Quantum Marine Stabilizers
Hull Unit Series for Fin Stabilizers

Hull Units for Fins

The hull unit is one of the major component parts in a Quantum stabilizer. It interacts with the controls, stabilizer fin and hydraulic power unit to deliver precise movements of the fin as is commanded by the control system.

The hull unit is installed in the turn of the bilge with the main shaft penetrating the hull providing the apparatus to connect the stabilizer fin. The hydraulic cylinders on the top of the hull unit, rotate the main shaft, which deflects the fin to the precise position as directed by the control system.

The installation is managed through the supplied welding bushing. The main shaft features a tapered hydraulic expansion coupling for the secure attachment of the fin, and a spline connection to the tiller and hydraulic cylinders. These precise machined components promote a smooth transfer of energy from the hydraulic cylinders to the stabilizer fin.

The hull unit is simple to maintain during normal operation, with stainless steel components used to minimize corrosion. Internal porting is built in, providing grease points that are accessible from inside the vessel, making routine maintenance easier. The unit is designed for replacement of the lower seals and bearings during regular scheduled docking. All other internal maintenance and service work can be accomplished with the vessel in the water.

All standard and HD hull units in the Quantum model range can be upgraded to support the installation of XT™ fins. Hull units can be delivered with the appropriate XT™ components preinstalled for conversion at a later date.

For safety and emergency operations, all Quantum hull units are equipped with centering cylinders. These cylinders engage the tiller and have the capacity to center and lock the fin in the mid position should there be a failure of the main cylinders, hydraulic power unit or control system. The cylinders can be deployed from the main power unit or if required, can be deployed using a manual hand pump.

Hull Units for Fins & Rotors

Hull Unit Series LOA Range (m) Standard fin Range (m2) XT Fin Range (m2)
QC1500 36-50m 1.5 - 3.5 3 x 4
QC1800 45-60m 3 - 5 4.5 x 5.7
QC2200 55-65m 4 – 6.5 6 x 7.8
QC2500 60-90m 6 – 8.5 8 x 10.4
QC3000 80-110m 8 – 10.5 10.5 x 13
QC3600 100-152m 10 – 15 15 x 19.5
QC4000 115-200m 12 – 16 15.5 x 20
The ML300/ML400/ML600 Series
Hull Unit Series LOA Range (m) Rotor Length Rotor Diameter
ML300 35-50m 2500mm 344mm
ML400 45-70m 3220mm 460mm
ML600 100-160m 4000mm 630mm

Designed using the latest technology and high-quality materials, the ML Semi-Retractable Series system offers the best performance of any system where significant roll reduction is required at loitering speeds.


Simple Installation: The stabilizer unit is delivered fully assembled with minimal disassembly required for installation. Since no customized hull pocket is required for the rotor’s stowed position, complicated hull shape fabrication is avoided.


Smooth Operation: The unit provides smooth power transfer from the ship’s hull to the rotor via precision roller bearings used in both the spin drive shaft and the main shaft.


Precision Control: By varying the RPM and direction of rotation of the tube, the lift force can be controlled with razor sharp precision, resulting in instantaneous response.


Efficiency: When properly sized and operating within acceptable vessel speeds, rotary stabilizers provide exceptional hydrodynamic efficiency compared with other stabilizer systems available.


Safety: The rotor’s hydraulic system is equipped with an automatic retract mechanism to allow the rotor to swiftly stow in case of impact during operation. While not in operation, the rotor is elegantly stowed along the hull, where it presents minimal possibility of impact and minimal effect during maneuvering conditions. In case of severe impact, half of the rotor tube will break away, in a design feature intended to sacrifice the rotor unit in order to preserve hull integrity.

Gear assembly and hydraulic swing cylinder.

Sectioned view of the foil drive cylinder with shaft and lower linkage.
  • Spin Control Manifold
  • Swing Hydraulic Cylinders
  • Swing Drive Housing
  • Hydraulic Spin Motor
  • Servo Control Valve
  • Main Hydraulic Control Indicator

Do you need more information?

Mark Armstrong
Technical Sales Manager
Write Email to Mark