|Minimum Order Quantity
|Type Of Design
|Stern Tube Laser Alignment
Propulsion shaft ( Stern Tube ) alignment is a process that consists of:
• The design and analysis
• The alignment procedure
• Measurements and verification
The terminology and requirements for shafting alignment vary depending on the type of the system analyzed (propulsion, gen-set, etc.), the powertrain size, and the alignment process itself.
Propulsion Shafting Alignment:
A static condition observed at the bearings supporting the propulsion shafts. To suitably define propulsion shafting alignment, a minimum set of parameters are defined in the design stage and subsequently confirmed acceptable on board: • Bearing vertical offsets • Bearing reactions • Bearing to shaft contact condition (i.e. misalignment angles) • Crankshaft web deflections • Gear mesh misalignment.
Alignment is considered satisfactory when these parameters can be controlled in the static and dynamic condition and maintained within the required limits under all operating conditions of the vessel for all service drafts and service temperatures. A change in the vessel’s draft due to altered loading conditions affects hull girder deflections. This in turn influences bearing offsets, causing a redistribution of the load among the bearings. Achieving a satisfactory alignment design for the loading conditions included in the vessel’s loading manual requires several repeated analyses.
Most modern vessels are state of the art designs, with highly efficient propellers and high-powered main drives with low fuel consumption. Their hull structure is optimized to reduce deadweight and maximize cargo capacity. Unfortunately, most modern ship design improvements can adversely affect propulsion shafting alignment if this is not correctly addressed.
The shaft alignment analysis provides the necessary, accurate and applicable data to support each stage of the actual alignment process.
The alignment procedure is conducted with the required accuracy.
Allowable shaft alignment tolerances are measured in fractions of millimeters, while acceptable hull construction margins are measured in tens of millimeters. Ideally, a shaft alignment analysis should be performed for maximum allowable alignment tolerances, resulting in acceptable bearing reactions and misalignment angles under all operating conditions of the vessel: loaded, ballast, hot and cold. This implies that hull deflections are initially accounted for in the analysis.
- Delivery Time: 10-15 Days