that any certificate of a maritime officer may be revoked in Law of ship’s officers and boat’s operators - Assault with danger weapon - Malicious destruction of ship’s property - Misconduct resulting in loss of life or serious-injury - Murder or attempted murder - Mutiny - Perversion - Possession, use, sale or association with drugs, including marijuana - Serious theft of ship’s store - Smuggling of aliens or goods - Sabotage - Court conviction of crime involving mortal turpitude 61.) Mention kinds of navigation areas of vessels prescribed in enforcement regulation of Ship’s safety Law - Smooth sea - Coastal sea - Greater coastal area - Unlimited water 62.) Mention kinds of inspections prescribed in Ship’s Safety Law - Periodical inspection: A thorough inspection to be conducted before the ship is first put into service, or when the period of validity of Ship Inspection Certificate as prescribed in Article 10 has expired - Intermediate inspection: A simplified inspection to be conducted between one periodical inspections and another at the time prescribed by the Regulations - Occasional inspection: An inspection to be conducted when modifications or repairs as specified in the Regulations as regards those matters relating to each item enumerated in Article 2, paragraph or to a radiotelegraph installation, etc take place; when the position of the load line as designated by Article 9, paragraph and the conditions mentioned on the Ship Inspection Certificate are altered; or when designated by the Regulations - Temporary navigation inspection: An inspection to be conducted when a ship which does not possess a Ship Inspection Certificate is going to engage in a temporary voyage - Special inspection: Excluding the preceding respective sub-paragraphs, an inspection to be conducted when the competent Minister deems it necessary to conduct an inspection due to unsatisfactory compliance with the conditions of Article 2, paragraph 63.) Mention kinds of disciplinary actions prescribed in Marine Accident Inquiry Law a) Revocation of a license (decision to revoke a license indefinitely) b) Suspension from duties for a period of from not less one (1) month to not more than three (3) years (decision on temporary suspension from duties) c) Reprimand (decision to warn a person for the future) 63.) Mention situations defined as marine accidents in Marine Accident Inquiry Law a) When a vessel is damaged, or when any facilities other than the vessel are damaged in relation to the operation of the vessel b) When any person is killed or injured in relation to the structure, equipment or operation of the vessel c) When the safety or navigation of the vessel is impeded 64.) Monsoon: - A wind system that influences large climatic region and reverses direction seasonally - A wind from southwest or south that bring heavy rainfall to southern Asia in the summer And wind from northeast in winter 65.) Camber 66.) Cold air into warm water: - Temperature decreasing - Atmosphere increasing - Cloudy, fog on the surface and rain maybe also appear 67.) NUC - Day time signal: two black balls in a vertical - Night time: 02 all-around red colors light in a vertical 68.) Procedure man-overboard If you witness someone going overboard: Keep your eyes on them, DON'T lose sight of them Yell: "MAN OVERBOARD" and you are closest to the Dan Buoy or Man Overboard Raft: Release the Dan Buoy or raft Yell: "DAN BUOY (or) RAFT RELEASED" Make sure the watch officer has heard you: Go to your muster station If you hear "MAN OVERBOARD" and you are in, or closest to the Deckhouse: Go to the GPS unit and push the "Man Overboard" button Yell : "PS BUTTON PUSHED" Go to your muster station If you are on the helm and you hear "MAN OVERBOARD": Be ready for the Watch Officer's instructions and carry them out Stay on the helm, but make sure the Toa knows you are there Otherwise if you hear "MAN OVERBOARD" If you not already have it on, put on the protective gear you have close to hand as quickly as possible Quickly put on your lifejacket Go to your muster station, ready to work Japan International Ship System Examination Questionnaires given by MLIT (Ministry of Land, Infrastructure, Transport and Tourism) 49) Explain and Illustrate – MO (U) G 8s (Buoy) - This Indicates that the light is Morse (U) in which color is Green (G) repeated every Eight second (8s) 50) Explain and Illustrate – East cardinal mark A cardinal mark indicates where the best and safest water may be found and is used in conjunction with a compass It shows where the mariner has safe passage A cardinal mark may indicate:  The deepest water in an area  The safe side on which to pass a danger  A feature in a channel such as a bend, junction or an end of a shoal Cardinal Mark features  Top marks: black double cones clearly separated  Colors: black and yellow horizontal bands with the position of the black band or band relative to the respective cardinal points  Lights: a cardinal mark exhibits a white light and its quadrant is distinguished by a specific group of quick or very quick flashes e) North – top mark points up, black band above yellow band - Uninterrupted flash f) East – top mark points outward, black bands above and below yellow band - Three flashes in a group g) South – top mark points down, black band below yellow band - Six flashes in a group followed by a long flash h) West – top mark points inward, black band between yellow bands - Nine flashes in a group  To assist in remembering cardinal marks, associate the number of flashes of each group with that of a clock face That means that north is at twelve o’clock, east is at three o’clock, south is at six o’clock and west is at nine o’clock  To ensure that no confusion occurs, between east, south and west marks, a long flash immediately follows the six flashes of the south mark 51) Explain – Initial stability - Initial stability is the resistance of a boat to a small amount of lateral tilting from its equilibrium position It is determined by the difference in the volume of water displaced on each side of the boat as it tilts and is relatively independent of hull shape for small angles of tilt 52) Identify star altitude & direction through a given illustration 53) What is 2nd substitute in Port Regulation law? 54) What is the safe speed in the vicinity of ports? - Article 16 A vessel shall, within a port or near the boundary of the port, proceed at such a speed as not cause a hazard to other vessels A sailing vessel shall, within a port, proceed shortening sails or using tugboats 55) Explain weather chart (Temperature) dew point Humidity is a measure of the atmosphere’s water vapor content Relative humidity is the ratio, stated as a percentage, of the pressure of water vapor present in the atmosphere to the saturation vapor pressure at the same temperature As air temperature decreases, the relative humidity increases At some point, saturation takes place and any further cooling results in condensation of some of the moisture The temperature at which this occurs is called the dew point, and the moisture deposited upon objects is called dew if it forms in the liquid state or frost if it forms as ice crystals Relative humidity and dew point are measured with a hygrometer The most common type, called a psychrometer, consists of two thermometers mounted together on a single strip of material One of the thermometers is mounted a little lower than the other, and has its bulb covered with muslin When the muslin covering is thoroughly moistened and the thermometer well ventilated, evaporation cools the bulb of the thermometer, causing it to indicate a lower reading than the other A sling psychrometer is ventilated by whirling the thermometers The difference between the dry-bulb and wet-bulb temperatures is used to enter psychrometer tables (Table 35 and Table 36) to find the relative humidity and dew point 56) - Signal in a bend (Colreg) A vessel nearing a bend or an area of a channel or fairway where other vessels may be obscured by an intervening obstruction shall sound one prolonged blast Such signal shall be answered with a prolonged blast by any approaching vessel that may be within hearing around the bend or behind the intervening obstruction 57) Signal when overtaking to port? - Two prolonged blasts followed by two short blasts to mean “I intend to overtake you on your port side” 58) What is not under command vessel? - The term “vessel not under command” means a vessel which through some exceptional circumstance is unable to maneuver as required by these Rules and is therefore unable to keep out of the way of another vessel 59) Correct navigation when navigating a bend on narrow channel - A vessel nearing a bend or an area of a narrow channel or fairway where other vessels may be obscured by an intervening obstruction shall navigate with particular alertness and caution and shall sound the appropriate signal 60) Sound signal of vessel when overtaking on portside or other vessel - Two prolonged blasts followed by two short blasts to mean “I intend to overtake you on your port side” 61) Vessel stopped in the water (Star Table) 62) Light characteristic FFLG (6s) drawing - This Indicates that the light is Fixed Flashing (FFI) in which color is Green (G) repeated every Six second (6s) 63) Stability GM (M, G, B, K, G; B; WL, WL; GZ)? - Center of gravity of a ship (G) – this is often defined as the point through which all the weight of the ship is considered to act vertically downwards - KG – the vertical height of the center of gravity above the keel - K – Usually taken to denote the keel - Center of buoyancy (B) – this is the geometrical center of the underwater part of the ship That is, it is the center of gravity of the water which has been displaced - KB – this is the vertical height of the center of buoyancy above the keel - Center of flotation (F) – this is the point about which ship heels and trims - Metacenter (M) – a vertical line through the heeled center of buoyancy crosses the line through the original, vertical center of buoyancy - Metacentric Height (GM) – this is the distance between the center of gravity and the metacenter - Righting level (GZ) – it is the perpendicular distance between G and the direction of the action of the force of buoyancy - BM – distance of the metacenter above the center of buoyancy 64) Cardinal buoy symbol, color, sounds (North)? - Same as number 2… see #2 for answers 65) Piping symbols? The pipe-fitting are the base line symbols used for pipe in conjunction with the symbology of pipe fittings valves They define not or the size of the pipe and the method of branching and coupling, but also the purpose for which the pipe will be used Symbols used for frequently end valves The type of and size of valves mechanical drawing must be assumed size and material connected pipe 66) Critical speed (What RPM)? - The critical speed is the theoretical angular velocity which excites the natural frequency of a rotating object, such as a shaft, propeller or gear As the speed of rotation approaches the objects’ natural frequency, the object begins to resonate which dramatically increases systemic vibration The resulting resonance occurs regardless of orientation When the rotational speed is equal to the numerical value ß the natural vibration then that speed is called critical speed Critical speeds in rotor-bearing systems are excited by the eccentric center of gravity of the shaft This is due to the static deflection under its own weight The excitation force from unbalance is a function of the stiffness of the shaft and the shaft speed When a rotor approaches its first bending critical speed, the phase angle between the unbalance force and the resultant deflection approaches 90 degrees The critical speed is calculated from the expression Nc = 16.8/ where is the maximum static deflection of the rotor in mm 67) How to detect EXH valve leaking - LEAKING VALVES: Leaking intake valves can be checked for defects by using the MICROPHONICS receiver and headphones with the engine running All valves would emit a sound in a very close meter and sound pattern when the probe is placed on the intake manifold opposite the intake port A suspected valve can then be positively checked, with the engine off, by brining that particular cylinder to full compression and placing the probe on the valve stem The “hiss” of escaping gas across the valve seat will be distinctly audible on the leaking valve Using the same procedure can check exhaust valves, however, signal intensity will be much greater 68) Explain MCO/MCR KW RPM3? - Maximum Continues Rating (MCR) Is defined as the maximum output (MW) that a generating station is capable of producing continuously under normal conditions over a year Under ideal conditions, the actual output could be higher than the MCR Within shipping, a ship usually operates at the Nominal Continuous Rating (NCR) which is 85% of the 90% of MCR The 90% MCR is usually the contractual output for which the propeller is designed Thus, the usual output at which ships are operated is around 75% to 77% of MCR - Maximum Continues 69) Steam turbine / Gland steam - A gland is a device used to minimize leakage of steam or air through the clearance provided between moving and stationary parts of a turbine Another term used is steam-seal, or a steam-sealing gland In general, there are three places on a turbine where sealing glands are used: d) At the high pressure ends to prevent leakage of steam to the atmosphere e) At the low pressure ends to prevent air leakage into the exhaust end of the turbine f) At nozzle and diaphragm blocks in impulse turbines to prevent leakage of steam along the shaft 70) Stern tube part? - The hole in the hull structure for accommodating the propeller shaft to the outside of the hull is called the stern tube The propeller shaft is supported in the stern tube by two bearings-one at the inner end and one at the outer end of the stern tube-called stern tube bearings At the inner end of the stern tube there is a stuffing box containing the packing gland (figure 4-4), which is generally referred to as the stern tube gland The stern tube gland seals the area between the shaft and stern tube but allows the shaft to rotate - The stuffing box is flanged and bolted to the stern tube Its casing is divided into two compartments-the forward space which is the stuffing box proper, and the after space, provided with a flushing connection, designed to maintain a positive flow of water through the stern tube for lubricating, cooling, and flushing This flushing connection is supplied by the fire main - Figure 4-4.-Stern tube stuffing box and gland 71) Hydraulic system what causes cavitation? - Cavitation occurs when the volume of fluid demanded by any part of a hydraulic circuit exceeds the volume of fluid being supplied - This causes the absolute pressure in that part of the circuit to fall below the vapor pressure of the hydraulic fluid These results in the formation of vapor bubbles within implode when compressed - Cavitation causes metal erosion, which damages hydraulic components and contaminates the hydraulic fluid In extreme cases, cavitation commonly occurs at the pump, it can occur just about anywhere within a hydraulic circuit - In the directional valve described above, the metal erosion in the body of the valve was so severe that the valve was no longer serviceable The valve had literally been eaten away from the inside, as a result of chronic cavitation – a kind of ‘cancer’ of the hydraulic system - In this particular case the cause of the cavitation was faulty anti - cavitation valves, which are designed to prevent this type of damage from occurring 72) Differentiate CYL OIL/ Lubricating Oil - Lubricating Oil - Are value-added lubricants with a carefully balanced additive system that will give outstanding deposit control, minimize sludge and varnish, and control wear under the most severe service conditions Formulated to provide the superior soot-handling and wear protection demanded by modern heavy duty diesel engines, they will help maintain longterm low emission performance Available in multi-viscosity grades that offer superior high temperature protection along with easier starting and rapid oil flow in cold weather - Cylinder Oil - Steam cylinder oils have never been formulated to a standard specification that has been agreed upon by a consortium of steam engine manufacturers It is a curious mystery of history that such a specification was never developed, but the stubborn independence of early American industrialists is probably mostly to blame However, the Skinner Engine Company developed generic guidelines for steam cylinder lubricants applicable to their line of steam engines Skinner was the last of the steam engine builders and built their last unaflow steam engine in 1983 Additionally, when water or moisture is present some type of animal fat compounding is necessary to prevent the heavy lubricant from washing off the sliding gear surfaces It was found that compounded steam cylinder lubricants also made excellent gear lubricants 73) Power factor in electricity? - Ratio of true power and apparent power (TP/AP) 74) How to get no of Poles? 75) GPS warning? - XTE: Cross track error - Arrival warning alarm - Anchoring watch alarm - Proc warning alarm - … 76) Topical Cyclone? - A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain Tropical cyclones feed on heat released when moist air rises, resulting in condensation of water vapor contained in the moist air They are fueled by a different heat mechanism than other cyclonic windstorms such as nor’easters, European windstorms, and polar lows, leading to their classification as “warm core” storm system Tropical cyclones originate in the doldrums near the equator, about 100 away from it The term “tropical” refers to both the geographic origin of these systems, which form almost exclusively in tropical regions of the globe, and their formation in maritime tropical air masses The term “cyclone” refers to such storms cyclonic nature, with counterclockwise rotation in the Northern Hemisphere and clockwise rotation in the 77.) Which factors effective to the current directions? - Wind - Form of sea bed - Form of coastal - Other current nearby …… 78.) Which is the importance thing the Master of a ship should take into the mind when embark/ disembark pilot? - Keep the Pilot boat on the lee side ... of the way of the other (ii) When both have the wind on the same side, the vessel which is to windward shall keep out of the way of the vessel which is to leeward (iii) If the vessel with the. .. the port side sees a vessel to windward and cannot determine with certainty whether the other vessel has the wind on the port or on the starboard side, she shall keep out of the way of the other... alongside, well forward of the propellers If dealing with a man overboard, always bring the vessel upwind of the person Stop the vessel in the water with the person well forward of the propellers