Vessel Stabilizers

Vessel Stabilizers help to make life onboard more comfortable. I know everyone has succumbed at some point to boat motion in a seaway either rough condition or just a gentle roll. Eliminating roll can make your boating experience so much more enjoyable. There are several ways you can stop your boat rolling around either in chop or in waves, underway or at rest. Here are some ways;

We are looking here at SeaKeeper Gyro which is similar to the ARG Gyro. But first we look at the options available to a boater.

Stabilizing fins

active & passive

These fins counter roll by providing lift to oppose the boat roll. Passive fins just dampen roll with the drag of the fin, while active fins rotate, controlled by computers, to act like a rudder using the opposing force to counter to roll are to counter the roll. They can be quite expensive and also add drag and are susceptible to damage.

There are retractable and zero speed stabilizers


These are deployed on each side of the boat normally at the end of outriggers and the vanes reduce the roll by dampening the roll force.


The Nordhaven 47 BlueWater describes using paravanes when their stabilizers failed

Rocker Stoppers

Rocker stoppers are similar to Paravanes.

Gyro Stabilizer

Control Moment Gyro

The original Controlled moment gyro was developed in the early 1900s. These gyros were very heavy.

The latest form of this gyro is the ARG gyro developed by Mitsubishi and is used on Ferretti yachts.


SeaKeeper Gyro

This featured product looks at the SeaKeeper Gyro which is a Control Moment Gyro like the ARG Gyro.

From Seakeeper

Seakeeper is the world leader in active gyro stabilizer technology for the leisure yacht and commercial marine industry. Seakeeper’s gyro stabilizer systems:

Virtually eliminate zero and low speed boat roll, working at anchor and underway Require no through-hull cutting, eliminating the need for drag producing & damage-prone appendages Are small and lightweight, offering flexible installation options while consuming minimal power Provide yacht manufacturers & owners new heights of luxury and performance, offering the best in comfort and safety

What is Seakeeper Gyro 7000

The 7000 Gyro system is designed for boats 35-feet and up to 55ft.

SeaKeeper dampens rolling by tilting the gyro through the rams at angles determined by a the motion sensing computer.

Seakeeper Gyro uses a device known as a Control Moment Gyro. The gyro exerts a powerful righting force that smoothes out boat roll.

Like the control moment gyros used to position spacecraft since space is a vacuum, SeaKeeper uses a flywheel spinning in a vacuum.

SeaKeeper does come with a lofty price, with the Gyro 7000 costing $55,000 (plus installation costs). This is early days and costs could well be more affordable the concept is adopted en mass..

Seakeeper Gyro Technology (how it works)

We all know the spinning top theory. Spin it faster and the top will stand more upright, stop the spinning and the top falls over. The top when its spins fast enough takes on an axis from the center of the earth or perpendicular to a horizontal surface.

The SeaKeeper gyro is called a Controlled Moment Gyroscope. Inside the gyro is a spinning flywheel which like the spinning top analogy resists roll by trying to remain upright. The hydraulic arms then tilt the gyro fore and aft to transfer the gyroscopes energy to the boat.

The Seakeeper Gyro unit tilts fore and aft in its housing to control sideways (athwartship) roll. Gyroscopes control motion in the plane 90 degrees to the tilt of the gyro. The gyro sophisticated sensors determine the attitude of the boat and then make corrections using the energy stored in the gyro.


SeaKeeper Gyro in action

Seakeeper Gyro Video

This video demonstrates boat roll on this sports fisherman at zero speed.

Watch the gyro ball in the cockpit floor as it starts to move fore and aft and then see the boat roll smooth out.


This is an expensive option. However when you look at the total investment already made in a Motor Yacht the option makes more sense. You can enjoy your investment without resorting to seasickness patches.

Other factors come into account such as navigation. Imagine trying to use binoculars to see where you are, but cannot see because of a blurred image.

Safety is another concern. Seasickness or just a case of queasiness can drain strength from anyone.

The other advantage compared to vanes or fins is that there is no drag associated causing loss of fuel and performance