Adding a "Whale Tail" to Reduce Fuel Consumption

Researchers from the Norwegian University of Science and Technology (NTNU) are testing a model “whale tail” that can be attached to ships. 

NTNU is conducting these tests in the Marintek Towing Tank in cooperation with Rolls-Royce and the British companies Seaspeed and MOST.

The person responsible for testing this invention is Eirik Bøckmann, a postdoctoral fellow at the Department of Marine Technology at NTNU. He has been working on this idea for several years.

The main goal of the whale tail is to help reduce fuel use by using wave energy to help the ship move forward.

A whale tail may not be the first thing that you think of when you see this invention— it looks like two wings, or fins that are attached to the front of the ship. But the principle behind the energy saving is about the same as in a whale tail, he says.

The waves that hit the ship model cause it to move, which in turn causes the fins to move up and down just like a whale tail would. The shape of these fins allows energy from the waves to help the ship move forward.

Preliminary results are very promising. “The foils reduced resistance on the ship by between 9 and 17 percent at wave heights of under three meters, under the conditions that we’ve tested,” says Bøckmann. This is a fairly normal wave height in the North Sea and the Norwegian Sea.

“The resistance can probably be further reduced by optimizing the ship’s hull for the wave foils. The foils also reduced the ship’s heaving and pitching by about the same amount as for resistance,” he continues. 

“We need to see how things work, and then choose the best way forward based on that,” says Alastair Sim, a technologist at the Rolls-Royce Strategic Research Centre.

Sim says that he sees a lot of potential for this invention if it works the way it is intended. Sim is responsible for evaluating new marine technologies and deciding what Rolls-Royce should fund.

It isn’t enough for the wings to just work. Other factors also play a role. For example, the wings also need to be able to take a beating and not destabilize the ship.

“Experience from similar ideas shows that collisions where the wings are damaged doesn’t affect the actual stability of the ship,” Sim says.

The shape and angle of Bøckmann’s fins are unique, but similar inventions have been tested and used previously.

Seaspeed works together with Rolls-Royce Marine and is supported by an official British innovation program intended to help develop fins like this for use in commercial marine transport.

Rolls-Royce Marine has collaborated with researchers at the towing tank for a number of years, but this specific project started in 2013.

Rolls-Royce Marine also recently signed a long-term research and development agreement with NTNU and SINTEF MARINTEK.

So how feasible is it that wave power will be an important part of seafaring in the future?

“There has already been small scale development of boats that use only wave power and have no motors,” says Ie-Bum Shin, who is a naval architect at Seaspeed. But it will be a long time before this technology can be used in full scale. The current goal is just to cut fuel costs.”