‘The World’s First Electric Retractable Magnus Effect Stabilizer’

RotorSwing is the first fully electrically driven, non-hydraulic roll damping system for yachts up to 30 metres based on the Magnus effect. Instead of traditional fins, the system uses rapidly rotating cylinders which, subject to the direction of rotation, generate an up or downward pressure.

The biggest advantage of RotorSwing in comparison to a fin driven conventional system, is the greater roll damping at lower speeds. To achieve effective roll damping with fins it is necessary to reach a substantial speed through the water. This is partly due to the fact that often, the surface of the fins have been designed to be as small as possible to reduce the risk of damage. In shallow water, protruding fins are, in particular, very vulnerable.

RotorSwing features retractable rotors, eliminating the risk of damage. The retracted rotors remain largely within the turbulent boundary layer1 of the vessel so that any resistance is negligible.

If the rotors are in use in the “Drive” position, they can protrude outside the hull of the ship. However, should the engine be put in to neutral, the rotors automatically retract. This prevents damage during maneuvering and berthing at quays, in locks and ports.

The rotors do not have any effect on the steering and therefore, unlike fin based systems, can be mounted at a position of choice. For the majority of yachts, this is likely to be dictated by the onboard available space for the compact electric motor. It is even possible to mount the rotor at the stern which, in particular for fast-moving yachts, may be preferable.

RotorSwing is the first fully electrically driven, non-hydraulic stabilizing system based on the Magnus effect. No expensive, vulnerable hydraulic pumps, cylinders or high pressure lines and no risk of oil leaks on board. RotorSwing is a product from RotorSwing Marine, founded by Theo Koop. Theo, the founder and owner of the former KoopNautic Holland, is, for good reason, known as “the Godfather of stabilizers”.


• Silent operation (full electric drive)
• No hydraulics
• Quiet (especially at zero speed)
• Retractable (safe during transportation)
• High damping (also at low speed)
• Zero Speed (optional)
• Compact and easy installation
• No valuable loss of space on board
• Higher momentum (better damping)
• High static heel (best performance in following seas)
• RS 140 comparable with 1.1 m2 fins
• No steering effect (even transom mount is possible)
• Optional Rake control (allows use at higher speeds)
• 3 term controller (angle- velocity-acceleration)
• Easy to operate (park – drive)

• Maximum power (1500w per rotor)
• Average consumption (1000w per rotor)
• Voltage (230v 1 phase AC)
• Weight (139kg per rotor)
• Panel dimensions (110mm diameter)
• Steel weld bushing (214mm diameter, 250mm high))
• Rotor material (Epoxy / glass laminate)
• Elbow material (Cast steel with special coating)
• Shaft material (stainless steel)
• Emergency operation (Hhand wheel)
• Grease lubrication (via nipples (2x))


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stabilisator RotorSwing - DMS Holland - Dynamic Marine Systems

RotorSwing in action. Watch the movie.

stabilisator RotorSwing - DMS Holland - Dynamic Marine Systems

RotorSwing in action with Forced Roll.
Watch the movie.