- You have seen and operated several valves onboard ships. All the butterfly valve operation handles are operated by a locking arrangement because
- Butterfly valves do not used gland packings and thus spindle doesn’t have anything to keep it in position and can open by vibration
- Butterfly valve does have a spindle packing but same cannot be excessively tightened to have good grip on the spindle to prevent it from opening against vibration
- Butterfly valves can move by vibration but that is not the main consideration, the main consideration being opening/closing against liquid pressure
- All the butterfly valves do not have locking arrangement as there is no such requirement for the same
- Which of the group of method are used for priming of centrifugal pumps onboard ships?
- Gravity tank, attached vacuum pump
- Attached Vacuum pump, filling pump casing using a fresh water hose
- Central priming system, attached vacuum pump, sea water priming
- None of the above
- Which one of the following is a type of corrosion :-
- The size of solid particle contaminants in hydraulic systems is measured in:
- Millimeter cubed
- Micro millimeter
- Pump Start But Motor gets overloaded or Trip on overload.
- Alignment is wrong
- Gland packing too tight
- Worn out / Damaged ball bearing
- Cavitations exists
- All of the above
- Which of the following instruments measures propeller drop?
- Poker Gauge
- Telescopic feeler gauge
- Propeller drop gauge
- Which of the following can be done to reduce the cold corrosion of Main Engine cylinder liners using high sulphur fuel oil :-
- Increasing cylinder oil feed rate
- Using high TBN cylinder oil
- Increasing scavenge air temperature
- Decreasing cylinder oil feed rate
- Your ship has a OWS and reciprocating bilge pump of capacity 2.0 m3 /hr. It takes about 12 hours to pump out the complete bilge tank through OWS. The ship is going to dry-dock and Chief Engineer is recommending company to install a centrifugal pump of 10 m3 capacity which will take the same space and can pump out the bilge tank only in 2.5 hrs. The company should:
- Accept the proposal as a centrifugal pump has several advantages over a reciprocating pump
- There is no question of accepting a centrifugal pump as a Engine room bilge pump
- Propose to fix a Gear pump instead of a centrifugal pump
- Pipelines and pumps once designed cannot be changed as they are class approved
- Normally so called ???single screw pumps??? are used as sludge pumps in engine room. What is the correct technical name of these pumps?
- Snake Pump
- Screw Pump
- Progressive cavity pump
- Gerotor Pump
- In a Parallel-Gate type valve the sealing between the valve and the disc is provided by:
- Appropriate tightening torque of the valve spindle
- Gate and valve seat have a taper and when tightened they will seal against each other
- Either the seat or the disc Gate are free-floating, allowing upstream pressure to seal the seat and disc against any unwanted leakage
- For a gate type valve the sealing is never perfect and they always allow some leakage
- The crank web deflection readings of a diesel engine would be erroneous in which of the following conditions?
- When the draught of the vessel has changed while readings were being taken
- When cargo loading and discharging has been too rapid
- When the crankcase temperature has changed substantially during the process of taking the readings.
- None of the above
- The purpose of an evaporator in the domestic refrigeration system is to
- Transmit latent heat of evaporation
- Absorb latent heat of fusion
- Absorb latent heat of evaporation
- Transmit latent heat of fusion
- Which of the following is an important requirement for proper functioning of sacrificial anode system :-
- Good Insulation between anodes and ship???s hull
- Good electrical continuity between anodes and ship’s hull
- Providing protection of anodes from being painted over during hull painting
- Presence of an insulating material between anode and the cathode
- The main disadvantages of a reciprocating pump over a Gear pump is that:
- A gear pump is self priming while a reciprocating pump is not
- Discharge of a gear pump is not affected by the direction of rotation while that of reciprocating pump is reversed
- The discharge of reciprocating pump is pulsating and discharge rate is lesser
- Reciprocating pumps are only available in high capacities and for smaller capacities only gear pumps can be used
- Which of the following types of damages are metal seatings of a valve subject to?Choose the correct alternative.
- Corrosion, Erosion, Abrasion, Deformation
- Corrosion, Fatigue failure, brittle fracture, caustic cracking
- Erosion, caustic cracking, brittle fracture, Cloverleafing
- None of the above
- You are pumping out sludge to a shore facility using your sludge pump. You find that the discharge rate of pump is very slow and suction filter is getting clogged frequently.What is the best alternative to counteract the problem?
- Remove the pump suction filter and pump out the tank
- Increase the tank temperature, keep an eye on the pump suction pressure and clean the filter as soon as it drops
- As soon as the as the shore facility tells you that they are not receiving any sludge, you stop the pump and clean the filter
- Fabricate a bigger mesh size suction filter and use in place of normal filter so that frequency of filter blockage is reduced and you can get a better discharge rate
- When centrifugal pump is used to pump a liquid of higher specific gravity the pump Power will
- Will not be affected as the pump power depends only on the flow capacity
- None of the above
- The process of depositing zinc on steel surfaces by diffusion coating is known as :
- By which of the following is the attached vacuum pump of a ballast pump is driven?
- Electrical motor
- Hydraulic motor
- Pump driven clutch
- Pneumatically driven
- High tensile steels are :
- High carbon steels with suitably added alloying elements
- Medium carbon steels with suitably added alloying elements
- Low carbon steels with suitably added alloying elements
- None of the above
- After cleaning the sea chest filter you have placed the filter in the body and tightened the cover. Which one of the following is the best alternative?
- You can open the filter inlet and outlet valves & directly start using the filter
- If you do not want to use the sea chest in question, you need not worry and you can open the valves when required
- Sea Water inlet valve should be crack opened, the filter body should be purged, any leakages and thereafter filter can be kept isolated or used as required
- You will close the other side sea chest valves first and then open this side sea chest filter inlet and outlet valves
- Which of the following valves cannot prevent backflow of liquid in a pipeline?
- Gate valve
- Globe Check Valve
- Swing Check Valve
- Angle check valve
- Most steam traps respond well to cleaning. But when a thermodynamic trap fails to operate after cleaning, the next course of action should be:
- Throttle the steam outlet valve
- Renew the trap
- Lap the disc and the seat of the trap
- Throttle the steam inlet valve
- Which of the following option gives you the correct sequence of the metals in decreasing order of preferential corrosion when all of them are bonded and immersed in an electrolyte ?
- Titanium, Mild Steel , Zinc , Stainless steel
- Titanium , Stainless steel ,Mild Steel ,Zinc
- Zinc , Mild Steel , Stainless steel , Titanium
- Zinc , Titanium , Mild Steel , Stainless steel
- Bronze is an alloy typically consisting of :-
- Copper , lead & tin
- Copper , Zinc & lead
- Copper , Zinc & Tin
- Copper , Tin & Lead
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