The primary purpose of ______ is to transfer the torque generated by the main engine to the propellar and to transmit the thrust developed by the propeller to the thrust bearing in the ship.
Propulsion Shafting
What is shafting supported by inside the skin of the ship?
Line Shaft Bearings
A split inflatable seal installed aft of a stuffing box and gland which is designed for the alternate use of the split face type seals or conventional packing
What is the most common seal found for surface ships?
The term “shaft alignment” when used in the marine field generally involves two of the following functions:
- The first is the aligning of the bearings that support the shaft.
- The second alignment function is the alignment of the shaft flange to the output flange of the reduction gear, main motor or directly to the slow speed diesel
The major factor influencing shaft and bearing alignment is:
- Hull deflection
- Various loads and ballast conditions
- Hull speeds
- Heavy seas
What is Hull Deflection caused by?
Daily and seasoal temperature variations
- Vessel is in the water
- All permanent ballast are in place
- Fuel, water and temporary ballast tanks are filled to normal average operating levels, 1/2 to 3/4 filled
- All major machinery weighing over 1000lbs is either installed or simulated
- Make final alignment immediately prior to sea trials.
DO NOT ATTEMPT final alignment of propulsion engines/shafting unless the following conditions are met:
Refers to the distance the face of the hub is out of perpendicular to the shaft centerline.
Face runout
Refers to the distance the driving bore of the hub is out of parallel with the shaft centerline.
Bore runout
Any eccentricity or perpendicularity errors must be accounted for in the _____ process.
Alignment
The bore to pilot diameter eccentricity error should be no more than ____ inches or as specified by the manufacturer.
0.002 inches (0.05mm)
The flange face run should be no more then ____ inches or as specified by the manufacturer.
0.002 inches (0.05mm)
Move the engine and marine transmission to their approximatefinal position within ____ of the companion flange without engaging the flange pilot.
0.3 inch (8mm)
How do you check bore alignment?
Take measruements of the diameter gap at four equally spaced points on the flanges diameters, A, B, C & D
What is shafting supported by outside the skin of the ship?
Bearing located in struts, skegs and stern tubes
This procedure is concerned with eliminating shaft vibration and noise, ensuring that no bearing is overloaded and that there is no excessive stress on the shaft.
Aligning of the bearing that support the shaft
In this phase of alignment, reduction of loading on reduction gear and engine bearings is of importance.
Alignment of the shaft flange to the output flange of the reduction gear, main motor or directly to a slow-speed diesel.
An appropriate method to account for shaft droop utilizes a _______.
load ring, turnbuckle and sling
The alignment of the line shafting to the marine transmission output flange must be within specified tolerance for_______.
satisfactory transmission service life
What is the first step if a bearing alignment check and realignment procedure is needed?
Ensure that the ship is docked in as close as possible to the configuration of the hull when floating
What are two methods used to establish a new bearing line?
- Sag and gap method
- Bearing reaction readings
This method of establishing a new bearing line requires the aft coupling bolts and the shaft-to-reduction gear coupling bolts to be removed.
Sag and Gap Method
This method for establishing a new bearing line involves lifting the shaft with a hydraulic jack.
The Bearing Reaction Readings Method
What is the preferred method for establishing a shaft line?
Laser/Optical
The ___ is the part of the alignment process that aligns the shafts centerlines from side to side.
Horizontal move
The _____ is the part of the alignment process that aligns the two shafts centerlines into their proper up and down positions.
Vertical Move
For safety purposes, what should be covered prior to removing to prevent spraying or splashing or pressurized fluids?
- lubrication fittings
- plugs
Where are the bearing used to support sections of the shafting outside of the ships skin?
- Struts
- Skegs
- Stern Tube
What supports shafting on the inside of the ships skin?
Line shaft bearings
What is the purpose of the first function involved in a shaft alignment?
Align bearings and support the shaft
What can the shaft flange be aligned to during an alignment?
- output flange of reduction gear
- main motor
- slow-speed diesel
When should you NOT ATTEMPT to make final alignment of propulsion engine shafting?
When fuel, water and temporary ballast tanks are empty
