Smoothing out the bumps for workboats
Sleipner Motor’s test boat took the stabilisers to the water for two years before marketing.
Stabilizer systems have been around for a long time, but typically only used on larger vessels.
However, a range of intelligent ‘self-adjusting’ fin stabilizer systems compact enough for use on workboats was shown at the Seawork exhibition this summer.
The key benefits for the workboat market include a generally safer operation. It is less likely for crew to fall while working on deck in steep seas, and there is reduced wear and tear on a vessel because it is not necessary to head either into or away from large waves for the sake of a smoother ride.
All stabilizing systems, including fins and gyro systems will, in principle, slow the boat down and increase fuel consumption at the same speed. However this does not mean that the overall fuel economy will automatically get worse, as V-hull operators tend to ramp up the speed in order to keep rolling motion down. But given a more comfortable ride, even in bad weather, there is a saving to be had, as keeping off the throttle lessens the fuel throughput considerably. This also saves the boat from the pounding and extra stress it is subjected to at high speeds in heavy waves.
Prior to launch, these products were subjected to an exhaustive test and evaluation procedure, carried out on a purpose designed and built boat of 58ft length, with twin 800hp engines equipped with a sensor package and full logging computer for data analysis and collection.
There were some interesting findings from Sleipner’s test boat, which enabled the company to develop a system with greatly reduced water resistance on the outside and a considerably compact footprint on the inside.
One stabilizer fin is fitted to each side of the immersed hull and the two are linked together on a counter-operating principle. Unlike alternative solutions, some of which rely upon a single cylinder, Sleipner stabilisers are driven by dual cylinders, for equal strength in both directions, with more balance and less load strain on other mechanical parts.
Dual cylinders also mean the weight and size of the shaft, bearings and the actuator can be moderated accordingly, resulting in a lower profile and more compact solution which allows for convenient installation.
Made from vacuum infused vinylester, moulded over a pre-shaped core with a steel structure to secure the shaft, the fin-stabilizers themselves are extremely strong, and have been designed using advanced hydrodynamic software for low drag and high efficiency.
At the heart of the system is a controller (arguably the most important part of the package), which combines predictive algorithms with real-time sensor adjustments. Together with pressure sensors on the fins, information is passed back to a touch screen display to give the fullest possible picture to the operator.
If a Side-Power thruster and hydraulic system has already been installed, then opportunities exist to integrate the main hydraulics of the stabilizer system via Sleipner’s S-Link intelligent ‘plug and play’ system. Alternatively, installation as a completely stand alone product is perfectly achievable.
Images for this article - click to enlarge
Unless otherwise stated, all images copyright © Mercator Media 2012. This does not exclude the owner's assertion of copyright over the material.
