Shaft Alignment

Satisfactory shaft alignment is crucial to the safe and efficient operation of any vessel. While much alignment work can be done routinely, difficulties are often encountered which demand in-depth knowledge and understanding. 
Our range of measurement and in-house-developed analysis techniques, coupled with our extensive experience, enable us to carry out tailored assessment of propulsion system alignment and investigate shaft line component failures. Shaft alignment Practical help to overcome and avoid problems 

Diagnosing faults 

Shafting weight, the overhung propeller and its associated operational loads, and the flexibility and loading of the ship’s structure, combine to make shaft alignment a far from trivial process. Establishing the alignment condition is critical and is mainly achieved through three measurement techniques; bearing jackings, strain gauge and optical alignment. 
Our strength is to combine these techniques with a rigorous approach to shaft line component measurement and observation coupled with extensive knowledge and experience. All data obtained is assimilated to develop robust and reliable solutions across the range of vessel and machinery operating conditions. Significant advantages, in terms of time and accuracy, are accrued when compared with gap and sag methods. 

Bearing jackings 

A traditional technique employed worldwide for determining a bearing’s static vertical load. To ensure maximum accuracy we use an electronic load cell and display the shaft lift/jack load characteristic on a computer as the measurement is taken. 

Optical alignment 

Use of the micro-alignment optical telescope, its associated targets and mounting equipment, enables a datum line of sight to be established rapidly, easily and, importantly, with repeatability. From this, the overall and local alignment conditions of the shaft line bearings and their respective housings are established. 

Strain gauge alignment 

A technique developed by TID, the benefits of which are: – The main engine coupling loading condition can be determined. – Identifies the vertical and transverse static bearing loads. – Permits calculation of the bearing loads at normally inaccessible, but critical, locations such as the stern-tube after and reduction gearing bearings. – Identifies the changes in shaft line deflections as a function of vessel lading condition. 

Increased confidence 

Measurements are taken throughout the repair, including repeat ones in different thermal or draught conditions which can be made within just a few hours. These ensure that the desired alignment condition has been successfully implemented and achieved. 
The merging of these practical disciplines with other analytical techniques can be combined to enhance confidence and allows a wide variety of shafting problems to be investigated and resolved. 

Impartial shafting system analysis 

Our practical and analytical techniques, knowledge and experience can also be employed in support of the design and construction phases of shipbuilding. The full range of TID’s analytical capabilities are presented in the complementary factsheet 

The benefits of shaft alignment

– Rapid diagnosis of shaft alignment problems, and reduced risk of reoccurrence. 
– Helps minimise downtime or off-hire time. 
– Provides the potential for performance improvements through proactive application of lessons learned to other vessels in your fleet. 
– Impartial service and support worldwide. 

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