Understanding Ship Fin Stabilizers and Its Operation

In order to understand why Quantum Marine Stabilizers have crafted a superior series of ship stabilizers, it is helpful to delve deeper into how a fin stabilizer works. These details, alongside the specifics of our innovative designs, provide a clearer picture of the advantages of products produced by Quantum.

What is a Fin Stabilizer?

A fin stabilizer is located under the water line on the side of a ship’s hull, providing a roll damping effect, to counteract a ship’s natural roll. Many people never actually see a ship’s fin stabilizer until their vessel goes to the dry dock for surveys and hull inspections. However, the onboard officers and engineers are expected to understand the way the system functions and know the individual components of their fin stabilizer system.

The Components of a Fin Stabilizer System

Whether you are referring to a military vessel, commercial vessel, luxury yacht, or a cruise ship, stabilizer systems are generally all comprised of a series of main components:

  1. Two or four fins, configured in pairs, to port/starboard. Four fins positioned with a set forward and aft.  The fins are connected to a shaft that extends inside the vessel to the hull unit.
  2. Two or four hull units are hard mounted to the interior of the hull. They convert the hydraulic power to mechanical power via hydraulic cylinders. This is where the fins can be locked or rotated for underway and zero speed™ performance.
  3. One to four hydraulic power units are required to power the fins via the hull unit.
  4. The Ship Motion Controller (SMC) is the main controller that directs the fin angle and provides all the system logic control.
  5. The Human Machine Interface (HMI) allows for control and indicators that enable primary operation from the bridge and/or engine room. This panel can be integrated into a glass bridge via the SMC Controller.
  6. Two or four Effector Control Units (ECMs) are located near each fin stabilizer for local indication and close loop control of the respective fin.
  7. A Fin Angle Sensor measures the fin angle position, providing the information to the ECMs. A fin angle sensor is directly connected to the fin shaft.
  8. A Roll Sensor assesses the ship’s roll velocity and roll angle and feeds that data to the SMC.

Operation of a Fin Ship Stabilizer

  • Fin movement is controlled by a servo valve which directs oil to either one of the hydraulic cylinders, that rotate a tiller within the hull unit.
  • The SMC houses all the logic control and control algorithms to reduce a ship’s roll angle.
  • The ECMs provide fast and precise close loop feedback control to match the actual fin angle to the desired fin angle provide by the SMC.
  • Operation is controlled from the bridge or optionally the engine room via the HMIs’ where all user setting can be adjusted for optimal performance.

Ship Stabilization Systems from Quantum Marine Stabilizers

Learn more about the advanced features and benefits of Quantum’s industry-leading ship stabilizers by contacting us today.