Technical bulletin November 2015.

Fins versus WING stabilizersSummary:

The “stabilizer world” is a small one. The emphasis always has been mainly on roll damping during cruising. The last 15 years, after the introduction of the ZeroSpeed systems for the Superyachts, the majority of the manufacturers completed their portfolio with systems having both possibilities. Only a few years ago the popularity of the Magnus effect system gained interest. Quantum was in the front row with their MagLifts for the larger yachts and professional vessels, whereas RotorSwing Marine successfully introduced a full electrical system for the midsize yachts. But the market still suffered from the lack of well-engineered and reliable retractable fin systems for medium sized motoryachts.The Dutch design team of Quantum Controls and RotorSwing Marine have now created a completely new line of retractable equipment in which Pitch, Roll, Trim, Dynamic positioning and Emergency propulsion are combined. No more problems of fitting fixed fins within the vessel’s envelope, the WING motion control system folds back against the hull, completely safe from damages and with an enormous freedom of sizing.

After many years of manufacturing retractableRotorSwing Magnus stabilizers we were asked byour customers if we could come up with aretractable system that also could cope with highercruising speeds. The Magnus effect cylinders docreate an enormous stabilizing force for speeds upto maximum 8/10 knots, but over that speed the“drag” penalty plays its resistance toll. This dragresults in speed losses and increased fuelconsumption. Although we found a solution to overcome thisdrawback by “folding” the rotors backwards as in ajet fighter plane: the patented RAKE system.However, for vessels with higher cruising speedsthis drag penalty is still present.

Using foil shaped profiles seemed to be the answer.Aircraft wings have the functionality we were lookingfor. In contrary to the “normal” stabilizing fins thatare typically of Low Aspect Ratio (height divided bythe average width), we researched in the use of aHigh Aspect Ratio profile. The advantages seemedhuge and we started developing a new line of rolldamping equipment: the WING Stabilizers.Advantages are the preferred low drag, high lift andfunctionality over a wide speed range. Particularly inmedium to high speeds this is a great advantage incomparison with traditional fin stabilizers and ourown Magnus effect stabilizer system.

During extensive testing on our demonstrator, a Linssen Grand Sturdy 500, we found the system being extremely universal. We therefore call it a “motion control” system. Worldwide Patents are pending.

Retractable against the hull Roll damping during cruising ZeroSpeed roll damping Dynamic pitch damping Static trim adjustments Dynamic Positioning (DP) Emergency Propulsion (EP)

Please look at the below cross sectional drawing of the Grand Sturdy 500. It explains the forces working on the hull during roll damping.

RotorSwing Marine BV, Schuttersstraat 26B, 6191RZ BEEK, Holland.www.rotorswing.com T:+31 46 423 4206

The Grand Sturdy 500 is a typical Dutch trawler type displacement vessel. The maximum cruising speed is around 10 knots. Let us start to determine what size of regular fins would be required. We make use of the well-known and commonly used formula.

Vessel data:Displacement (D) 35 TonMax cruise speed (V) 10 knotsMetacentric Height (GM) 1,5 mBeam (B) 4,8 m

Taking into consideration the vessels “envelope” (the dashed line on the left side of the drawing) to safeguard the protruding fins from damage, the maximum allowable size is for each fin 0,6 m2.

The next steps:1. What is the Lift force of such a fin of 0,6 m2 at 10 knots? We assume the Lift coefficient (Cl) 0,8 and the

basic formula: 0,5 x rho x v2 x A x Cl results in a Lift of 6.605 N

2. What is the Lift force of a WING of 0,36 m2 at 10 knots? (This dimension is based on the model WING fitted under the demonstrator. It can be easily enlarged because of its retractability). We know the Lift coefficient is higher and with Cl=1,2 this results in a lift of 5.944N. A lower value, of course, the WING area is quite a bit smaller in area.

But look at the moment arm! For the fin the total stabilizing moment is 6.604 x 1,52m= 10.038Nm For the WING Stabilizer this moment is 5.944 x 2,38m= 14.147Nm

The stabilizing moment of the WING is 14.147 divided by 10.038 is 1,41 times better!!!

Conclusion: our retractable system will beat the standard, non-retractable fin, with 40%!

RotorSwing Marine BV, Schuttersstraat 26B, 6191RZ BEEK, Holland.www.rotorswing.com T:+31 46 423 4206

Advantages:

Extremely low drag while retracted. The WING will be folded backwards against the hull. For special applications the WING can be retracted in a cavity.

Universal positioning, best near the transom. In contrary to regular fin stabilizers that need to be positioned near the amidships to avoid steering problems, the WING can be best placed near the transom. This opens a possibility for Pitch Damping, an option available.

High Aspect Ratio wing with low drag penalty. The foil shape of the WING and the streamlined pivoting unit results in a low drag and results in a large moment arm.

Bilge keel function when retracted. As an option the control system can be programmed in such way thatthe WING will be retracted in a vertical position. The shape will then act as a bilge keel.

Raked wing for high speed applications. Like jet fighter planes the WING can be deflected backwards into a RAKE (Patented in this application) position. Minimizing the resistance even more.

No steering effect. Due to angular position of a regular fin, a portion of the Lift force is deflected sideways resulting in a steering component. The horizontal position of the WING is without such negative side effect. And thus no loss of energy.

All actuators are inside the vessel. The majority of repairs or regular maintenance can be effectuated with the vessel in the water. Besides the drive train with no wearing parts, all the drive components are situated inside the vessel. No expensive dry-docking and waiting lists required.

Optional winglet Lift increasers. Like modern aircraft the WING can be fitted with a winglet. Only if installed near the transom where the winglet can disappear behind the transom.

ZeroSpeed. When wagging the WING over its vertical shaft over a large angle, a generous Lift will be generated, applicable for ZeroSpeed. This ZeroSpeed is part of our patent application of this remarkableand unique motion control system.

Dynamic positioning (DP). In several situations, depths make it impossible to anchor. We are developinga control system that allows the WING system to keep the vessel in position making use of a GPS signal. See our YouTube movie.

Emergency propulsion (EP). The latest addition to this universal motion control system is the use of the WING as emergency propulsion or “homer” .

This product is a joint development and production of Q uantum C ontrols and R otor S wing Marine. The WING Stabilizer is the most innovative motion control system available today. Worldwide patents are pending .

RotorSwing Marine BV, Schuttersstraat 26B, 6191RZ BEEK, Holland.www.rotorswing.com T:+31 46 423 4206

The streamline drive unit with WING in “PARK”position, retracted against the hull.

During the ZeroSpeed mode theWING makes a wagging movementaround the vertical drive shaft.

When deflected to the “DRIVE” position theangular movement of the WING will be continuously adjusted by a 3Term+ electronic control system.

A unique application: DP and EP,Dynamic positioning andEmergency Propulsion in.

RotorSwing Marine BV, Schuttersstraat 26B, 6191RZ BEEK, Holland.www.rotorswing.com T:+31 46 423 4206