Rolls-Royce Introduces Revolutionary Retractable Stabilizers

The Best of Both Worlds!

Rolls-Royce is developing a new concept that significantly reduces the roll of a motor yacht when stationary by increasing the effectiveness of the folding fin stabilizers normally used for underway stabilization. The system uses a different fin profile and an advanced control system that keeps the fins ‘active’ when stationary, maximizing their effect in reducing ship motion. Scale model tests carried out at the Maritime Research Institute Netherlands (MARIN) in Wageningen December 2005 on a large motor yacht have proven the effectiveness of the design concept. The conclusion was: "The Innovative Rolls-Royce system works equally as well as similar systems currently on the market."

The new Rolls-Royce system gives yacht owners the best of both worlds in terms of stabilization performance with the advantages of a single system installation – providing optimum comfort at rest and at speed. Existing systems can be upgraded to improve performance at rest.

Features:

• Fins retract when not in use.
  
• Less appendage drag – increased vessel range
  
• Uses the proven Aquarius range
  
• Only one pair of fins required – lower installation cost
  
• 20-30% increase in performance when fins are passive
  
• Simple to retrofit to existing Aquarius systems
  
• Low power from quiet electro-hydraulic power unit

Advanced Control System

At the heart of the system is a new control and electro-hydraulic system that provides power to the fins when the vessel is stationary. Here's the sequence...

1. The control system senses the start of any roll.
2. Electro-mechanical power then passes to the fins.
3. Paddle effect of the fins generates stabilisation.
4. The effect accelerates a mass of water quickly, to provide the stabilization at rest moment.

Testing

During the trials program a number of different fin geometries, actuation speeds and control algorithms were tested and the data analyzed to determine the best overall configuration. Further testing on other projects has recorded similar roll reductions. An extract from the MARIN report stated "One pair of modified Aquarius stabilizers provides similar performance to two pairs of low aspect ratio fins."

Two Aquarius Folding Fin stabilizers are the key components to the system. Each stabilizer has a modified fin profile, as seen here...

Fact Sheet

(preliminary data)

New Orders...

Rolls-Royce has already received three orders for the new stabilization at rest system from the oceAnco shipyard in Alblasserdam, The Netherlands, for three yachts, all 1,850 tons displacement, 80-82 meters length overall, 13.8 meters beam, 3.6m draft, and a maximum speed of 19 knots. The roll period for the yachts is estimated at just over nine seconds. The yachts are due to be delivered in December 2006, summer 2007, and during 2008.

During 2005 Rolls-Royce was finalizing its plans to develop stabilization at rest for retractable and non-retractable fin stabilizer systems. During the second half of 2005 oceAnco requested a stabilization at rest feature, and both companies jointly worked towards this solution.

Two standard Aquarius systems had already been supplied to the yard, which was in the process of constructing two of the yachts. After detailed discussions, a contract was placed to upgrade the systems to provide stabilization at rest. Immediately, a third order was placed, with system delivery at the end of November 2006. Sea trials on the first yacht to feature the new system will also take place in November 2006.

Rolls-Royce is anticipating interest in the system not only from owners of new-build yachts, but also from owners seeking retrofits to existing Aquarius systems.

Rolls-Royce is already building on its success in the yacht market by introducing a smaller unit, the Aquarius 25 for up to 3.5 sq. m. and an Aquarius 100 of up to 8 sq. m.

For further information, contact:

Paul Crawford, Regional Sales Manager
Rolls-Royce Power Engineering
Tel: +44 (0)1383 826 825
Email: paul.crawford@rolls-royce.com
Website: www.rolls-royce.com