Marine propulsion alignment consists of ensuring that all bearings and rotational centerlines are set into a straight line as per the installation requirements. Depending on the vessel size, this means the machine, gearbox, clutch, support bearings, stern tube and struts should all make a straight line when the vessel is at sea. Proper propulsion alignment prevents unnecessary loads to the bores and prevents vibration due to back and forth bending cycles of the propeller shaft due to misalignment.
Ensuring this alignment is correct in dry dock is a physically demanding task! Ask anyone that has been tasked to perform such measurements and they will probably have stories of climbing in and out of the stern tube and though cramped spots—“Propulsion Alignment Yoga”.
With all the components that will need to be checked and re-checked after corrections, it is imperative that the alignment system be accurate and easy to use. Traditional marine propulsion alignments involve the use of a tight-wire that is stretched down the length of the propulsion line. While simple in concept, it is not without its woes. If a component needs to be removed, the line must be broken and reset. The wire can bounce due to wind and vibration. Finally, the operator must physically avoid coming in contact with the wire. In many cases, this is physically impossible and dangerous. It is dangerous because if the user was in a stern tube taking a measurement and the line broke, that high tension wire could seriously injure the person in the stern tube!
Fortunately, this task is made both safer easier with the Easy-Laser E950B laser marine propulsion alignment system. The concept is simple: the laser beam replaces the tight wire. The high accuracy laser sensor replaces the inside micrometer. The system digitally records the position of the sensor and touch probe with respect to the laser with a high accuracy (0.02mm). The result is quick and easy measurements of marine propulsion alignment. After the alignment is finished, the system creates a report for documentation showing that any alignment defects have been eliminated.
Alignment, Geometric Measurement by Daus Studenberg CRL