Yacht & Coast


RotorSwing steadies motor yachts up to 30m

July 21, 2013 by robert in Featured, NL Excel with 0 Comments

RAAMSDONKSVEER  _ Boats give you more rock ‘n roll than your stomach can handle? Don’t call a doctor. Call Theo Koop, founder of RotorSwing Marine NV, maker of the first electrically powered roll damping system for motor yachts of up to 30 meters. “Generally speaking a reduction of up to 90% in boat’s roll motions is achievable,” Koop tells the trade magazine Jachtbouw Nederland.

He says his electric RotorSwing kills a boat’s rolling better at lower speeds than conventional fin systems. That’s because the latter need substantial boat speed to be effective as the fins are kept small to reduce drag and damage. In shallow waters, fins are vulnerable. RotorSwing’s retractable rotors swing out from the hull when the engine is in gear. When it goes into idle, they fold back.

Koop’s RotorSwing is the first fully electrically driven, non-hydraulic roll damping system for yachts up to 30 meters. It exploits the Magnus Effect named after 19th century German scientist Heinrich Gustav Magnus. He discovered that a spinning object moving through space (or water) creates lift as it builds up more pressure on one side than the other depending on the spin direction. You see that lift in the arc of a soccer ball kicked by people who bend it like Beckham.

Koop uses the lift created by spinning cylinders in glass fiber tubes to steady a boat rocked by sea waves or the wake of passing vessels. “This is a tried and tested concept in super-yachts,” he says. “We just downsized it.” Koop says the RotorSwing works at speeds of 3 to 14 knots. At the push of a button, the rotor cylinders emerge from the hull. In only 0.8 seconds, the rotors reach 1,000 RPMs. The RotorSwing uses a nominal 1,000 watts per rotor. The rotors themselves have no impact on steering and, unlike fin systems, can be mounted anywhere.

Koop says he is currently testing “if we can place the rotors off the transoms of fast ships” and is pursuing industrial applications for his RotorSwing, notably for stationary vessels. Large dredgers, for instance, that help build wind parks at sea and need to dump their loads with precision in very exact locations.



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