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Sustainable Methods for Optimal design and Operation of ships with air-lubricaTed Hulls

Air lubrication of Ship hull a large potential gain in hull effciency of up to 20%. SMOOTH seeks to fill missing technology gaps and enable air lubrication of hulls within normal European shipbuilding and operation practice for both inland and coastal ships.

Tags: Water


While the basic concept of air lubrication is old, limited serious research has been performed. It was the PELS project, a Dutch national project that made a positive change. This project demonstrated that a positive overall energy gain can be achieved in all operational conditions with air lubrication. The required technology itself is new and requires further exploration. Based on the findings from the PELS project, the SMOOTH consortium estimates that ship hull efficiency improvements of up to 20% will be feasible. Such a step forward would be beneficial to the environment since the considerable reduction of fuel consumption will have its effect on the CO2, NOx and soot discharges. A reduction of fuel consumption will, of course, also be welcomed by the European shipping business since it will result in a reduction of costs.

European policies are addressed in a number of ways: the noticeable reduction of the operational costs by reducing the ship’s resistance, the enhancement of the quality and operational safety of the transport process, and the safer transport of crude oil and other dangerous and potentially polluting goods. The SMOOTH project facilitates the inter-European knowledge exchange, by providing a platform of co-operation for SMEs, companies and research institutes from six different European states, including and candidate country Turkey.


As air lubrication has been successfully tested for model ships, new products (in terms of suitable ultra repelant painting systems, ambient and functional air distribution and control systems) need to be developed further to apply this technique to vessels. The resulting verifiable and measurable objectives for the Smooth project are:

  • to provide validated (finally tested on model scale) computational tools for a real ship design
  • to validate scale effects of air lubrication
  • to evaluate the economy of air lubrication in practice and demonstrate the concept at full size on an inland vessel.
  • to prepare the safe introduction of air-lubricated ships in practice.

The strategic objective of SMOOTH is to apply air lubrication to ships and to provide the necessay new products in terms of control and paint systems to introduce air-lubricated ships. These ships may utilise micro-bubble (MB), air-film or air-cavity systems (ACS), for inland and coastal navigating ships with relatively shallow drafts.

Description of work

SMOOTH has defined a number of work packages.

WP1: Project management

WP2: Experiments on air films

WP3: Scale effects and sea trials

WP4: Model tests on air films

WP5: Model tests on micro-bubbles and air-cavity ships

WP6: Economic plus risk evaluation

WP7: Evaluation and dissemination

The techniques surveyed in SMOOTH for practical application and implementation in the coming generation of European ships will include in addition to improved drag and power-reduction , other innovations such as better stopping and manoeuverability.

Novel painting systems for ships and new air-control systems aboard ships will strengthen the position of the European shipbuilding industry represented within the Smooth consortium.


SMOOTH has the following deliverables:

D1.1 Project manual

D1.2 Management reports every six months, short summary reports every three months

D1.3 Mid-term report of the projects

D1.4 Project progress reports with cost statements, every 12 months

D1.5 Work package progress reports, i.e. mid-term, and final reports on each one

D1.6 Project completion reports

D2.1 Overview of the state of the art

D2.2 Overview applicable to super water-repellent (SWR) coatings for maritime applications

D2.3 Stability of air films and parameters that influence it

D2.4 Theoretical description of the phenomena

D3.1 Scale effects on air-film lubrication

D3.2 Scale effects on air lubrication in general

D4.1 Stability of air films on curved surfaces

D4.2 Effectiveness of air films in service

D5.1 Optimised design of an air-lubricated ship

D5.2 Validated design strategies

D6.1 Initial risk assessment for air-lubricated vessels

D6.2 Final risk assessment of air-lubricated ships

D6.3 First full-scale results on micro-bubble lubrication

D6.4 Equipped with a complete SWR coating of Akzo Nobel, the same barge is tested with air-film lubrication

D6.5 First large-scale tests with integrated air-supply system.

D7.1 Workshops, seminars and international conferences for dissemination of results and demonstrations

D7.2 Design guidelines for air-lubricated vessels

D7.3 Website