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Model of a Two-Fin System

Air Activated Fin Stabilizers

Since the invention of the activated fin stabilizer in the early 1920's, all stabilizer systems have been operated hydraulically or hydroelectronically, as these were the available technologies. In the past few years, the more advanced pneumatic technology has emerged and proven its superiority in various application fields. The Gyro-Gale System is a classic application of the advanced pneumatic technology in the stabilizers field.

Principles of Operation

Generally, a rate gyro is continuously activating and positioning two (or more) aerofoil shaped fins, which project from the sides of the vessel, so that one fin develops upward lift while the other develops downward lift. Thus, the combination produces the required stabilizing torque, which counteracts the rolling force induced by the wave action. Consequently, the performance of the stabilizers is entirely dependent upon applying the correct amount of righting torque at precisely the right moment.

In other words, an efficient system should feature a variable incidence fin which is capable of adjusting its angle of attack to the water in proportion to the speed of the vessel to produce the correct amount of lift through the full range of speed. In addition, the system should offer a control unit and working medium which permit the activation of the fin simultaneous to the response of the gyro.

Pneumatic Stabilizers

Gyro-Gale is a pneumatic controlled and operated system, providing comfortable, smooth, quiet, and reliable air-cushioned stabilization. The system comprises the latest pneumatic equipment and devices, most are standard industrial items. These components, when interconnected, provide the simplest, yet most advanced and efficient stabilizing system. It stops the roll almost before it starts.

Gyro-Gale Installation Features

  • No requirement for electric connections.
  • No requirement for hull strengthening at fin locations.
  • No need for through-hull stuffing box or gland seal.
  • Light weight equipment, 272 lbs. for the two-fin system, reduces installation time (40 man hours) and cost.

Operation

  • Simple "on-off" pneumatic switch for operation.
  • No adjustment required for various sea conditions.
  • Water-lubricated fin bearing for smooth and quiet operation.

Performance

  • Variable incidence fin, self-adjustable for various vessel speeds, obtained by pneumatically balancing the hydrodynamic water pressure on the fin, thus providing maximum stabilization (up to 90%) through the entire range of speed (4 to 50 knots).
  • Control unit with one moving part, yielding nearly simultaneous (0.23 sec.) relay of gyro response to the fin activating mechanism.
  • Frictionless air as working medium, for fast response and added comfort through air-cushioned stabilization.
  • Anticipation of roll and instant reaction to it within 3°.
  • Minimizes pitching motion (Quadra Fins only).
  • Various fin configurations for optimum performance with various hulls.

Maintenance

  • Fully automatic self-cleaning and lubricating, just add lubricating mineral oil every 250 hours of operation.
  • Working medium air, never needs refill.
  • Easily repairable interconnecting nylon tubing.

Safety

  • Breakaway fin bearing to shear off from the hull under heavy impact, thus leaving the hull intact.
  • Operation on low air pressure ( l00 psi) in the event of damaged connector, only clean air escapes, as opposed to the highly pressurized flammable fluid used in hydraulic systems.