THE POWER OF POSITIVE THINKING

Rune Garen uses his business development role at Kongsberg to pose some difficult questions

Rune Garen has seen a lot in his nearly four decades in the maritime industry. The naval architect and marine engineer, who is now senior vice-president for business development at Kongsberg Maritime, has a particular focus on hydrodynamics and told The Motorship in an exclusive interview that his job “is to try to connect new things that are coming up and consider how they will impact our industry.”

One of his long-held passions is that we should learn from nature. In our March issue, we quoted him making that point in a retrospective article looking at flapping foils as a means of propulsion. In our recent interview, he cited other intriguing examples.

One of the biggest paradoxes, he said, is the speed achieved by the fastest fish. A bluefin tuna, for example, is typically about 2m long, weighs around 200kg and can reach speeds of about 70km/h. Now imagine a towing-tank experiment with a ship model of those dimensions at such speeds, he said: the power needed would be about 75kW “but when you ask marine biologists if that is possible, they say no.”

In fact, tuna generate as little as 1.1kW, Mr Garen said, so “there must be something that we need to understand to close this gap.”

There is no single explanation, he went on. Its flapping tail clearly acts as a propulsive foil, but “how are they controlling and, most importantly, reducing not only the skin friction, but all the resistance elements they are exposed to?” There could also be effects related to the tuna’s mass-elastic system, in which its backbone stores and releases energy. “We need to dig into this”, he said.

Artificial intelligence

With the release in February of the artificial intelligence (AI) chatbot ChatGPT, some have expressed concerned about AI’s implications. But Mr Garen believes that shipping should embrace AI, saying that it would become “a layer above” existing control technologies. This, he said, “will enhance the way we might optimise vessel operation in the future.”

It might not initially take over ship operations, however. “My hope is that AI can help us in sorting out all the information that we are bombarded with … such that we can make better decisions than before.” But eventually, it “will become a very important part in assisting autonomy in the marine business”, but only when that becomes fully practical. For the foreseeable future, ships will still carry crew so AI will be useful in optimising the man-machine interface, he believes.

Both Kongsberg Maritime and Rolls-Royce Marine – where Mr Garen was director of propulsion research and technology before it was bought by Kongsberg in 2019 – had autonomous ship projects, with Kongsberg Maritime’s most advanced project being Yara Birkeland, designed to carry containerised fertiliser for Norway’s Yara from its factory in Herøya to its export terminal in Brevik.

Kongsberg provided much of its technology, including sensors for remote and autonomous ship operations and its electric drive, battery and propulsion control systems. It went into operation in 2021 as a crewed vessel but during this year and 2024, it is expected to become fully autonomous and to be approved for un-crewed operation.

Kongsberg has also developed a series of underwater autonomous vehicles (AUVs), of which Hugin Superior is the most advanced. It is used for subsea surveying and can operate at depths down to 6,000m. Vessels such as these will grow in number, size and capability, Mr Garen predicted, and he did not rule out the possibility of cargo-carrying AUVs in the future.

This would avoid wave-making resistance, which can lead to “devastating” energy losses, he said, “so if you can get rid of that troublesome resistance component by operating just under the wave affected zone … that's a very interesting prospect.”

Rim drives

One Kongsberg technology that is already saving energy is its patented rim-drive thruster concept, in which the thruster blades and a connecting yoke are fitted with magnets to form the rotor of an electric motor. The surrounding duct serves as a stator, creating a high-torque motor that is driven by its rim

8 Kongsberg’s patented rimdrive thruster uses thruster blades and a connecting yoke fitted with magnets to form the rotor of an electric motor rather than its shaft. This gives it a very quick thrust response – from zero to 100% in less than two seconds, he said.

This arrangement has other advantages – not least because there is no space required for an electric motor inboard. It is also quieter than other propeller arrangements, which reduces underwater noise pollution and could make it attractive for applications such as passenger shipping: two recently delivered passenger ships for Norwegian coastal services, Havila Castor and Havila Capella, are fitted with Kongsberg rim-drive bow thrusters.

Late last year, Kongsberg Maritime received its first orders for these drives to be used for commercial propulsion applications, marking a breakthrough into this market, Mr Garen said. They are to be fitted to supply and construction vessels for the offshore wind sector.

But rim drives are not suitable for every application. At low speeds – especially on vessels where bollard pull is important – the nozzle creates valuable thrust from the water flow that the propeller forces past it. But at higher ship speeds the nozzle becomes a drag, ruling the concept out for highspeed applications.

Cavitation

Mr Garen continues to thinking about future technologies, again taking inspiration from nature. Cavitation, for example: it is a perennial problem because of the damage it can cause to propellers, but in nature it has been put to good effect.

He referred to the mantis shrimp, which is a crustacean that typically grows to about 10cm long. It uses cavitation like a hammer to attack mussels to get at their meat: the cavitation force exceeds what the shrimp could deliver just from its muscle power.

In the same way, he wonders, is there a positive application of cavitation for shipping? It is a question that has intrigued him for several years; “these are complex things and it takes a lot to understand them. But once you have understood them, then you can start to speculate.”

This might seem vague, and he agrees that “there is a long way to go”, but he believes “we should take inspiration from considering how to turn a negative thing into something more positive.”