WHAT IS PURPOSE OF TAPPET CLEARANCE & HOW IT IS DONE

Q)WHAT IS PURPOSE OF TAPPET CLEARANCE & HOW IT IS DONE?

ANS) Tappet clearance is a space between the top of the valve stem and the rocker arm. Its purpose is to allow for some mechanical expansion and lengthening of the valve stem and push rods as the engine warms up. This clearance is also called valve lash.

If insufficient(lower clearance) valve lash is set when the engine is cold the valves will not properly close when the engine warms up or early opening of the valve.. If too much lash is provided (additional clearance) then even after the engine warms up there will be some clearance, which will result in lost motion. Lost motion mean that as the cam tries to open the valve the push rod and rocker arm moves to first take up the clearance before touching the valve to open the valve. The result is late opening of the valve.

When checking tappet clearance on marine engines, we have to ascertain that the piston is at TDC. Though markings are provided on the flywheel, the marine engineer must know the other methods for this like inspection of the camshaft and the fuel pump window.

During the maintenance of a four stroke marine diesel engine there are times when we must know whether the particular unit’s piston is at the top dead center or not. For example when checking the tappet clearances of the engine it is important to know which unit is at TDC.

Referring to the flywheel would indicate two units, but only one can be at injection TDC. So which one is it?

Flywheel Method: -

The flywheel is the simplest method to know which unit is at TDC. If the flywheel shows two units, simply open the bonnet covers and checks visually. The unit at TDC will have both the inlet and the exhaust valve closed and hence relaxed springs; the other unit would have both the armsof the rocker arm at different levels. In addition the push rods of the unit at TDC would be loose and can be turned by hand because of the release of the clearances. There is a word of caution however: this method is only useful in a working generator, which you have just stopped to check the tappet clearances. In case you have removed the rocker arms for any reason the spring height and the push rod freeness check would lead you nowhere and misguide you.

In this method the fuel injector is taken out and from the opening a dial gauge is put inside. Then the turning gear is engaged and the engine turned over. The pointer of the dial gauge will move in one direction and then stop and start in opposite direction. The moment the pointer of the dial gauge stops and changes its direction of movement is the TDC of the unit. This method is not normally used in day-to-day practice, but may be used in the calibration of the flywheel if it is not calibrated, or after some repairs

Camshaft Method: -

The camshaft window of the engine can be opened up and the camshaft inspected. The cam of the engine has a base circle, and acceleration and dwell periods. If the roller of the follower is at the base circle, then the particular valve is closed by spring action. When both the exhaust valve and the inlet valve follower are on the base circle, then the unit is also at TDC. It must be remembered that as a four-stroke engine has two rotations of the crankshaft there is one injection TDC where the injection and the combustion take place. The second time the piston is at TDC is when the exhausting of the flue gases takes place. It is very important to identify the combustion TDC, as tappets have to be adjusted at that point.

Crankcase Method: -

In this method the crankcase doors are opened up and the piston is visually checked whether is going up or down. This is the surest method, but a bit cumbersome. It should be used when you have a strong doubt about the other methods.

Valve Spring Method: -

This is not an independent method but is used in conjunction with the flywheel method. In this method if the flywheel is indicating two units, you can check the springs of both the units. The unit in which the springs are loose is the one at TDC. The caution is that this method is useful for an engine in use. If you have removed the rocker arms during the overhaul and thereafter you want to use this method then it can cause errors.

Push Rod Method: -

This method is like the spring method and you check that the push rods are free to turn. The unit at TDC will have loose springs. The care that must be taken is that it should be used along with the flywheel method and should be used in a working engine. By a working engine, I mean the engine that was running and has been stopped for tappets adjustment.

Loosen the lock nut of the rocker arm.

TAPPET ADJUSTMENT:

Now adjust the tappet clearance between the rocker arm & valve stem by tightening or loosing the nut below the lock nut.

If tappet clearance is less:

I. Valve will open early & close late

ii.Air induced through inlet valve may leak out. So less air for combustion.

iii.Power will be reduced.

iv.Fuel consumption will increase, engine may become unbalanced, exhaust temp. will be very high.

v.In worst condition, valve may remain open, resulting in loss of compression pressure, burning of exhaust valve, T/C fouling will increase.

If tappet clearance is more:

I. Valve will open late & close early.

ii.Lesser heat energy to T/C, so reduction in scavenge air & hence power.

iii.No proper removal of gases.

iv.Hammering of valve stem-may cause damage to valve stem.

Previous year oral question on PISTON.

Q)HOW WILL YOU DECIDE TO CHANGE THE PISTON RING?

ANS)

1.BY CHECKING THE BUTT CLEARANCE. IF ITS VALUE HAS BEEN INCREASED THAN THE NORMAL RANGE.

2.IF ITS AXIAL CLEARANCE HAS BEEN INCREASED THAN THE NORMAL RANGE.

3.BY CHECKING THE VISUAL CONDITION OF PISTON RING.

Q) WHAT ALL CHECKS TO BE DONE ON PISTON?

ANS)Piston inspection on ships is part of the engine planned maintenance schedule (PMS) carried out to ensure the components is within the allowed tolerances. There are two methods of inspection: when the piston has been removed from the liner or inspection through the liner scavenges ports.

a)Piston Removed for Inspection:-

This examination will be under taken in a modular format, since the piston can be divided into various components.

Piston Crown

Check for any burning at top part of the piston.

Check any wear at the sidewalls of the crown and on ring grooves.

Check for any cracks at top due to the thermal and mechanical stress, check also for high temperature corrosion.

Check any signs of hot corrosion at the top surface and acidic corrosion at the lower part.

Piston Rings and Grooves

Check for the free movement of the piston rings. Check the ring clearance / groove clearance. Inspect for any wear, stepping and for scuffing.

Piston Skirt and Side-wall

Check for any rubbing marks.

Inspect for any wear down of wear rings.

Cooling Water Passage

Check for any scale due to poor water treatment. Choking due to high temperature.

Finally inspect the locking bolts; wires, studs and ‘O’ ring conditionb)Maintenance Schedule:-

Periodic inspection has to be done when the engine is not running. It can be carried out as above or by entering the scavenge space and inspecting the piston and piston rings through the scavenge ports, with the piston brought in line by rotating the engine via a turning gear.

Overhauling the piston as per Planned Maintenance Schedule (PMS).

Monitoring of the condition of the piston and the piston rings by the compression curve of the indicator diagram through process analysis.

The images shown below show examples of two means of inspection.

Inspection of piston and rings through the scavenge port 

Emergency Repair of Piston Crown:-

Once the above checks have been carried out, what actions can be taken if some values or observations are out with the specifications? Given below is a list of common faults that might be found during inspection and means to make temporary emergency repairs.

Gauge piston crown and ascertain shape and wear-down. If it is beyond recommended limits, replace the piston if there is a spare available. If not, rebuild the engine and proceed to the nearest port at reduced revolutions and arrange replacement. The crown head should not be welded except in a dire emergency- and even then only by an experienced welder. Remember that modern diesel engine pistons have a special lining of high temperature alloy on the top of the crown. This measure improves resistance to corrosion as well as to high combustion temperatures that the piston top is exposed to

Examine the crown for fractures or cracks, and if found the piston should be changed. If no spare is available these can be welded to manufacturer’s specifications; using the correct alloy welding rods, again as a means to proceed to the nearest port at reduced revolutions for a replacement.

Dismantled piston rings should be kept in sequential order so as not to interchange the rings when re-fitting to the piston.

Once repairs are complete, replace the piston rings and check for normal butt clearance.

If the butt clearance is more or less than the normal range, then replace the piston rings with new set of piston rings.

Note: It would be an extraordinary predicament to be in where as a Chief Engineer you sailed without main engine piston spares. However, strange things happen at sea, maybe the spares have been already used, and you're awaiting delivery of replacements.

If any of the above repairs are carried out, it is imperative that a close watch is carried out on the appropriate cylinder with the exhaust temperatures closely monitored as well as the piston cooling medium temperatures.

PROCEDURE FOR OVERHAUL OF A/E

PROCEDURE FOR OVERHAUL OF A/E?

D'carb of auxiliary engine is nothing but the carrying out of certain routines at intervals prescribed by the manufacturer or experience. Normally the following should be done during a marine decarb to free the engine from anomalies

Every 3000hrs

1. take out cylinder head, take the worn out mountings and/or over haul the mountings

2.All units cylinder head, piston, connecting rod, and 3.turbocharger to be overhauled

4.Clean sump tank and fill with fresh lube oil

5.Take crank shaft deflection before and after removal of bearings

6.Whatever actions taken should be recorded in the maintenance record book

D'carb preparation:-

1.Make sure the all stand by auxiliary engines are ready 2.Keep all the special tools and other tools ready

3.Go through the previous records/manual for clearance

4.Put the display card "MEN AT WORK", "DON'T START"

5.Close air bottle valve to auxiliary engine and engine start and stop valve

6.See that the turning bar is not in the flywheel and should be in place

7.Open the indicator cocks

8.If the main bearing is to be removed, check crank shaft deflections

9.Close lube oil, fuel oil, fresh water inlet/outlet valve, drain the cooling water line and remove connections

A)Removal of cylinder head:-

Scavenge manifold, exhaust manifold , rocker arm, lube oil drain connection from rocker arm, rocker arm tank and cover connection to be removed

Fuel oil high pressure connection from fuel pump to the injector, fuel valve cooling connections in and out (either diesel or water) to be removed

Remove the rocker arm assembly and the push rod. Remove all the mountings such as starting valve, indicator cock, relief valve and exhaust valve assembly

Remove the rocker cover and check any marking on cylinder head nuts and studs. If no torque spanner is available, note down the markings.

Open the cylinder head nut with box spanner and extension rod. Never use the torque spanner. With box spanner available note down the marking.

Put the cylinder head lifting tool and before lifting make sure all the connections are removed. Also ensure that the liner is not removed along with the cylinder head

Take out the copper joint between the head and the liner

Removal of piston and connecting rod:-

After lifting the head, check the liner surface for score marks, blow past etc. Crack remove the ridges or deposits if any on the top surface to avoid the lifting of liner along with the piston and breakage of piston rings while lifting piston

Open the crank case door and remove the bottom end bearing bolts after removing the lock arrangement and the remove the bolts

Remove the bottom half of the bottom end bearing

Bring the piston to TDC. Make sure the bolt holes on the piston top; lifting tool holes must be cleared from carbon deposits. Threads should also be checked and cleared

Put the piston lifting tools and tighten the bolts

Lift the piston and remove top shell of bottom end bearing

Place the piston on the piston stand and cover the crankcase pin to avoid the foreign material damaging the crank pin.

PISTON WITH RINGS B4 CLEANINGPISTON WITHOUT RING B4 CLEANING

Cleaning the carbon content on all the parts of engine:-

Clean the piston rings, measure dimensions and keep them in order

Clean the piston ring grooves thoroughly and measure the groove thickness at 3 different points

Check for the deposits on piston crown (Sulphur, carbon or thick vanadium deposits) and measure the dimensions

Remove the gudgeon pin and clean the gudgeon lube oil holes as well as the bush or small end bearing

Check the bolts of connecting rod for any cracks

Every 20,000 hrs engine connecting rod bolt must be replaced

If new piston rings are going to be replaced, then there is no need for measurement

Calibrate the liner thickness by using template Assembly of the engine parts:-

First put the piston rings one by one and measure the butt clearance for all the rings

Then measure the axial clearance between piston rings & grooves

Place the piston guide on top of the liner and bring the particular crankshaft to TDC. Apply sufficient lube oil and start lowering the piston. Make sure that butt gap should not be in line it may cause blow past

Before engaging check the crankpin for any cracks or scratch

Check the bottom end bearing clearance and if needed measure the main bearing clearance as well

Taper clearance is checked

Check for any cracks in the water jacket and in the cylinder head

Replace all rubber joints and copper gasket to be put on the cylinder cover

Put the cylinder head gasket in the top of the cylinder

Anti-seizure coating or powder like molycote, copper slip should be used. It is applied to avoid any seizure mainly on the threads or joints and it will be easier while removal

Tighten the cylinder mounting according to torque specified as in manual and make all connection like lube oil, fuel, jacket cooling water connections etc

Fit the rocker arm back

DECARB IS DONE TO INCREASE THE EFFICIENCY OF ENGINE.

MEO CLASS IV ORAL QUESTIONS WITH ANSWERS (Part-1)

Q: WHAT IS CAMBER?

ANS) The camber is a measure of lateral main deck curvature in naval architecture.

The practice of adding camber to a ship's deck originated in the era of small sailing ships. These vessels were built with the decks curving downwards at the sides in order to allow water that washed onto the deck to spill off.

Q:WHAT IS TUMBLEHOME?

ANS)In ship designing, the tumblehome is the narrowing of a ship's hull with greater distance above the water line. Expressed more technically, it is present when the beam at the uppermost deck is less than the maximum beam of the vessel.

A small amount of tumblehome is normal in many designs in order to allow any small projections at deck level to clear wharves (structure on the shore of a harbor where ships may dock to load and unload cargo or passengers)

Length overall (LOA) is the extreme length from one end to the other.

Length at the waterline (LWL) is the length from the forward most point of the waterline measured in profile to the stern-most point of the waterline.

Length Between Perpendiculars (LBP or LPP) is the length of the summer load waterline from the stern post to the point where it crosses the stem.

Beam or breadth (B) is the width of the hull. (ex: BWL is the maximum beam at the waterline)

Depth or moulded depth (D) is the vertical distance measured from the top of the keel to the underside of the upper deck at side.

Draft (d) or (T) is the vertical distance from the bott om of the hull to the wate rline.

Freeboard (FB) is the difference between Depth and draft

Q: EXPLAIN MOULDED BREADTH, MOULDED DEPTH, AND DRAUGHT?

ANS)Breadth (extreme):

The extreme breadth, recorded in meters to two decimal places. This is the maximum breadth to the outside of the ship's structure.

Breadth (moulded):

The moulded breath, recorded in meters to two decimal places. This is the greatest breadth at amidships from heel of frame to heel of frame. This will only be displayed when breadth extreme is not available.

Moulded Depth:

The moulded depth, recorded in meters to two decimal places. This is the vertical distance at amidships from the top of the keel to the top of the upper deck beam at side.

Draught:

The draft (or draught) of a ship's hull is the vertical distance between the waterline and the bottom of the hull (keel), with the thickness of the hull included; in the case of not being included the draft outline would be obtained. Draft determines the minimum depth of water a ship or boat can safely navigate. The draft can also be used to determine the weight of the cargo on board by calculating the total displacement of water and then using Archimedes' principle. A table made by the shipyard shows the water displacement for each draft. The density of the water (salt or fresh) and the content of the ship's bunkers have to be taken into account. The closely related term "trim" is defined as the difference between the forward and after drafts.

Q: WHAT IS RECENT AMENDMENT TO SOLAS WITH RESPECT TO MSDS, LIFEBOAT & ETA?

ANS) MSDS: MATERIAL SAFETY DATA SHEET: DATE OF ENTRY IN FORCE: 01-JULY-2009

AMENDMENT OF OCTOBER 2007 TO SOLAS: -

Amendment to SOLAS chapter 6, to add new regulation 5-1 on material safety data sheet (MSDS) to require ships carrying MARPOL Annex 1 cargo (oil) & also marine fuel oils to be provided with material safety data sheet prior to loading such cargoes. The regulation refers to the Recommendations for material safety data sheet (MSDS) for MARPOL Annex 1 cargoes & marine fuel oils, adopted by the organization through resolution MSC 150 (77)

Prevention of accidents involving lifeboats: -

An amendment to SOLAS regulation III concerns provisions for the launch of free-fall lifeboats during abandon-ship drills. The amendment will allow, during the abandon-ship drill, for the lifeboat to either be free-fall launched with only the required operating crew on board, or lowered into the water by means of the secondary means of launching without the operating crew on board, and then maneuvered in the water by the operating crew. The aim is to prevent accidents with lifeboats occurring during abandon-shipdrills. The amendment is expected to enter into force on 1 July 2008.

Q: WHAT ARE THE SAFETY FEATURES IN AIR COMPRESSORS?

ANS)Every Air compressor on a ship is fitted with several safety features to avoid abnormal and dangerous operational errors of the equipment. If safety, alarms and trips are not present on the air compressor, abnormal operation may lead to breakdown of the compressor and may also injure a person working on or around it.

1.Relief valve: Fitted after every stage to release excess pressure developed inside it. The setting of the lifting pressure increases after every ascending stage.

2.copperBursting disc:A bursting disc is a copper disc provided at the airside of the compressor. It is a safety disc, which bursts when the pressure exceeds over the pre- determined value.

3.Fusibleplug:Generally located on the discharge side of the compressor, it fuses if the air temperature is higher than the operational temperature. The fusible plug is made up of material, which melts at high temperature.

4.Lube Oil low-pressure alarm and trip:If the lube oil pressure goes lower than the normal, the alarm is sounded followed by a cut out trip signal to avoid damage to bearings and crank shaft.

5.Water high temperature trip:If the intercoolers are choked or the flow of water is less, then the air compressor will get over heated. To avoid this situation high water temperature trip is activated which cut offs the compressor.

6.Water no-flow trip:If the attached pump is not working or the flow of water inside the intercooler is not enough to cool the compressor then moving part inside the compressor will get seized due to overheating. A no flow trip is provided which continuously monitor the flow of water and trips the compressor when there is none.

7.Motor Overload trip:If the current taken by motor during running or starting is very high then there is a possibility of damage to the motor. An overload trip is thus fitted to avoid such situation

8.High Air Temperature Trip

Meo class IV oral Questions. Mumbai MMD

Meo class IV oral Questions.

how does a hatch cover operates n how it prevents sea water going inside hatch?

duct keel construction

entry procedure for duct keel

ism code n doc n smc

tender ship

why jacket cooling water in m/e flow from bottom to top

g/e fuel cam worn out ur action

why air distributor cam s negative

butt clearence

moisture in refigeration system

centrifugal pump ohaul

procedure for main sea water p/p filter cleaning

bumping clearence

1. which ship you did?

draw cross section of your ship.

2. whats regulation regarding garbage, many cross questions on that

3.boiler back fire,why how and how to prevent, factors affecting that,

4.what is pitch circle diameter, if you have a flange with four holes in it..what is its pcd means.

5. boiler water treatment, in detail, what test you used to carry onboard, name the chemicals..procedure for each test, chloride, alkalinity, value of chlorides , alkalinity, ph,what if chloride increase..what if alkalinity increase , decrease , what actions you , would take in each case,

6. how to take tappet cleareance, position of piston for that, why that postion, if there are no marks on flywheel how will you know the position of unit.

.draw card for leaky exhaust valve

8.turbocharger surging , what factors can cause it,

9. what is volumetric efficiency , whats the equation for that

10. what type of fuses you used on board, how to test a fuse .

11. types of starters, which motors on your ship used which kind of starters

1. which ship you did, there is some regulation regarding bulk carriers ..what is it. he asked in detail,

2. safeties of auxillary engines,in detail, he kept telling me ..there are more ,

3. what are machineries supplied from esb,

fuel pump timing,air distributor in man b&w mc engine,starting air line safety, boiler blow down,how will u know that ism code is followed in ur engine room while taking round

msb trips,esb safety,types of fuses used in engine room,megger,whta wil b d megger reading wen connected across sam phase,how to test fuse..

1. what are all supplies provided from emergency switchboard?

2.MSB safeties.....he doesnt want all trips breakers etc....just mention d handle,rubber mat,gap at behind and deadfront type...

3.single phasing and its effects?

1.Hazards related to crude oil?

2.forward iccp fails...hw will u prevent hull fouling?

3.freon gas bottle construction?

4.hazards on oil tanker, in which category they came.

Prop shaft drawing

Rudder carrier drwg

Lb lowering

Deadman handle

Sox nox reg

Stablizers wat n whr

Governor . Purpose

Turbine blade profile

P n t at hp inlet n.xover n lp outlet

Boiler water tests

Bedding of prop. N how to increase

Safety vv drawing

Fuel injector drawing

Starting air system from local control n hw fuel starts to go in as u move handle to dead slow

Crankcase insp

Unit decarb.. Wat all measurements to take

Piston ring butt clearence measurement

Boiler manhole door. Whr is ut fitted

Boiler drawing of ur ship

How to do superheat control

Main Engine safety devices

 

Engine Safety Devices

The main engine safety devices are provided in the system to safeguard the main engine in case of any damage in the system Mainly are fitted in engine when all the alarm and trips fails to work then the last means for safeguarding the engine and components is these safety devices fitted in the main engine .These are mainly of the type of pressure relief valve which release the excess pressure built in case of malfunctioning of the engine and no action is will in advance to rectify or to avoid the situation

SOME OF THE MAIN ENGINE SAFETY DEVICES FITTED IN THE MAIN ENGINE :

●      Crank case Relief Door

●      Scavenge Space Relief Door

●      The Starting Air LIne Relief valve .

●      Cylinder head Relief valve

●      Flame trap.

●      Oil mist detector.

●      Running Direction Interlock

●      Turning gear Interlock.

Main Engine Slow Down

Main engine slow down automatically when there is problem in the system and to avoid the greater damage in the later stages when these defects are rectified the engine automatically tunes to the sea speed .This is the primary stage to rectify the defects and it also indicates there is a great damage to be taken place so rectify the defects as early as possible .

Main Engine Safety Trips :

Main engine safety trip which trips the main engine when no corrective action is taken to the alarm and in certain cases the main engine is tripped manual .

Manual tripping of main engine is done in chance of the collision or grounding of the ship when sailing in congested water and in navigation of the ship in restricted visibility .

So when any main engine trips are activated the Main engine stops and again it should be started with the help of starting air after correcting the faults .

SOME OF THE MAIN ENGINE TRIPS ARE :

1.   Over Speed Trip

2.   Low Lube oil pressure Trip

3.   Camshaft Lube oil low pressure Trip

4.   Jacket cooling water low pressure Trip

5.   Piston cooling water low pressure Trip

6.   Thrust Bearing High pressure Trip

7.   Main Bearing high pressure and temperature Trip.

8.   Oil Mist Detector

9.   Spring air pressure Low Trip

10. Emergency Manual Trip.

 

 

 

Safety Questions meo classIV

1,What Do You Mean By Priming Of Pumps?

 Ans:The Pump Should Be Full Of Liquid Between Suction Valve And Discharge Valve And Any Air In The Pump Should Be Purged Through Venting Pump

 

2,What Is An Eductor? What Is It?s Use Onboard?

Ans: An Eductor Is A Non Mechanical Pump Which Consists Of Water Jets Supplied From Some  High Pressured Pump Discharging Into Suction Chamber Which Is Connected To A Suction Line.the High Pressure Jet Discharged From The Nozzle Entrance.

 

3,What Are The Classes Of Fire?

      Ans:

            Class A-carbonaceous Materials(wood,paper,etc)

            Class B -liquid Fire,oil Fire

            Class C-gaseous Fire,electrical Fire

            Class D-metallic Fire(magnesium, Potassium)

 

4,What Are The Causes Of Fire In E/r?

    Ans:   Free Air Flammable Materials Are Readily Available In The E/r Only Heat Is Required Which Can Be Generated By

                I. Electric Spark

                Ii. Leakage Of Exhaust Gases

                Iii.Spontaneous Combustion

                Iv.Friction(overheating Of Moving Parts)

                V.Radiations(valve,hot Pipe)

                Vi.Portable Lights

         Vii.Hot Works Such As Welding,grinding,drilling,cutting,etc(flammable Sibstances Such As L.o.f.o,e/r Waste,oil Fumes,paints Etc)

 

5,What Classes Of Fire May Occur In E/r?

        Ans:  Class B And Class C Fires.

6,What Action Will You Take Incase Of Fire In The E/r?

Ans: Duty Engineer, inform Bridge and Run to the Fire Station If Fire Is Uncontrolled, If Small Fire Extinguish Fire with Appropriate Fire Extinguisher

 

7,Where Are Fire Hoses Located In The E/r?

   Ans:  On The Bottom Platform 2 Nos(one Port Side-one Stbd Side),in fire Hose Boxes Near The Fire Hydrant And One On Top Platform As Fitted As Per Ship?s Fire Plan

 

8,What Is International Shore Coupling?

        Ans: It Is A Coupling That Match With Any Shore Connection When The Ship Is In Any Port/dry Dock To Lake Shore Water Supply And Connect It To Ship\'s Fire Line

 

9,When Will You Use Co 2 Extinguisher In E/r?

        Ans: When There Is An Electrical Fire In The E/r

 

10,When Do We Use Fixed Fire Fighting Appliance?

        Ans:  When Fire Cannot Be Put Off With Portable Extinguishers When Co 2 Flooding Is Operated .

 

11,Who Operates Fixed Fire Fighting Appliance?

       Ans:  Chief Engineer Is Solely Responsible And It Is He Who Decides To Use The Co2 Flooding System.

 

12,What Do You Mean By Co2 System?

      Co2 System Is A Fixed Fire Fighting System Used In Case Of Major Fire And It Is Meant To Flood The Engine Room In One Short After The Engine Room Personnel Are Out And All The Ventilation And Openings Are Sealed.

 

13,How Will You Fight The Electrical Fire In The Engine Room?

      Ans:  Shut Off Supply To The Circuit And Fight Fire With Portable D.c.p Co2 Cylinder.

 

14,When Will You Use Water Type Extinguisher?

      Ans:  On ?a? Class Fire.

 

15,What Is A Smoke Helmet ? When Will You Use It?

   Ans:  It Is A Fire Proof Helmet With Lighting Arrangement And It Is Used To Fight Fire In A Smoky Atmosphere.

 

16,When Will You Use A D.c.p Extinguisher?

     Ans:   To Be Used On Class A, Class C And Electrical Fire.

 

17,What Are The Sources Of Electricity On Board?

        Ans: Main Generator, Emergency Generator And Battery Pack.

 

18, Define Conductor?

      Ans:  Substances Which Allow The Flow Of Current Through It.

 

19,Define Insulators?

      Ans: Substances Which Does Not Allow The Flow Of Electricity Through It. Eg- Rubber , Mica, Paper, Wood Etc.

 

20,What Is Importance Of Emergency Generator On Board And Where It Is Fitted?

    Ans:  In The Event Of Main Generator Failure/ Blackout, Emergency Generator Causes Load Automatically And Gives Essential Supply For Navigational Equipments, Lighting. It Is Situated Outside The E/r.

 

21,State Various Dangers Association With Electrical Installations?

   Ans:  Short Circuit ? Due To Loose Connections And Overheating.Single Phasing- Due To Over Loading,improper Using, Improper Earthing,improper Mcb, Loose Connections.

 

22,State The Uses Of Battery On Board?

        Ans:    Supply Power To:-

A.       Start Emergency Generator

B.      For Emergency Generator

C.       Navigational Equipments And Lighting

D.      Alarms

E.       Communication/gmdss.

 

23,State The Uses Of Multimeter?

     Ans:  To Measure Voltage, Current, Resistance, To Find Out Short Circuit, Open Circuit Etc.

 

24,What Action Will You Take In Case Of Fire In Electrical Appliance?

      Ans:  Switch Off Supply, Disconnect From Socket And Put Off Fire With D.c.p Co2 Extinguisher.