Contributed Content, Edited for Clarity and Length
In an active marine stabilizer system, there are four to five components that integrate to form a complete system:
- Hull unit – positioned internally, typically at the turn of the bilge. The hydraulic cylinders (or actuators), on top of the hull unit rotate the main shaft, which deflects the fin to the precise position directed by the control system. The main shaft, extends through the hull, with a tapered, hydraulic expansion coupling to secure a fin or rotor to the exterior of the vessel, typically amidships, inside the hull envelope.
- The HU2500 hull unit
- HPU – hydraulic power unit provides the fluid power necessary to articulate the stabilizer fins or rotors. Based on vessel requirements, there are many power and size options available. Manifolds are designed into the HPU to control the cylinder movements within the hull unit. Accumulators are integrated into the system to manage the load surges. Many new advances have been made to the HPUs relative to sound and vibration technology. The HPU QP7575
- XT HPU – If an XT Fin is specified with an extendable and retractable foil, a separate XT HPU is required. It is designed to be independent of the main stabilizer hydraulic system, and uses eco-friendly hydraulic oil. The XT HPU is a constant pressure system, running only when required to position and hold the foil;
- Controls – essentially the brains of the system. Using the specifications of the vessel and interpreting the optimal response to a ship’s roll, starting from the roll sensor, directives are given to the hull unit and HPU, which drive the movements of the fins or rotors. Each vessel has unique hydrostatic characteristics, such as the roll period, vessel speed, metacentric height (GM), displacement, beam and sea state requirements; The 500S control passes directives to other system components
- Fins or Rotors – these are appendages, attached to the hull unit shaft, that are positioned on the exterior of the hull, typically amidships within the hull envelope. These are active systems that move per the specifications, algorithms and hydrostatic characteristics of the vessel.
Active Stabilizer Benefits for Military Applications
Quantum has been providing stabilizer solutions for military projects for the last 18 years. Through that time, there has been heightened awareness of the value of stabilization to military operations. Acute fatigue is the number one cause of injuries and fatalities at sea, which stabilizers definitely help to mitigate. The US Coast Guard conducted a study of 279 vessel accidents: of the seamen affected by those incidents, 33% of the injuries and 16% of the fatalities were fatigue-related. Another report, based on a fatal Navy collision near Singapore, concluded that severe fatigue was a major factor. Fatigue is just one factor – overall crew safety and the ability to perform many functions at a higher sea state, are other tremendous benefits.
In addition to 18 other military contract awards for foreign navies, Quantum is currently supplying the stabilizer systems for two ongoing, multi-year projects: 64 Fast Response Cutters (FRC) – US Coast Guard – Bollinger Shipyards/Damen Design
- 12 Offshore Patrol Vessels (OPV) – Royal Australian Navy/Lürssen Design
The value that stabilizers offer in safety, productivity and success to the overall mission, fully justify the cost. For additional information, contact Quantum Marine Stabilizers – firstname.lastname@example.org www.quantumstabilizers.com