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Valve Hysteresis 

It is an undesireable characteristic which affect valve positioning. 

Effect is the actuator pressure does not produce the same valve opening

Causes 

1) non linearity in actuator force due to varing effective diaphragm area 

2) non linearity in valve opening force due to varying opening rate 

3) non…[Read more]

1)Akin to the ‘Black Box’ on airplanes, a Voyage Data Recorder is an equipment fitted onboard ships that record the various data on a ship which can be used for reconstruction of the voyage details and vital information during an accident investigation.

Information is stored in a secure and retrievable form, relating to the position, move…[Read more]

1. Loss of Oil from Crankcase

– Operational leakage

– Foaming

– Suction pressure drops rapidly from evaporator

– Compressor running on high capacity (unloading setting)

Action

– Use defoaming agent during prolong shut down

– Shut stop valve in liquid supply line to expansion valve

– Suction and discharge valves to shut…[Read more]

To fully prevent oil leakage. #3s added as spare ring

In case of leakage, #3s seal ring is put into operation by close the line valve for #3, #3s will activate

In case of all seal failure,

1. Adjust LO pressure of stern tube to equal or higher then sea water pressure by changing the gravity tank position. If seawater leaking in
2. If…

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Sacrificial Anodic Protection

1. Sacrificial anodes work on the principle of electrolysis,
2. an anode and a metallic strip are dipped in electrolytic solution, 
3. Anode electron will dissolve and deposit over the metallic strip and make it a cathode.
4. Seawater acts as an electrolyte and transfers the electrons from the anode to the steel…

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 Reasons taking too long to fill up. 

• Unloader leaking
• Bottle drain valve or relief valve leaking
• Air consumption increase due to some valve kept open, someone using air continuously, air leakage on pipe/ flange.

factors affecting volumetric efficiency,

• bumping clearance increase
• suction & discharge valves sticky, leaky

…

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Possible causes:

1. 1. 1. 1. Flame eye dirty 
         2. Pilot burner. ( DO tank empty, do pump not working, nozzle choked, igniter electrode>  no voltage, position wrong, fouled or gap too much)
         3. Air/ fuel ratio incorrect
         4. Air fuel ratio adjusting linkage incorrect
         5. ACC failure

Main burner 

1. Valve shut 
2. Filter cho…

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Turn down ratio indicates the flexibility of burner to cope with different loads without losing efficiency.

TRD = fuel consumption at max load/ fuel consumption at minimum load.

Pressure jet burner TDR 3:1

Rotary cup TDR 15:1

Steam blast TDR 20:1

Ultrasonic  TDR 15:1 

• Simple pressure jet burner

Atomization of f…[Read more]

1. Combustion control system correct the proportion the quantities of air and fuel being burnt. 
2. Ensure complete combustion
3. The system measure the flow rates of fuel oil and air in order to correctly regulate their proportions.
4. Two control elements are used, ‘steam flow’ and ‘steam pressure’. 
5. The steam pressure signal is fed to a c…

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Difference between a safety valve and a relief valve

• Relief valve:

The higher the pressure, the more the valve disc lifts off its seat. Relieving capacity increases with over-pressurization increase.  

• Safety valve:

Designed to stay completely closed until the popping pressure is reached. At popping point the valve lifts sharply a…[Read more]

Fitting of new tie rod 

1. The lower nut of tie rod is screwed on 
2. Clean the seating surface of intermediate ring and upper nut 
3. Screw ring screw on tie rod and lift till the lower tie rod rest against the bearing shield 
4. Tighten the upper tie rod nut with tommy bar until seated firmly, then remove ring screw

Tightening Seq…[Read more]

Solas Requirement for UMS

SOLAS 1974 Chapter II-1, regulations 46 to regulation 53. 

1) Protection against fire 

a)     Arrangement should be provided on UMS ship to detect and give alarm in case of fire.

b)      In the boiler air supply casing and uptake.

c)      In scavenge space of propulsion machinery.…[Read more]

Load line survey

In order detecting whether the vessel is over-loaded and it’s freeboard,

it is basically an effort to make the hull watertight below the freeboard and weather tight above it.

It is a administration requirement for ships to get Load line certificate which is subjected to annual survey.

• 150 GRT and above
• New sh…

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Solas emergency power supply requirements

1. Emergency generator and emergency switchboard of the ship should be located above the uppermost continuous deck, away from machinery space, behind the collision bulkhead.
2. The main switchboard of the ship should not interface with supply, control, and distribution of emergency power.

…

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https://www.youtube.com/watch?v=HGY6EYjO4Y0

Marpol stands for International convention for the prevention of pollution.
73 convention/ 78 protocol. 1973 as modified by the Protocol of 1978, Came to force on 1983.

convention; an agreement between states covering particular matters
protocol; is a draft of official document signed by…[Read more]

Seatime required

From Cadetship to COC 5 : 6 months
From COC 5 to 2 : 12 months ( MEO CLASS 1 & 2 Engineering co
COC 2 to COC 1 : 18 months ; COC 5 to COC 1

Enrolling for COC 1/2 Marine engineer Part B course, Studends exempted from Part A if we graduated from…[Read more]

Checklist and past questions here!