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Auxiliary Machinery Part 2 - Coggle Diagram

- - - - Centrifugal clutch
        
        It is mainly used to operate purifiers and air motors
      - Dog clutch
        
        It is mainly used to operate deck hydraulic winches.
      - Multiple plates/Discs clutch
        
        It is mainly used to operate the Main Propulsion
        Reduction gearbox.
      - Slip clutch
        
        It is mainly used to operate the latest marine propulsion reduction gearbox technology.
  - - - Single Helix
      - Double Helix
      - Spur Gear
      - Epicyclic Gear (Planetary Gear)
    - - It is the ratio between the circumference of driven gear and the circumference of pinion gear.
  - - - Run auxiliary outputs from single input
      - Convert multiple inputs to single output
- - - - The thrust shaft rests on thrust block bearings.
      - The thrust collar is part of the thrust shaft and acts
        on the thrust block (more details in next chapter).
    - - One or more numbers, depending on the position of the main engine, relative to the propeller
      - Coupling bolts pass through each flange, securing the adjacent flange with nuts
      - Each end of shaft usually consists of a flange
      - Coupling bolts (and friction between the flanges) transmit the TORQUE
      - Intermediate Bearing provided with bearing surface in the
        bottom half only.
      - A Plummer Block Bearing (a slightly larger Intermediate Bearing with top & bottom bearing surfaces) may be used to support the aft-most section of the shaft.
      - Intermediate Shaft/s: supported by Intermediate Bearing, aka as tunnel bearings
    - - Components
        
        Aft end coupled to thrust shaft with thrust collar
        
        Rest on the main bearings (inside engine casing)
        
        Detuner (provided at forward end of engine):
        To counter critical torsional vibration
      - Types
        
        Semi build type : Web & crankpins fabricated as one unit &
        shrunk onto the journals.
        
        One piece crankshaft : Usually drop forged as single piece.
        Normally used for high speed engines
        
        Fully build type : All 3 parts are fabricated separately &
        webs shrunk on the crankpins & journals.
    - - Shaft goes through a sterntube (cast iron), fitted at the lower part of the after peak tank
      - Shaft is supported by sterntube bearings or bushes at ends of the tube
        
        White metal bearing : Oil lubricated
        
        Bronze bushes lined with lignum vitae (wood) : Water lubricated
      - Carries the propeller at the aft end
      - Stern gland
        
        Keeps sea water out of engine room
        
        Keeps lubricating oil within the stern tube
    - - Crankshaft
        
        Forces from connecting rod
        
        Forces on the main bearings
        
        Torsional Vibrations
        In propulsion with 2-stroke (slow-speed)
        diesel engines, propeller is usually directly
        driven, i.e., engine & propeller run at the
        same speed.
        Changes in cyclical forces of diesel engine
        (due to different loads and speeds) creates
        torsional vibrations.
      - Intermediate Shaft
        
        Compressive stress (due to ahead movement)
        
        Torsional stress (due to rotation)
        
        Bending stress (due to hogging and sagging of hull)
        
        Tensile stress (due to astern movement)
      - Tailshaft / Propeller Shaft
        
        Bending stress (due to weight of propeller)
        
        Compressive & Tensile stresses (due to alternating thrust
        forces by the propeller)
        
        Torsional stress (due to rotation)
      - Shaft alignment
        
        Methods for shaft alignment checks
        
        Micrometer
        
        Feelers between coupling faces
        
        Piano Wire
        
        Optical method
        
        Laser method
  - - - Semi-permanent or removable coupling
        
        • Shaft is a straight piece at the ends
        • A flange with a boss is separately forged
        • Boss is machined for shrink fitting onto the shaft
        • Bearings are roller type
      - Muff coupling
        
        Couplings placed in position.
        
        HP injectors connected to A.
        
        LP pump connected to B.
        
        HP oil injected into A, oil film built
        up between inner & outer sleeve.
        
        Oil leaks out through the thick end
        of the inner sleeve.
        
        Oil is pumped into B & the outer
        sleeve starts moving towards the
        left side.
        
        Oil is continuously fed through A to
        avoid metallic contact of the sleeves.
        
        Once distance C is obtained,
        pressure in A is released.
        
        Pressure at B is released when oil has
        drained off from contact surfaces of both the
        sleeves.
        
        All connections are then plugged
      - Fixed flange coupling
        
        Flanges are integral with shaft
        length
        • Holes are drilled & reamed to
        take the fitted bolts
        • Bolt shaft and the holes may be
        parallel or slightly tapered to
        improve fit contact
        • Flanges are brought together
        and bolted
    - - Parallel Shank Bolts
        
        • Shank are parallel & cylindrical
        • Slight taper at the forward end
        for easy entry
        • Bolt head is cylindrical or
        hexagonal & nut is hexagonal
      - Small Taper Bolts
        
        • Small taper in the shank region ,1 in 100
        • Flange holes are reamed to the same taper
        • Small clearance between bolt head & face of the flange
        • Clearance taken up with tightening of the nut
      - Taper bolts (Large taper bolts)
        
        • Taper of about 6 in 100
        • Do not have bolt heads
        • Fitted accurately to reamed holes
        • Tightened with hammer & spanner