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PASGT LECTURE (FINAL EXAM)

What is the purpose of the Air control unit in a stern tube?

To minimize the friction

To help sealing the oil from forward and af

To help building up pressure for the lubricating oil

To provide efficient sealing in the stern tube

A type of cavitation that takes the form of a thin stationary sheet usually connecting at the leading edge of the blades.

Cloud cavitation

Mist cavitation

Sheet cavitation

Bubble cavitation

It seals the area between the stern tube and the propeller shaf

Stern glands

Labyrinth gland

Lip seal

Packing gland

It occurs when dissimilar metals are in contact in the presence of an electrolyte, such as water (moisture) containing very small amounts of acid.

Galvanic corrosion

Corrosion

Localized corrosion

Electrolytic corrosion

Controllable Pitch Marine Propulsion systems offer a wide range of advantages. Except for.

Flexibility

Durability

Economy

Maneuverability

In case of fire in the scavenge space, What is the best procedure to follow on board the ship?

Immediately start reducing the RPM of the engine

Immediately extinguish the scavenge fire

Master all the crew

Follow the company procedures regarding scavenge fire

It is best practice to check all the parameters of a Gas Turbine before starting to prevent.

Abnormalities

Breakdown of the machineries

Mis-firing of the turbine fire

Fire

A pedestal used to provide support for a rotating shaft with the help of compatible bearings & various accessories. Housing materials is typically made of cast iron or cast steel.

Plummer Block

Tilting Pad

Thrust Block

Sealing Bearing

What is the purpose alarm system on board the ship?

To bring a malfunction to the attention of operators and maintenance personnel

To prevent future accident on board

To notify the engine crew for emergency situation in the engine room

To rectify the fault

The crankcase door relief valve is consisting of ____.

Spring Plate Valve

Spring loaded Valve

Spring Valve

Leaf Spring

It is the most common types of Propellers.

Cleaver

Weedles

Conventional

Three Blade Propeller

It is the formation of distinctive bubbles cavities in the propeller.

Mist Cavitation

Cloud Cavitation

Lanmar Cavitation

Bubble Cavitation

A device that consists of a central hub with radiating blades placed and twisted so that each forms part of a helical surface and that is used to propel a vehicle (as a ship or airplane).

Propeller

Rotor

Fan

Blades

A protection barrier for propeller shafts shielding them against line entanglement around main shafts.

Rope guards

Shaft protectors

Propeller covers

Main shaft guards

It is used to support & seal the propeller shaft as it passes through the aft hull.

Stern tube

Aft pipe

Propeller sleeve

Hull seal

L.O. for Stern tube Bush is supplied by the?

Gravity tank

Oil pump

Lubrication system

Engine room

As for the height of the Gravity tank, it is installed at a place that is approximately _______ higher than the Full load draft line by factoring in the balance between oil pressure and the sea water pressure pertaining to the ship stern side’s seal..

3 - 4 meters

1 meter

5 meters

2.5 meters

The length of bearings lined with white metal or other antifriction metal.

Oil lubricated aft bearings of antifriction metal

Bearings lined with rubber or plastic.

Bearings lined with ceramic or glass.

Bearings lined with steel or iron.

For bearings of synthetic rubber, reinforced resin or plastics material?

Oil lubricated aft bearings of synthetic rubber, reinforced resin or plastics material

Metal alloy bearings

Wooden bearings

Glass bearings

It is water lubricated aft bearing where the bearing comprises staves of wood known as?

Lignum vitae

Rubber

Bronze

Plastic

The stern tube bearing consists of ___________ to prevent ingress of water and to avoid the lubricating oil to escape into the sea.

Sealing arrangement

Rubber gaskets

Metal plates

Nylon washers

Consisting of packing material around shaft liner.

Stuffing boxes

Lip seals

Radial face seal

Gasket rings

Supported with springs fitted radially around the shaft liner, aft bulkheads and after end of the stern tube.

Stuffing boxes

Lip seals

Radial face seal

Gasket rings

In contact with shaft to prevent passage of oil or water along the shaft liner.

Stuffing boxes

Lip seals

Radial face seal

Gasket rings

This forward seal has been designed to provide inboard sealing of propeller shafts with water lubricated bearings.

Mechanical seal

Oil lubricated bearing

Shaft coupling

Thrust bearing

A shaft that carries a screw/propeller at its end and transmits power from engine to propeller

Propeller shaft

Engine rod

Power spindle

Propulsion axle

This method uses a micro alignment telescope which generates a sight line between an illuminated reflective target at one end of the shafting and the telescope mounted at the other end.

Optical sight lines method

Laser alignment method

Infrared sighting technique

Ultrasonic alignment process

Similar to optical arrangement except that a laser housing generates a collimated red laser beam above the shaft which is detected by a centering detector at the other end of the shafting

Laser system

Infrared sighting technique

Ultrasonic alignment process

Optical sight lines method

Top cover off and horizontal alignment checked by measuring the side clearances of the shaft within the bearings.

Laser system

Bearing load method

Ultrasonic alignment process

Optical sight lines method

Consists of steel wire anchored above shaft at one end of system and led over a pulley with suspended weight at the other end.

Taut wire method (pilgrims wire)

Nylon rope method

Bungee cord method

Fishing line method

The shaft supported in a bearing, as it rotates, carry oil to its underside and develop a film of pressure.

Stern tube bearings

Aft seal

Forward seal

Tail shaft

The intermediate shafting if supported in plain or tilting pad bearings, has an after most bearing which is lined top and bottom. Roller bearings are installed in many vessels

Shaft bearing

Tail shaft

Journal bearing

Intermediate bearing

Based on those developed by Mitchell for thrust blocks are used for the purpose. Each pad tilts as oil is delivered to it so that a wedge or oil is formed. The three pressure wedges give a larger total support area than that obtained with a plain bearing

Tilting pads

Plummer block

Thrust block

Sealing bearing

The tilt of the pads automatically adjusts to suit load, speed and oil viscosity. The wedge of oil gives a greater separation between shaft and bearing than does the oil film in a plain journal

Tilting pads

Plummer block

Thrust block

Sealing bearing

Rotating inner ring is in two halves with a scarf or diagonal joint so that the tendency of the joint to open due to the weight of the shaft is reduced when the joint is at bottom centre

Inner ring

Outer ring

Cover ring

Wedding ring

Are in a matched pair with a diagonal split?

Cage and rollers

Pedestal cap

Split cartridge

Clamping ring

Clamps the split cartridge. The joint is spherical allowing up to 2 1/2' of swivel without effect.

Cage and rollers

Pedestal cap

Split cartridge

Clamping ring

Is located by dowels and holds the outer ring in position. Radial socket screw attach the outer ring securely to the split cartridge.

Cage and rollers

Pedestal cap

Split cartridge

Clamping ring

This rotating ring secures the split inner ring assembly and is joined by socket head screws .

Cage and rollers

Pedestal cap

Split cartridge

Clamping ring

Offer a relatively high frictional resistance to rolling but are cheap and not subject to brine ling or corrosion

Plain white bearings

Roller bearing

Coupling bolts

Thrust block

Expensive but offer little resistance to rolling. Susceptible to brinelling when stationary. The above design removes the major disadvantage of assembling the bearing onto the shaft which would normally require shaft removal.

Plain white bearings

Roller bearing

Coupling bolts

Thrust block

The purpose of a _______ on a large marine engine is to transmit the torque produced by the rotating propeller through the housing hold-down bolts into the ship’s structure

Thrust block

Tilting pad

Plummer block

Sealing bearing

consists of a housing which contains a number of wedge-shaped white metal pads with generous helical oil grooves cut into them. The pads are arranged and fixed around a steel support, holding them against a machined collar on the propeller shaft.

Thrust block

Tilting pad

Plummer block

Sealing bearing

The ___________ is also known as the "Tilting Pad Bearing" or often the "Michell Bearing" after its inventor Anthony Michell, an Australian mining engineer. The structure under the thrust block is reinforced with steel plates and I-beams above and inside the double bottom tanks or cofferdams.

Thrust block

Tilting pad

Plummer block

Sealing bearing

Are tightened to force the faces of the flange together so the friction between the faces will provide some proportion of the drive. However, fitted bolt shanks are also designed to take a proportion of the drive.

Shaft coupling bolts

Flexible hose

Propeller bolts

Thrust block

a part of the propulsion system of the ship, needs a power source to rotate A marine diesel engine located inside the ship supplies the power to the propeller. Both the diesel engine and propeller are very heavy: locating them both at the same place inside the ship would disturb the ship’s stability. It is for this reason a stern tube along with a propeller shaft is used.

Propeller

Rudder

Fan

Bow thruster

This type of propeller is used in spite of its low efficiency due to the smooth and easy maneuverability it provides, especially when the ship has to often move in the confined waters.

Controllable pitch propeller

Fixed pitch propeller

Conventional

Three blade propeller

This propeller is also used when the ship has to continuously operate at one speed or for fuel efficiency reasons where the ship has to move of different speeds and displacement.

Controllable pitch propeller

Fixed pitch propeller

Conventional

Three blade propeller

Rotates clockwise when propelling a vessel forward, as viewed from the stern of the ship.

Right handed propeller

Left handed propeller

Three blade propeller

Four blade propeller

These types of propellers are generally used for low power vessels. They are highly found in yachts or smaller vessels, as there are higher chances of facing mechanical errors when they are used in heavy and high powered vessels. An interesting point is that the open water efficiency obtained at astern is same as that at ahead

Right handed propeller

Self pitching propeller

Three blade propeller

Four blade propeller

Rotates counter-clockwise, as viewed from the stern, when in a forward propulsion mode

Right handed propeller

Left handed propeller

Three blade propeller

Four blade propeller

Suction Side of the blade facing away from you while viewing from the vessel’s stern

Blade face

Blade back

Leading edge

Trailing edge

Pressure/Pitch Side of the blade facing toward you while viewing from the vessel’s stern

Blade face

Blade back

Leading edge

Trailing edge

The edge of the propeller adjacent to the aft end of the hub. When viewing the propeller from astern, this edge is closest. The trailing edge retreats from the flow when providing forward thrust.

Blade face

Blade back

Leading edge

Trailing edge

The edge of the propeller blade adjacent to the forward end of the hub. The leading edge leads into the flow when providing forward thrust. Edge of the blade that first cuts the water.

Blade face

Blade back

Leading edge

Trailing edge

Is the degree that the blades slant forward or backwards in relation to the hub. Rake can affect the flow of water through the propeller.

Rake

Conventional

Leading edge

Trailing edge

Helps to trim the bow of the boat upward, which often results in less wetted surface area and therefore higher top end speed.

Aft rake

Forward or negative rake

Skew

Aft skew

helps hold the bow of the boat down. This is more common in workboat type applications.

Aft rake

Forward or negative rake

Skew

Aft skew

The transverse sweeping of a blade such that when viewing the blades from fore or aft shows an asymmetrical shape.

Aft rake

Forward or negative rake

Skew

Aft skew

Positive skew. Blade sweep in the direction opposite of rotation.

Aft rake

Forward or negative rake

Skew

Aft skew

Negative skew. Blade sweep in the same direction as rotation.

Aft rake

Forward skew

Skew

Aft skew

Propellers are recommended when optimal efficiency, reliability, and robustness is required.

Fixed pitch

Controllable pitch

Three blade propeller

Conventional

Offer excellent efficiency and maneuverability, and are recommended for ships requiring frequent port calls.

Fixed pitch

Controllable pitch

Three blade propeller

Conventional

A phenomena of water vaporizing or "boiling" due to the extreme reduction of pressure on the back of the propeller blade. Many propellers partially cavitate during normal operation, but excessive cavitation can result in physical damage to the propeller's blade surface due to the collapse of microscopic bubbles on the blade.

Cavitation

Water evaporation

Extreme pressure reduction

Blade erosion

Is an arrangement by which an input speed can be lowered for a requirement of slower output speed, with same or more output torque.

Reduction gear

Speed converter

Torque amplifier

Output multiplier

This arrangement consists of only one pair of gears. The reduction gear box consists of ports through which the propeller shaft and engine shaft enters the assembly.

Single reducing gear

Double reducing gear

Tripple reducing gear

Maniac reducing gear

Different gears are arranged in a cyclic manner instead of the linear manner. This arrangement is also known as epicyclic gear train. The sun and planet gear train is constructed using a big gear at center (sun) and few small surrounding gears (planet) typically.

Single reducing gear

Double reducing gear

Tripple reducing gear

Epicyclic gear

Are generally used in applications involving very high speeds. In this arrangement the pinion is connected to the input shaft using a flexible coupling.

Single reducing gear

Double reducing gear

Tripple reducing gear

Maniac reducing gear

Couplings are normally used in areas where the coaxiallity between the connecting shafts is not always assured and in areas where there is a possibility of occurrence of shocks in the transmission is applicable. They are also called as Elastic Couplings. By construction these couplings tend to have a elastic member in between the two connecting entities.

Rigid couplings

Flexible or Compensating couplings

Clutches to are a type of coupling

Reducing gear

Are equipment drive assemblies that contain hydraulically or pneumatically actuated components for connecting two shafts so that they can either be locked together and spin at the same speed, or decoupled and spin at different speeds.

Rigid couplings

Flexible or Compensating couplings

Clutches

Reducing gear

N certain conditions, sheet cavitation breaks down behind the blade into a form known

Mist or cloud cavitation

Sheet cavitation

Bubble cavitation

Vortex cavitation

Has the appearance of a stranded twisted rope and can be present at either the blade tips or the boss.

Mist or cloud cavitation

Sheet cavitation

Bubble cavitation

Vortex cavitation

Effects of cavitation, except?

Reduced performance

Blade erosion

Vibration

Corrosion

Are critical components of ships and boats, and their safe operation is paramount to ensure the safety of the crew, passengers, and vessels.

Marine diesel engines

Faulty navigation systems

Inadequate life-saving equipment

Poor maintenance of hull and propellers

Lack of proper training for crew members

Is to ensure safe and reliable operation of the engine and to protect the Marine engines from potential hazards.

Safety device

Alarm

Gauge

Valve

Are designed to detect and alert Marine engineers to potential issues before they can cause serious damage to the engine or compromise the safety of the vessel.

Safety device

Alarm

Gauge

Valve

Protect large diesel, gas, and dual-fuel engines of all applications. They protect against heavy consequential damage due to oil mist explosions, a result of overheating of bearings or moving parts?

Oil mist detectors

Crankcase relief doors

Scavenge relief valve

Relief valve for starting air

Are also fitted to prevent any damage to the crankcase and ingress of fresh air inside the crankcase.

Oil mist detectors

Crankcase relief doors

Scavenge relief valve

Relief valve for starting air

Is a safety valve used in marine diesel engines to prevent excessive pressure buildup in the scavenge air system.

Oil mist detectors

Crankcase relief doors

Scavenge relief valve

Relief valve for starting air

Designed to open when the scavenge air pressure exceeds the maximum allowable limit, allowing excess air to escape and maintain the pressure within safe limits.

Oil mist detectors

Crankcase relief doors

Scavenge relief valve

Relief valve for starting air

Is designed to open when the starting air pressure exceeds the maximum allowable limit, allowing excess air to escape and maintain the pressure within safe limits

Oil mist detectors

Crankcase relief doors

Scavenge relief valve

Relief valve for starting air

Is a safety valve used in marine diesel engines to prevent excessive pressure buildup in the starting air system.

Oil mist detectors

Crankcase relief doors

Scavenge relief valve

Relief valve for starting air

Is responsible for removing exhaust gases from the engine’s cylinders and delivering fresh air to the cylinders for combustion.

Oil mist detectors

Crankcase relief doors

Scavenge air system

Relief valve for starting air

Typically located in the starting air line and is spring-loaded to remain closed until the starting air pressure exceeds the set limit.

Oil mist detectors

Crankcase relief doors

Scavenge air system

Relief valve

Safety device used in marine diesel engines to prevent the propagation of fire or explosion from the engine’s starting air system to the surrounding environment.

Oil mist detectors

Crankcase relief doors

Starting airline flame trap

Relief valve

Typically located at the inlet of the starting air system and is designed to prevent any flames or sparks generated within the starting air system from escaping to the surrounding environment.

Oil mist detectors

Crankcase relief doors

Starting airline flame trap

Relief valve

Designed to relieve pressures in excess of 10% to 20% above normal.

Oil mist detectors

Crankcase relief doors

Starting airline flame trap

Cylinder relief valve

Is an essential safety feature in marine diesel engines, as it helps to prevent the propagation of fire or explosion and ensures safe and reliable operation.

Oil mist detectors

Crankcase relief doors

Starting airline flame trap

Relief valve

A typical Alarm System will have a sensing device such as, except?

A level sensor

Thermocouple

Pressure sensor

Relief Valve

Device will cut off the fuel supply in the speeding Engine event more than the predetermined value.

Over speed trip

Jacket water high temperature alarma and trip

L.O. low-pressure trip, alarm and trip

High exhaust gas temperature

Removes the waste heat. Failure of jacket water to remove the heat away, seizure of the components will take place due to expansion.

Over speed trip

Jacket water high temperature alarma and trip

L.O. low-pressure trip, alarm and trip

High exhaust gas temperature

Are too critical and can provide information regarding the Engine operation.

Over speed trip

Jacket water high temperature alarma and trip

L.O. low-pressure trip, alarm and trip

High exhaust gas temperature

Is to create a series of barriers that gradually reduce pressure such that the final seal is not subject to a large volume of sealing media at these higher pressures

Labyrinth seals

Mechanical seals

Packing seals

Carbon seals

The common issues with the above labyrinth seals of failure due to friction has been solved by the?

Labyrinth seals

Mechanical seals

Packing seals

Carbon seals

Help determine the areas of the lowest friction and help engineers choose face materials and design seal cross sections.

Labyrinth seals

Stribek curves

Packing seals

Carbon seals

This method can also cause damage to the shafting itself as it is always in contact with rotating equipment and can begin to breakdown the materials and cause galling and pitting as sealing media beings to corrode the rotating shaft.

Labyrinth seals

Stribek curves

Packing seals

Carbon seals

The oldest and most utilized system of sealing of rotating equipment is through the use of packing.

Labyrinth seals

Stribek curves

Packing seals

Carbon seals

PAPASA KA KAYA?

HINDI

MEDYO

EWAN

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