The universally accepted and essential focus area for today’s shipping industry is efficiency. It represents a critical element of a vessel’s operating costs, which in turn have a direct impact on profitability. At the same time, efficiency is being regulated by the International Maritime Organisation (IMO) through its Energy Efficiency Design Index. This means that the design of new vessels has to meet ever more stringent efficiency requirements.
Today’s vessel designs increasingly utilise shorter shaft lines with the engine(s) located further aft, therefore allowing the hull to accommodate additional cargo. However, this can open the door to a new set of problems. With heavier and more efficient propellers now being used, the shorter shaft line has a greater tendency to bend, which not only negatively affects the alignment, but can cause serious damage to the rest of the shaft line equipment. Furthermore, ships are often running at slower speeds to save fuel, which creates a higher friction coefficient on the wearing parts and, therefore, a greater possibility of faults occurring.
While efficiency is being highlighted for all aspects of a ship’s operations, tail shaft alignment is seldom at the top of the priority list. Nevertheless, it is important for eliminating the vibration and unnecessary frictional losses that can create considerable inefficiencies. Wasted energy not being converted into thrust diminishes performance and harms the overall efficiency of the ship.
Measurement of the tail shaft can reveal if alignment is needed. If misalignment has occurred, repairs are necessary both to retain operational efficiency, and to prevent the possibility of costly damage being caused to the propulsion equipment by the misalignment.
Modern, condition-based monitoring (CBM) can provide an accurate insight into the state of the tail shaft. In contrast to static alignment checks, CBM can dynamically detect faulty alignment and determine precisely how the equipment is performing when in use. It will deliver detailed root cause information on vibration levels, temperature, runout, whirling, movement, torque, stress, and on the position of the equipment.
The latest tools and technology can also be used to provide fast and accurate measurement to detect any vertical or horizontal misalignment. Whether the measurement service is for a modern vessel with a shorter shaft, or for an older ship with a more traditional length of shaft, full alignment is essential for efficient operation.
Wärtsilä Seals & Bearings offers all of the above services plus repairs if and when needed. Monitoring is carried out using a portable CBM (PCBM), which enables the measurements to be carried out even while the vessel is underway. With this level of CBM service, there is no vessel downtime involved since the portable system can be mounted in a single working day and removed for data analysis when the ship is next in port. The company’s patented gyro laser alignment technology allows the necessary realignment work to be handled with a minimum of delay, which is of particular value if the vessel is operating on a tight schedule.
Wärtsilä offers a turnkey approach, representing a full-scale and highly effective means of ensuring perfect shaft line alignment. The measurements are carried out using class-approved methodology, the analysis is made by senior technical specialists in accordance with classification society requirements, the reporting procedure provides a record of the measurement and a proposal for the corrective actions, and the repairs utilise class-approved methodology and OEM engineering and parts.
“Wärtsilä Seals & Bearings has considerable experience and deep inhouse capabilities for state-of-the-art alignment services that enable optimal vessel performance. Professional alignment from a reputable company such as Wärtsilä can make a valuable contribution to the ship’s operational efficiency,” said sales manager, Seals & Bearings Alignment, Rene Bertelsen.