It all started when…
The fluidic technology that the Marine Bubble Flow air lubrication system is based on was developed for NASA in the 1960s. Fluidic technology relies on the viscous properties of gasses and fluids to create smart devices without any moving parts, that can control and switch flows. The thinking behind the MBF system is that if a ship's hull can be covered with air bubbles to provide lubrication, friction or drag will be reduced and fuel saved. It is a simple and appealing idea particularly when fuel prices are rising due to political and regulatory pressure to reduce emissions such as the European Union Sulphur Directive which stipulates a maximum 0.5% sulphur content for ships in all EU waters by 2020.
The costs to the shipping industry of complying with this directive are huge. The shipping industry consumes an estimated 4% of global fossil fuels and produces 2.5% of global GHG emissions. Every percent saved on emissions and fuel use has a big impact on the fleet operating cost.
The challenge of air lubrication lies in scaling up the results from controlled model testing in towing tanks to large scale, real life operating conditions. To date the prevailing method of Air Lubrication Systems providers has been to make a large number of holes in the bottom of a ship and pump air from surface to create a layer of air bubbles underneath the hull. Net drag reduction levels of between 2-12% have been measured. Net fuel savings of around 5% were reported with this approach. Alternative methods, using Air Cavities, have been tried on inland barges, but the net efficiency gains are still to be independently validated. However, both methods breach the integrity of the ship's hull, which introduces additional cost and complexity on, for example, double-hulled tankers.
Marine Bubble Flow B.V. has solved the scaling issue without requiring alterations to the ship's structure. The potential efficiency gain is expected to be significantly higher at 10-15% than with current ALS systems offered, particularly for large vessels with flat bottoms, such as container ships, LNGCs, Ro-Ros etc.