MEO CLASS 4 ORAL QUESTIONS ANSWER

MEO CLASS 4

External - moham

Internal - sirish

FUNCTION 3 SAFETY

BILGE KEEL

•  IT WILL REDUCE THE SHIP'S TENDENCY TO ROLL
• SHIP HAVE ONE MORE BILGE KEEL PER SIDES
• BILGE KEEL INCREASE THE HYDRODYNAMIC RESISTANCE TO ROLLING
• BILGE KEELS ARE PASSIVE STABILITY SYSTEM.

DUCT KEEL

•   DUCT KEEL IS A PLATED BOX KEEL ALLOWING PASSAGE RIGHT FORWARD.
• IT PROVIDES ADDITIONAL BUOYANCY.
• TOGATHER WITH A THROUGH PASSAGE WAY FOR THE CABLES AND PIPLE LINES RUNNING IN THE FORE AND AFT DIRECTION.

MARGIN LINE

• A LINE DRAWN AT LEAST 76 MM BELOW THE UPPER SURFACE OF THE BULKHEADS AT SIDES
• UT DEFINING THE HIGHEST PERMISSIBLE LOCATION ON THE SIDES OF THE VESSEL OF ANY DAMAGE WATER PLANE  IN THE FINAL CONDITION OF THE SINKAGE TRIM AND KEEL 

MARGIN PLATE 

• WHICH IS USED TO LEAD THE FLOW OF WASTE FLUID TOWARDS THE BILGE WELLS ON EITHER SIDES OF THE SHIP.

BALANCED RUDDER

•  ITS THE ONE WITH ABOUT 30% - 40% AREA IS FORWARD OF TURNING AXIS.

STATIC STABILITY

• IS THE ABILITY OF THE SHIP TO REGAIN ITS UPRIGHT EQUILIBRIUM POSITION AFTER REMOVAL OF EXTERNAL FACTOR WHICH CAUSED THE VESSEL TO HEEL AT AN ANGLE IT GIVES THE STABILITY INFORMATION OF A VESSEL UNDER THE CONDITION THAT THE OUTSIDE WATER IS STATIC.

DYNAMIC STABILITY

• THE DYNAMIC STABILITY WITHIN ITS STATIC STABILITY CURVE ITS GIVES US MAGNITUDE OF EXTERNAL HEELING ENERGY THAT THE SHIP CAN ABSORB BEFORE CAPSIZING . THIS MEANS THIS SHIP CAN NOW ABSORB LESS EXTERNAL ENERGY (WIND WAVES CENTRIFUGAL FORCE DUE TO HIGH SPEED  TURNS) BEFORE CAPSIZING.

LEL ( LOWER EXPLOSIVE LIMIT)

•  IT DISPLAYED AS A PERCENTAGE WITH 0% SHOWING A COMBUSTIBLE GAS FREE ATMOSPHERE AND 100% WHEN A GAS IS AT ITS LOWER FLAMMABLE LIMIT. THE PERCENTAGE WILL DIFFER FROM GAS TO GAS.

UFL (UPPER FLAMMABLE LIMIT)

• THE CONCENTRATION OF A HYDROCARBON GAS IN AIE ABOVE WHICH THERE IS INSUFFICIENT AMOUNT OF OXYGEN TO SUPPORT AND PROPAGATE COMBUSTION, SOMETIMES REFERRED UPPER EXPLOSIVE LIMIT.

FLOODING IN ENGINE ROOM

 Flooding in engine room what will you do 

• Inform the bridge and C/E
• Rise the Engine Room alarm 
• Before starting the bilge pump note down the position of the ship. And time & date 
• Inbetween find the location of hole and repair it.
• Start the bilge pump 
• If water is too high start the another pump also.
• If water is too high,
• Protect the motors from short circuit,
• Reduce the engine rpm.
• And open emergency  bilge suction.
• If situation not under control.
• Prepare life boat for lowering.

Centrifugal Pump and Priming

Centrifugal Pump & Priming

Centrifugal pump is a radial flow pump which works on the roto-dynamic principle. It's a low pressure pump. The rotating component is impeller which imparts rotational energy to the liquid. Volute casing converts this energy into pressure energy. Discharge pressure is increased by fitting a diffuser. It is useful in a system where a high volume liquid flow is needed. 

Unlike positive displacement pump, it is not self priming pump. To remove air from the suction pipe and allow liquid to flow into the pump a water ring primer is coupled to the pump. 

Scavenge Fire

In a scavenge air space there is a normal accumulation of carbonized cylinder oil, unburnt fuel and carbon from the residual products of combustion. They will ignite under certain faulty operating conditions (such as flame blow by) indicating a fire in the enclosed scavenge air box is scavenge fire.

Causes

1. Blow past of combustion products.
2. Overheated piston throw away heat to the under piston area.
3. Blow back of exhaust gases.
4. Presence of fuel oil in the scavenge spaces.
5. Excessive cylinder lubrication. 

Indications 

1. Scavenge temperature will start increasing.
2. Turbochargers will start surging.
3. High exhaust temperature.
4.  engine lose its power and reduction in engine rpm.
5. smoke or sparks coming out from scavenge drains.
6.  will be forming of Paint blisters on the scavenge doors.

In case of Large fire - 

• Peeling or Blistering of paint.
• large reduction in engine rpm. 
• surging of turbocharger.

Actions to be taken

For small fires

1. Start reducing the engine rpm and reduce it to slow or dead slow.
2. Increase the cylinder lubrication of the affected unit. additional attention to be given for this as this does not feed the fire. In case of increase of fire should not increase the lubrication.
3. The fire may be due to leaky fuel valves, so lift up the pump of the affected unit.
4. Keep scavenge drain closed.
5. Keep monitoring the scavenge and exhaust temperatures and let the fire starve and wait for it burn itself out.
6. After confirming that the fire is out, start increasing the rpm slowly.
7. Keep monitoring the scavenge temperature for any sign of re-ignition.

For large fires

1. Immediately inform Chief Engineer and Officer on watch Bridge. Then start standby Generator. Slowly start reducing the Main Engine rpm to slow ahead, if same is not reduced automatically.
2. usually fire should extinguish on its own within 10-15 minutes.
3. If the fire does not extinguish, stop the engine and switch off auxiliary blowers. Engage turning gear and keep rotating with turning gear.
4. Stop F.O & L.O supply pumps after ensuring main engine relevant temperatures has already reduced acceptable level.
5. Open main steam inlet valve located near air cooler of main engine. open smothering steam valve and close drain valve in order to supply steam in the scavenge air receiver.
6. should not open the scavenge air box or crankcase door before the site of fire is cooled down.
7. Before re-starting main engine, should clean the scavenge space, investigate and rectify the cause.

Inspection after scavenge fire

1. Piston alignment should be checked.
2. Check piston rings and liner for any distortion. 
3. Check spring on scavenge space relief device.
4. Piston rod packing spring also should be checked.
5. Check diaphragm and frame near affected part.
6. Check guides and guide shoes.
7. Check tension of tie-bolts.

Prevention of scavenge fire

1. Clean scavenge space and drain at regular intervals.
2. Keep scavenge space drain open.
3. Excess lubrication must be avoided.
4. Piston rings must be properly maintained and lubricated adequately.
5. must be maintained Piston rod stuffing box  to prevent oil ingress in the scavenge space.
6. Cylinder liner wear must be within the admissible limits.

Scavenge space protection devices

1. Electrical temperature sensing device which will automatically sound an alarm in the event of excessive rise in local temperature.
2. Pressure relief valves consisting of self closing spring loaded valves are fitted. 
3. Fixed fire extinguishing system. (CO2 , Dry powder or Steam)

TYPES OF FLOOR

 FLOORS 

TYPES OF FLOOR 

• SOLID FLOOR
• PLATE FLOOR 
• BRACKET FLOOR

SOLID FLOOR

Its consists of solid plate with no lighting holes. It used to subdivide the area into two different tanks ..

Plate floor 

Plate floors are reverse and does have lighting holes cut into the plate, so height will reduced 

Its also reduce the strengthening of floor.

Plate floors are used to inside the tank to give additional strength while allowing fuel stored in the tank freely flow back and forth.

BRACKET FLOOR

A bracket floor lighter than all floors 

HATCH COVER / CARGO HOLD/ TESTING OF HATCH COVERS

HATCH COVERS

Cargo holds are fitted with hatch cover to avoid the cargo contact with outside atmosphere 
To avoid cargo getting wet
To avoid ingress of water in cargo hold which will danger to stability.
Its usually provided one hatch per hold
if ship having large hold, two hatches per hold

MAINTANCE OF CARGO HOLD

• Check the packing
• examine hatch beam for corrosion 
• examine for wire and rollers
• examine for broken or missing gaskets 
• examine for all moving parts 

TESTING OF HATCH COVERS

• HOSE WATER TEST

• ULTRASONIC TEST

• CHALK TEST