Merchant ship operators are eagerly looking for fuel cost reduction, today more than ever. Fuel consumption is largely dependent on the hull water resistance, of which the friction part is by far the most (up to 90-95%). Reduction of friction by non-polluting air “lubrication” affecting the innermost part of the boundary layer (e.g. micro bubbles) or separating the water from part of the hull (air cavities, air cushion) are old means that can still be subject to innovations.

Since some time the Technical department of Stena Rederi AB has pursued the air cushion concept for application to various types of hulls. Right now model experiments for a product tanker are going on at SSPA’s test facilities. A large scale outdoor demonstrator model is being constructed and instrumented by SSPA. An investigation program is scheduled for the first half of year 2010, to be performed by SSPA.

The solution has to be feasible and economically viable. Before entering into a new-building program it is necessary to confirm the total power reductions obtained in laboratory experiments, and to know how the vessel behaves and how the air system will be controlled in various environmental conditions.