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Going 4 Performance: Introducing the Seakeeper 4, Seakeeper 4.5 and Seakeeper 40

Seakeeper offering new models and improvements to current model

LEESPORT, Pa. (August 14, 2023) – Seakeeper, the leader in marine motion control, has launched two new gyrostabilizer models, the Seakeeper 4 and Seakeeper 4.5, and performance improvements to a current model, now the Seakeeper 40.


The Seakeeper 4, for boats ~38-44 ft., and the Seakeeper 4.5, for boats ~40-46 ft., were designed to maximize angular momentum, or gyroscopic power, per cubic inch. Compared to the Seakeeper 3, the Seakeeper 4.5 offers 50% more gyroscopic power.

In terms of physical footprint, the models are 7% smaller and can fit into the same space as the Seakeeper 3, making the Seakeeper 4 a viable trade-in and upgrade option. The Seakeeper 4.5 fills the gap in the current model lineup for boats with generators, offering an option that’s 30% smaller than the current Seakeeper 5 and Seakeeper 6 models.

The two new models operate on the same platform but incorporate different motors, drives, and electronics to allow the Seakeeper 4 to operate on DC power and the Seakeeper 4.5 to run on AC power, giving boaters options based on whether their specific vessel has a generator onboard.

Additional features added to the latest models include:

The new flywheel design features a deeper, lower hemisphere, enabling the motor to be tucked inside the flywheel, reducing overall height, and providing the most efficient shape to maximize performance per pound and footprint.

The single-cylinder brake design saves space, weight, and enhances reliability by eliminating hoses and connections. It requires no annual service and incorporates redundant safety mechanisms.

With the choice of AC or DC power, those with or without a generator can take advantage of the latest model introduction.

Zinc-nickel plated components and the new single-cylinder brake design provide enhanced corrosion resistance.

The new units feature a control keypad and integrate with compatible MFDs, eliminating the need for a separate 5-inch display.

Fewer mounting bolts, greater access clearances, top cover fasteners to make service access faster and easier, and the ability to disassemble the frame make the new units faster and easier to install and service.

“When surveyed, our customers said the most important thing to them in a stabilizer is performance,” explains Seakeeper President & CEO Andrew Semprevivo. “So, that’s what we’ve prioritized. We’re constantly engineering new ways to deliver the greatest angular momentum in the smallest, lightest package possible.”

The latest model introductions incorporate the latest engineering advances into new mechanical designs from the ground-up, creating efficiencies in the amount of angular momentum per volume and weight. The Seakeeper 4 and Seakeeper 4.5 will be available for shipment in November 2023 and will retail for $44,800 and $52,600, respectively.


The Seakeeper 40 for boats 85 feet and up (up to 115 tons), engineered from the previous Seakeeper 35 model, launches with improved power density, meaning it has 5,000 N-m-s of angular momentum more than its predecessor. The additional performance comes without additional power draw, space requirements, and minimal weight increase.

“While new products are important,” said Seakeeper’s Vice President of Growth & Strategy Will Cimino, “we find it equally important to continuously improve current models by incorporating new technology and innovations. Performance is everything to our customers, and we want to continue to give them the most effective and efficient gyrostabilizers available.”

The Seakeeper 40 also features field replaceable bearings (FRB), an innovation offered on all current models Seakeeper 9 and above. FRB saves money for the end-user if service is required on the flywheel bearings.

Shipment of the Seakeeper 40 will begin in September 2023 and will retail for $324,800.

About Seakeeper

Founded in 2003, Seakeeper, Inc. is the leader in marine motion control, changing the boating experience by eliminating unwanted motions, and increasing comfort and safety onboard. Seakeeper, a gyrostabilizer for boats 23-200+ ft., eliminates up to 95% of boat roll, the rocking motion that causes seasickness, fatigue, and anxiety. The product launched in 2008 and is based in Leesport, Pennsylvania. Seakeeper Ride, a transom-mounted Vessel Attitude Control System (VACS), eliminates up to 70% of underway pitch and roll for boats 19-35 ft. It launched in 2022 and is based in Fort Myers, Florida. For more information, visit