Energy efficient and environmentally friendly technology is being applied to stabiliser solutions aimed at ferries and cruise ships
“Every time we discuss newbuild projects, we face green and environmentally friendly topics. This is the main focus for a ferry and cruise operator.” So said SKF director of fin stabiliser and steering gears Christopher Schnäckel, a man who knows a lot about how current trends are shaping future plans.
The company is applying fuel and environmental efficiency to its products. At the beginning of last year it launched its Dynamic Stabilizer Cover (DSC), designed to reduce drag and improve the efficiency of passenger vessels equipped with SKF retractable fin stabilisers type S and Z. When a vessel is in motion, the fin box opening in the side of the hull creates turbulence, increasing drag on the vessel.
“The fin box opening causes a lot of drag and therefore creates a lot of fuel consumption,” Mr Schnäckel explained. “We wanted to close these openings to support the operator in reducing propulsion power and so being more environmentally friendly and reducing the fuel consumption.”
The DSC uses two specially shaped air cushions, fitted to the top and bottom of the fin box with small steel rails. In normal operation, the cushions are inflated using compressed air from the vessel’s existing pneumatic systems. Inflated, the cushions form a cover over the fin box opening. When the stabiliser fin is to be extended or retracted, air is released from the cushions by opening the valve. The cushions are then deflated by the water pressure outside the hull, creating room for the fin’s movement. When deployment or housing is complete, the cushions can be re-inflated. Control of the cover is fully integrated into the stabiliser fin control systems, requiring no additional action by the crew.
SKF said that closing the hull openings reduces drag by up to 90%, leading to a 1% to 2% reduction in fuel consumption each time the cushions are inflated.
The product will be tested by a large cruise operator this year and Mr Schnäckel said he hoped it would be ready to go to market by the end of 2018.
The company has another product in the pipeline: Eco Mode is being launched at SMM this year, with the aim of making stabilisers more intelligent and reducing fuel consumption. “Two big stabiliser fins in operation cause drag, but crew are not sure if they need one or two fins in operation. Our software detects when water is calm and sends a message to say only one fin is needed,” explained Mr Schnäckel.
Elsewhere, GEPS Techno has also applied an energy efficient technology to its stabiliser solution: Green Stabiliser Integrated with Recovery of Energy (GSIRE) is a passive anti-rolling tank for hulls. It consists of a tank filled with water positioned on the beam of the vessel. Vortex chambers are placed on either side and the water follows the lead of the chambers, stabilising the vessel. The GSIRE produces electricity from the waterflow, of up to 250 kW capacity, via turbines in the vortex chambers that are turned by the water. The return on investment is estimated at five to seven years.
The GSIRE was retrofitted from an existing flume tank space below the bridge deck on research oceanographic vessel Thalassa in September 2016 in a pilot project. Its sea trial result is approximately 50% roll reduction and 90% at peak period. GEPS Techno installed two 15 kW capacity turbines.
GEPS Techno commercial director Audrie Jordan said “We are not yet producing enough electricity to reduce fuel consumption on Thalassa, but it is generating electricity to the main switchboard.” She added that there was the possibility to store the electricity produced on a battery, which could be used in case of a sudden loss of power. The company is working with Bureau Veritas (BV) to certify this. The switchboard electrical installation has already been certified by BV.
She added: “It is the only stabiliser that is producing added value [through the creation of electricity].”