Vessel stabilization systems, especially gyro stabilizers, have evolved dramatically over the past three years. New developments include smaller and more affordable units that are finding their way onto boats even under 30 feet. What once used to be a luxury reserved for large yachts is becoming a standard feature (or at least an option) on much smaller boats. Here’s how stabilization is shaping boating today.
What is stabilization and why does it matter?
Boating has changed, especially in how we define ease-of-use and comfort. Boats have become simpler to run and more laden with all kinds of amenities. In the quest for friendlier boating, and with up to 70% of first-time boaters getting seasick, stabilization systems are becoming necessary equipment for boats of all sizes.
Stabilization is done primarily in two ways – fins and gyros. Fins are active appendages that protrude from the hull and move back and forth to help keep the boat steady. Gyro stabilizers are spinning flywheels that work from inside the boat that exert pressure to dampen roll. Both systems have benefits and challenges.
Active fins are usually better as a stabilizing force under way rather than at rest. They alter their angle based on the rate of roll and oppose the wave force that produces a rolling motion. They work much like aircraft ailerons. To work efficiently, they must have water flowing over their surface, and at rest they act more like paddles than wings.
“Active” refers to the control mechanism that makes them move. The challenge with fins is to design them to minimize drag at high speed but maximize lifting area at rest, which are opposing dilemmas. There are many influencing factors on the size of fins including boat length, tonnage, and shape, and even the cruising area. For example, Long Atlantic swells will exert different forces than the short roll period of the Caribbean. Fin manufacturers like Quantum, WESMAR and Naiad are developing fins that are more active at rest but still reasonably quiet so they can run all night in an anchorage.
Gyroscopes are not new. They’ve been used for motion control on vessels since the beginning of the 1900s and they work on the principal of the conservation of angular momentum with a spinning flywheel “precessing,” which is keeping its rotating axis perpendicular to the torque that is being exerted on it. It takes considerable force to displace a spinning wheel and a gyro spinning at very high rpms wants to stay upright and will compensate for the motion of the boat. Traditionally, size, weight, power requirements and cost have given gyros limited practicality in the yachting market but that has made a dramatic turnaround in the last decade.
Gyros can be open-air or closed in a vacuum and the bearings are either water or air cooled. The new active gyros come in various sizes and therefore strengths and have active control mechanisms that monitor bearing and motor temperatures, vacuum pressure, gimbal angles and more. It’s best to mount them low in the hull aft of midship and although it’s ideal to install them on the centerline, it’s not necessary, which is why larger boats can use two or more gyros simultaneously. They come in some form of enclosure and a cradle usually made of cast aluminum. They also have a noise and vibration shield because they do tend to hum once in operation.
A flywheel spinning at 8000 rpm generates a powerful righting force so boats have to be reinforced to carry one onboard. Major players include Seakeeper, Quick Gyro, Veem and Mitsubishi. These companies have different strengths and focus points ut most are attepting on bring this technology to smaller and outboard-driven vessels like center console fishing boats from Skeeter, Jupiter, Regulator and others in the 30-foot and below segment where the majority of boaters live.
Seakeeper gyros tout a roll reduction of 90-95% at rest, which is where they do their best work. Targeting center console boats, the company has made gyros more efficient for vessels with a narrower beam, a deeper deadrise and therefore a shorter roll period. The company has even designed a module where the gyro is contained below the center seat/leaning post. This makes it easier for builders to incorporate the gyro into their new designs. The units have also had to become quieter due to their new proximity to the operator.
Power requirements and energy consumption
Stabilization without large AC generators was a fantasy just a few years ago but that’s changing too. Because Seakeeper now works with many manufacturers of small fishing boats, their gyros have to be powered by outboards. The small SK3 has a flywheel that spins three times faster but is only two thirds the size with half the power requirements than the next size up. It’s perfect for outboard boats where there’s typically no genset aboard. It’s best to spin up the gyro while on shore power, which takes only 35 minutes. Then a gyro can run off an alternator or one additional house battery. One battery weighs much less than a genset and is smaller so it saves room and fuel. There’s also an automatic cutoff for the gyro after four hours if the battery bank drops.
Quick Gyro’s air-cooled systems need no thru-hull for a water source and are available in sizes for boats 22-100 feet. The company is working on DC-powered models that are coming soon. Veem builds units primarily for superyachts while Mitsubishi’s Tohmei Anti Rolling Gyro is now manufactured by Mohmei and also comes in varying sizes.
Can gyros be retrofitted?
The concept of refitting existing vessels with new stabilization technology is particularly challenging when you consider space constraints, power restrictions and that pesky already-installed equipment that gets in the way. Take heart though, some of the new products challenge all our refit assumptions especially in terms of size and the onboard real estate required to shoehorn them in.
For example, the newly launched Seakeeper 1 is designed for boats 23-28 feet and features a flush-mount design that completely contains the unit, leaving no part of the sphere hanging below the point of installation. This design makes installs easier and faster for refits and new boats alike. The brake system on the Seakeeper 1 is completely hose-less and uses a single cylinder, making it replaceable in the field to save time and cost. The smallest of the company’s systems can be integrated with Garmin, Simrad and Raymarine MFDs, or with its own 5-inch touch display to deliver operator information.
The Seakeeper 1 relies solely on 12v DC power and draws only 55 amps. The steel flywheel spools up in 21 minutes and it’s 35% smaller and 15% lighter than the next largest model. As an idea of pricing, this model comes in at just under $15,000.
Smaller units from Seakeeper and Quick Gyro will fit just anywhere and the structural reinforcement isn’t as massive or invasive as before so a refit is more plug-and-play. About 25% of gyro business is in refits.
Huge progress has been made in the technology in a very short time but you can bet stabilization systems aren’t done evolving. Most manufacturers have a two-pronged strategy for the future: First, they expect to add incremental performance improvements to existing units so they’re quieter and less power hungry and will be able to run for eight hours on battery power alone and therefore overnight without the noise of a genset. Second, the companies continue targeting smaller boats including runabouts down to 20 feet and even towing sport boats, so the entirety of the boating market will benefit from the trickle-down technology and lower prices.
A steadier boat is a safer boat. Crew and cargo stay put. The boat works less so things break less. Anglers can fish longer and divers can board safely. People are less fatigued at the end of the day and sleep better at night, and a rested crew makes better decisions, not to mention is more pleasant to be around. And if your significant other won’t set foot on the boat if it isn’t tied to the dock due to seasickness, stabilization systems aren’t really “optional,” are they?
Frequently Asked Questions
What is gyroscopic stabilization?
Gyroscopic stabilization is the reduction of rolling movement on a boat or yacht at sea. Stabilization is achieved through the use of a gyroscope that senses the orientation of the vessel and automatically apples force to counteract the rotation and roll.
How does ship stabilization work?
A gyro stabilizer on a boat senses rolling movement and motion and counteracts that movement through the production of torque (i.e. applying measured pressure and weight). Gyroscopic stabilization systems can use electric sensors, motorservos and/or mechanically-operated gyroscopic counter-weights to record, communicate and react to movements at sea, resulting in increased rotational stability.
When were boat stabilizers invented?
Ship stabilizing gyroscopes were first invented in the 19th century and the technology has evolved in recent years to be able to be installed on smaller boats and yachts as well as larger ocean-going ships and vessels. Modern boat equipment manufacturers such as Seakeeper have developed smaller, innovative new roll stabilization systems for motor yachs and recreational vessels. The first large ship to use gyroscopic stabiization was the USS Henderson in 1917.
Driving a launch around a harbor with over 1,200 moorings gets you acquainted with many kinds of boats....