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Pels & Aces

A great partnership leading to even greater results.

SUSTAINABLE SHIPPING WITH THE REVOLUTIONAIRY AIR LUBRICATION HULL DESIGN

Damen has been looking at ways to promote sustainable shipping for years. Bodewes Binnenvaart, a Damen shipyard based in Millingen aan de Rijn, has been part of the PELS Project (Project Energy-saving air-Lubricated Ships) for more than seven years. By looking at air lubrication, PELS originally focused on sustainability using pushbarges. A real milestone was reached when the project partners took the decision to change over the bottom construction. This resulted in a new ship type: the air lubricated ship that we named the ACES, an acronym of “Air Chamber Energy Saving”. ACES has been patented by Damen and Marinvention. And tests and sea trials have proven that the new hull bottom can reduce fuel consumption by at least 15% a year on average.

Damen Shipyards partnered Marinvention

For the last seven years Damen's inland shipping specialist yard, Bodewes Binnenvaart, based in Millingen aan de Rijn, has been taking part in the PELS 2 project. With roots dating back to 1896, Bodewes focuses on newbuild, dry cargo and container barges, repair works and maintenance. To develop inland waterway innovations the Damen shipyard partnered Marinvention during PELS 2 and Maritime Research Institute Netherlands (MARIN), based in Wageningen. A great partnership leading to even greater results.
New bottom construction

We started with full-scale testing of the hull form but this showed that barge forms gave too much difficulty. Model tests were undertaken at MARIN’s basins in Wageningen and all of the necessary equipment was brought onboard as well and tests were carried out along the River Rhine and at inland waterway locations. Several loading conditions were tested. The next milestone was the decision to change over the bottom construction. A totally new concept, designed by Damen’s R&D department and Marinvention, using a corrugated construction was used on the model and after successful model tests this was also used on the vessel. Then the traditional flat bottom was changed to the air lubrication construction at full-scale. The vessel was tested in deep and shallow water, facing up and down river.
Annual savings of 15%

We concluded that the system itself was working very well but the outcome depended on the situation. When the vessel was sailing at lower speeds the outcome was much better, leading to vastly improved fuel savings. Results varied from a 5% fuel saving up to a 40% fuel saving. Overall, the project partners found that there were annual savings of 15% when calculating the results over a year using a normal sailing profile.
New ship type patented

We are very proud to have developed a completely new type of ship: the air lubricated ship. This offers many new possibilities. There has been a lot of research into all kinds of air lubrication systems before but none of them have worked until now. The construction itself is very simple and easier to build than the original double-bottomed construction. The corrugated profiles are welded to the plates so it easier for the welders. And this new corrugated construction turned out to be incredibly strong. Marinvention discovered that it was much easier to make a corrugated bulkhead for the longitudinal sailing direction. The height of the corrugation is where the strength lies. There is less wet area because the gaps are filled up with air and there is also a very small air system underneath which allows a small amount of air to be blown onto the propeller. The project partners found out that a little bit of air is actually very good for reducing the vibrations of the propeller.
Savings right from the start

If companies choose this construction on a newbuild vessel they will save a lot of money right from the minute they start sailing. It is also economical if a vessel needs a complete bottom repair or if companies want to change the CO2 footprint of an existing ship. This really is the first system to save fuel at a normal scale.
Possibilities for seagoing ships

As well as launching ACES, the partners are investigating using this type of bottom on a seagoing vessel, (up to a 360 m container feeder), and then they will also look at its potential for tankers. Seagoing trials are being carried out with the same model used for the inland waterways. If the outcome of the trials is positive the partners will construct a model of a seagoing vessel.
Next step: focus on tankers

The next step is further research into the tanker business. But there are several challenges to be addressed when it comes to the tanker market, such as the ADN regulations and the fact that the ACES would be a double-double bottom construction.