Gyro History
· Gyro stabilization concept developed in the early 1900’s.
· Application to recreational yachts never developed due to the constraints on weight, size, power consumption and manufacturing complexity.
· Seakeeper eliminated these constraints with state-of-the-art engineering and manufacturing and provides an effective product for the recreational yachts.
Boat Roll Principles
· All boats have a natural or resonant roll period which is typically in the range of 2 to 5 seconds.
· When the wave encounter period is close to or matches this natural roll period, boats typically roll 3 to 5 times the wave slope.
· A wake from a passing boat often sets up an oscillation at the natural roll period even if the wake period does not match the natural roll period.
· All stabilization systems (fins, gyros, tanks, flopper stoppers) reduce roll at the boat’s natural period; however, an actively controlled gyro is the only stabilization device that will reduce roll at all speeds in all sea conditions.
Gyro Principles
Remember the toy gyros we all played with when we were children... and do you remember the force you
felt in your hands as you moved the gyro? You may also have held the axel of a bicycle wheel between your
hands as you gave the wheel as spin... do you remember how hard you had to work to tilt the wheel? What
you were feeling was the force of gyroscopic precession... the wheel was creating force that resisted your
attempts to tilt it off it's axis... much like a spinning top. Seakeeper works on the same principles.
· Gyros are the only practical solution at zero and low speed for boats with short roll periods if considers size, weight, power, and added resistance.
· Seakeeper’s actively controlled gyro varies the precession brake resistance to maximize the roll reduction in low and high sea states.
· Passive gyros operate with a fixed brake resistance which limits roll reduction in low sea states and requires that the gyro be shutdown in high sea states.
What is a SeaKeeper Gyro?
Seakeeper is a control momement gyro... the same technology that is used to stabilize spacecraft. Seakeeper is typically mounted anywhere inside the hull structure aft of midships. Since the gyro is inside the hull... completely internal... there is nothing in the water to damage or corrode. Seakeeper requires minimal maintenance. The Seakeeper tilts forward and aft in response to boat motion... this is called precession. As the gyro precesses it creates a powerful righting torque of three and one half tons that virtually eliminates boat roll.
The active brake is unique to Seakeeper. It functions as a hydraulic dampener that uses motion sensors and computer-control to adjust the rate of precession to match sea conditions. This results in maximum energy transfer to counter boat roll in any sea condition at any speed or while docked or drifting. |
What's Inside?
The Seakeeper ball contains a precision machined and balanced 400 pound stainless steel flywheel. A brushless direct drive DC motor spins the flywheel at 10000 RPM in a near vacuum. Seakeeper's vacuum-sealed rotating parts, single piece high strength steel forged flywheel, pre-pressurized hydraulic braking system and liquid cooled flywheel bearings and motor drive electronics insure trouble-free operation with minimal service and maintenance. |
The Seakeeper is technologically advanced but mechanically simple. There are actually only two major moving parts, the flywheel and the active brake. Proven components are employed in a new and unique way for reliability. · Bearings from the high speed machine tool industry where long life and low heat generation are critical · Motor drive electronics from medical centrifuges and machine tools · Gyro control electronics from marine diesel control |
How Does It Work?
· The flywheel rotates at high peed about a vertical axis inside a vacuum tight enclosure.
· The enclosure is mounted so the flywheel can rotate (precess) about a transverse gimbal axis.
· Boat roll causes the flywheel to generate a torque about the gimbal axis called the precession torque.
· The gyro controller sends commands to the hydraulic brake to regulate the precession torque and
thereby generate and control a second torque called the gyro torque that opposes boat roll.
Roll to port Negative precession Anti-roll torque to stbd (shown in blue) | Roll to stbd Positive precession Anti-roll torque to port (shown in blue) |
Anti-roll torque is created only while the gyro is tilting fore an aft!
What Can Seakeeper Do for You?
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S.W.A.T. is an authorized distributor and factory-trained installer for the Seakeeper Gyro. Visit Seakeeper for more information, technical details, photos and video of Seakeeper in action. |
Sea Worthy Advanced Technologies, Inc. • Conroe, TX 77385 • 281.296.2929 |