‘Gravity in a bottle’ is how this company reduces boat-roll and could potentially transform everyone’s experience on the water.
In 2014 Seakeeper became somewhat of a marine technology marvel when the company released a gyroscope that could reduce boat-roll significantly.
Designed to virtually eliminate boat roll on vessels 23’ and up, Seakeeper only requires modest electrical power, has no outside appendages, and can be installed virtually anywhere on board a vessel.
Stability has often been a topical safety issue for marine vessels from both a leisure and work perspective. Research into seakeeping goes deep, and the rough waters of initial systems have come to the surface thanks to engineers that have been able to perfect different seakeeping technologies.
Gyroscopes have become one of the penultimate ways in which boat roll has been addressed, and there’s sound science to back up why it is one of the preferred ways to keep stability for smaller vessels.
Last year Seakeeper 1 was released, and with the release, smaller boats could see roll reduced by up to 95% when on the water. According to the company the Seakeeper 1 is designed to nearly eliminate roll on vessels of 23 to 30 feet (7 to 9 meters) or up to 5.5 tonnes.
The system achieves this by having a flush mount system that is completely contained, and no part of the sphere of the gyroscope hangs below the system. Because the gyroscope is relatively small at only 15.68 inches in height it can be installed relatively easily and even below the seat. The system is also energy efficient since it runs on 12V DC power, and the vacuum in the system only consumes 55 amps.
Another feature that makes it so compact is the fact that it features a unique flywheel and small envelope that allows it to start stabilizing a vessel in just 15 minutes.
Seakeeper President and CEO Andrew Semprevivo said upon release; “The Seakeeper 1 is the smallest, most innovative, and most efficient gyro stabilizer on the market. We realized our goal to bring stabilization to the masses.”
With the release of the system, 12 boat manufacturers already started to plan how to integrate the Seakeeper 1 into their newest models.
Why Gyroscopes?
When you look at the modes of motion vessels are subjected to, gyro-stability becomes one of the preferred ways to stabilize vessels.
A condensed look into it is provided by the research in Non-linearity Analysis of Ship Roll Gyro-stabilizer Control System, which offers a look into active gyro-stabilizers, twin gyro-stabilizers, and ship roll motion.
Way back in the 19th-century, mechanical gyroscopes were already changing the face of engineering. Displacement gyroscopes and rate gyroscopes are the historical gyros with a toroid-shaped rotor that rotates around its axis.
This changed in the 20th century when optical gyroscopes started operating by sensing the difference in propagation time between counter-propagating laser beams traveling in opposite directions in closed or open optical paths.
These gyroscopes exploit the physics of the Sagnac effect. For applications requiring very high performance, the ring laser gyroscope is currently more diffused and has a bigger market share.
But for marine vessels, gyroscopes need to consider two control methods, passive and active control.
When it comes to passive control, the control system does not require external power. Many passive control systems function as bilge keels and sloshing. Some types are only active control through systems like rotating cylinders. But a combination of both is the most useful. Internal and external system control types also play a major role when it comes to stabilization.
External control systems will generate resisting load (that’s different forces and moments) outside of the vessel’s hull while internal systems generate resisting loads from within.
Internal systems reduce or eliminate hydrodynamic drag but create a volume penalty for a vessel. External systems are lightweight but it also creates hydrodynamic drag and this is coupled with ineffective at zero forward speed.
A gyro-stabilizer system has to use resisting moments. These moments are the cross-product between the angular momentum vector of the flywheel and the angular velocity vector around a precession axis.
The resisting moments are applied to resist external excitation moments and reduce roll.
How to Figure Out Motion
When it comes to designing ship roll gyros the designers need to know the wave loads the vessel faces, the ship’s motion (or even the ship model), and the actuator characteristics.
Non-linear systems were chosen as the best representation of stabilization.
Non-linearity Analysis of Ship Roll Gyro-stabilizer Control System looks at a non-linear system modeling of gyro-stabilizers since this look at all volumes of motion and can formulate a non-linear ship roll model that adds inertia, damping and restoring the term of the vessel
Today gyro-stabilizers are potentially lightweight with no hydrodynamics drag and effective at zero forward speed because non-linear systems in the gyro-stabilizer model give results that are closer to real situations on the water and what conditions vessels will deal with.
These correspond with the amplitudes and frequencies of gyroscopes that can become smaller and more cost-effective.
Keeping Boat Stability Simple and Easy
The Seakeeper 1 retails for $14,900 and can be installed in existing vessels within the length and weight they have been tested for.
The gyroscopic system weighs 165kg. Like other Seakeeper systems, the installation is simplified with new pre-filled, self-purging designs that have minimal scheduled maintenance because the system has heavy-duty gimbal shafts and bearings.
It is a fascinating system that diminishes roll motion.
References
Seakeeper, 2020. Seakeeper 1 Launches the smallest Seakeeper ever. [online] Available at: https://www.seakeeper.com/press-releases/seakeeper-1-launches-as-the-smallest-seakeeper-ever/ (Accessed August 2021)
Begovic, Ermina & Mancini, Simone. (2021). Stability and Seakeeping of Marine Vessels. Journal of Marine Science and Engineering. 9. 222. 10.3390/jmse9020222. Pongduang, Sathit & C, Chatchapol & Iamraksa, Phansak. (2021). Non-linearity Analysis of Ship Roll Gyro-stabilizer Control System. Sustainable Marine Structures. 3. 10.36956/sms.v3i1.316.
