Vector Fins™ stabilizers

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Vector Fins™

Over the last few years, roll stabilization has become a must-have for boat owners due to the impressive increase in comfort it delivers. The dramatic roll reduction modern systems provide also increases safety on board and as a result, allows many families to get more use out of their boats.

What are yacht stabilizers
and how do they work?

Increased comfort on board


Increased safety
on board


Increased second hand boat value


Less overall fuel consumption

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What can stabilizers do for me and why do I need them?

As a captain, you surely have experienced the immense difference in onboard comfort on a calm day with a flat sea bed compared to even just a half-meter waves. It is the disruptive force of waves, which is the absolute worst enemy to boating.

Research shows that only 25% of the world's population is indifferent to seasickness. The rest of the population has various resistance but will become sick if exposed to waves above their threshold. With stabilizers installed, however, it's a different matter.

Rolling around at sea is something most people will prefer to avoid if they can. With the modern stabilizing systems available on the market today, they do reduce the risk of becoming seasick by 80-90 percent.

Another aspect worth considering is plain and simple onboard safety. Let's forget about seasickness and general onboard comfort for a while. A roll of just a few degrees impacts your footing onboard. Unexpected swells catch you off guard and send objects flying around. We've all been there. A stabilized boat is a very different base in terms of both perceived and actual safety.

It's like riding a magic carpet.

John Maxey, yacht owner

Introducing a revolutionary generation of fin stabilizers

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Vector fins™ is the only top-performing stabilizer system for both cruising and
at-anchor use. The fins' unique shape reduces drag and improves fuel efficiency, translating more of their power into actual roll stabilization.


The Vector Fins™, with so-called winglets similar to what you see on modern aircraft, will change the force vector closer to the vertical plane, resulting in far more effective stabilization and reducing the unwanted side-effects of yaw and sway significantly. With the force vector's improvement, smaller fins can achieve the same stabilization force, reducing the wet surface footprint considerably.

Another significant effect of the curved fins is that they create lift, reducing the hull's overall drag. In some high-speed yachts, the lift has offset the added drag completely, actually increasing top speed. The hydrodynamic lift generated by a fin is proportional to the square of its speed through the water, so a rise from say 17 knots to 24 knots would double the lift from the fins.


Vector Fins™ – a simple solution
to a complex problem!

The Vector Fins™ stabilizers dramatically improve the roll reduction efficiency while at the same time reducing undesired yaw and sway motions caused by active fins.

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The huge benefits both in efficiency and reduced side-effects is beneficial for all boat types. This is particularly important for today's modern, fast cruisers where traditional flat fin stabilizers have typically not been able to satisfy the desired roll reduction without causing too many side effects. The low weight and speed-efficient hull design cause short natural roll periods as well as it being easier to feel negative motions like sway and yaw in a lighter vessel. Also, these hull designs follow the waves more rigidly and thereby require more stabilization force to be applied faster due to the shorter roll periods. So to avoid negative sensations for the guests, it is important to apply forces in the right direction. This finally enables the use of fin stabilizers, getting all the benefits of a stabilization system that works well at "AnySpeed" also on smaller, lighter and faster vessels than what have traditionally chosen fin stabilizers.

The huge benefits in both efficiency and reduced side-effects are beneficial for all boat designs. This is particularly important for today's modern, fast cruisers where traditional flat fin stabilizers have typically not been able to satisfy the desired roll reduction without causing too many side effects.

The low weight and speed-efficient hull design cause short natural roll periods while being easier affected by sway and yaw motions. These hull designs follow the waves more rigidly and thereby require more stabilization force to be applied faster due to the shorter roll periods.

The Vector Fins™ can be up to 30% more efficient underway and up to 50% more efficient at anchor. Undesirable side-effects, as yaw and sway, can are reduced by up to 55%, compared to traditional flat fins.

< 55% less side effects than conventional
stabilizer systems

< 30% more efficient underway than flat fins


Unlike gyro stabilizers that always have the same maximum total force they can apply to reduce roll, independent of boat speed or roll periods, fin stabilizers increase their stabilization force by both speed and roll period when cruising.

Fin stabilizers increase the possible force they can apply by the physical law of all forces where speed is a factor, by speed, meaning a dramatic increase. Typically fin stabilizers do not totally utilize this potential because the forces become huge at higher speeds, so they are naturally limited by the force the actuator can apply to turn the fin to higher angles.

Fin stabilizers will also be able to apply a more total force to counter roll in a long roll period than in a short period. This is because it is the total force impulse over time that is important, and with the counter roll force being caused by the fin acting in an angle on the passing water, it can continue for an unlimited period.

The force impulse is named "Nms" - Newton x meter x second, so with the time factor being principally unlimited, so is the force impulse. This is a huge benefit because bigger waves are typically longer, so this is not just theory. While underway, Vector Fins TM typically improves the roll reduction efficiency by about 30% compared to standard flat fins of the same size.

Due to the Vector Fins™ unmatched efficiency, the system is accordingly capable of reducing the uncomfortable rolling motion of the boat up to 95% while cruising even in quite large waves, keeping you and your guests both comfortable and safe on board.

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< 50% more efficient at anchor than flat fins

At Anchor

Up to 50% more efficient than flat fin stabilizer systems. Spend those amazing nights at-anchor under the stars in a bay instead of in a busy harbor

As most boat owners spend more time at-anchor than underway, it is critical that the stabilization system performs well at any speed, including no speed.

A stabilized boat offers a significant increase in onboard well-being. Moving around, getting the tender out, serving dinner, or just getting in and out of the water for swimming becomes a lot easier and safer from a stabilized boat.

A good Any Speed stabilization system allows for comfortable use of your boat when you otherwise would, or at least should, have stayed in port.

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Verified stabilization test results

Princess 56 with 0.6m Vector Fins™

Cruising at 11 knots

At anchor

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No stabilizer

Vector fins™

Reduction of roll

Reduction of seasickness

Max roll movement

Max roll angle
















4.1 °

Average roll movement

Average roll angle

Virtually no loss of speed

The Vector Fins™ create as much lift as they add drag resulting in virtually no loss of speed, and thereby no added fuel cost.

Why are the Vector Fins™ so much better?

The Vector Fins™ simply re-direct the force direction/force vectors so that more of the force will benefit roll reduction and less force is wasted on the negative side-effects of yaw and sway that is unfavorable for a boat's handling and comfort on board.

The vertical concave shape of the fin creates a net force direction, both in cruising and in "At Anchor" situations, so the work is more "up/down" instead of side to side or almost horizontal, as flat fins work with forces parallel to the hull angle.

But there is more. By changing the net force angle, this also increases the leverage arm around the boat's rolling point, further increasing the physical forces that work on the boat to reduce roll. This provides a lot more roll stabilization per fin size, which means that drag, power consumption, internal space occupation as well as load on the mechanical parts is a lot less than with other fins that can give a similar roll reduction.

US Patent US9527556 -Australian Patent AU2013335369 - Patent pending PCT/NO2013/050067

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Vector Fins™ features

  • Up to 50% more efficient than flat fins
  • Up to 55% less side effects than flat fins
  • Advanced hydrodynamic fin design
  • 20% – 50% less resistance than other fins, results in > virtually no loss of speed and thereby no added fuel consumption
  • All fins are prepared for high efficiency in "Any Speed" – 2:1 size ratio, also "At Anchor"

The fins are made as a "one shot" vacuum injected vinylester process over pre-shaped core material in a closed mold method.

Designed with rowing and mat layers to ensure maximum strength and minimum weight. Can even withstand minor damages without totally disintegrating afterwards, unlike traditional production methods often allows.

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Up to

Up to
less side effects

  • Unlike a gyro, efficiency increases with speed

  • Minimal to no increase in fuel consumption
  • Minimal to no loss of speed
  • Silent all-night operation

  • Suitable for retrofit

Vector Fins™ benefits

Research & Development

In our focus to develop the best products for the marine market, we continuously invest to make all our products even better. We continually develop systems designed to integrate with existing and future technology. Many of the products we develop are designed for the large yacht and commercial industry however have perfect applications on all kinds of vessels.


Floating lab

58 feet test vessel with a top speed of 37 knots, fully loaded with advanced
sensors and logging facilities for data collection and analysis.

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Controller intelligence

  • Continuous development of the best control software possible, cooperating with leading companies in control technologies.

  • Color touch panel for ease of use and control.

  • Self adjusting - advanced algorithms - also "Any/No Speed" functions for stabilization at anchor.

  • Easy upgrade of software ensures future compatibility and improvements

  • Reverse gear position input, but also other sensors to safeguard that fins are centered and locked immediately if the boat is starting to move backwards.

  • GPS speed input (no shaft sensor) helps control algorithms do the best possible job.

  • S-Link™ integrates common intelligence with thruster systems and main hydraulics.

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SPS55 Actuator

The new SPS55 actuators for the Vector Fins™ are incredibly compact and silent, designed to fit in the small available spaces in modern boats below 20m/70ft where living space is strongly prioritized.

The SPS55 actuators have been designed to satisfy the needs of owner operated vessels with a total focus on reliability and hassle free operation, as well as ensuring a quiet operation as they will most likely be installed below the floor in living spaces.

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No moving hoses

Rack &
pinion drive connection

Symmetrically balanced

All external parts in stainless steel

Construction benefits

  • Squared base plate provides large load distribution area to hull while still being able to install in tight areas between stringers and bulkheads.

  • Dual, balanced cylinders provide symmetrical load and force.

  • The actuator can be installed in any direction in the boat, the fin angle is totally independent of actuator direction.

  • No moving hoses at all secures against leakages and potential wear, as well as making the installation easier.

  • Oversized bearings for lifetime operation with only a minimal level of maintenance.

  • Rack & pinion drive connection for quiet, reliable, long life operation, with very easy service when needed after thousands of operational hours.

  • Fins are installed and removed very easy and quickly from the outside for best convenience in for example transport or other haul-out situations where this might be needed.

                                                                                                                                                                                                                  • Defined shaft-shear point in case of the fins accidentally hitting something.

SPS66 / 92 / 93 Actuators

The height inside the boat is often the key measurement to allow for installation in modern boats. The SPS66 / SPS92 and SPS93 are typically 25% to 75% lower than others. Side-Power actuators for the Vector Fins TM are constructed for easy installation and minimal noise reproduction.

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All moving hydraulic connections are prefitted

Dual hydraulic cylinder setup for symmetrical

Non-moving  attachment points for hydraulic hoses

Lifetime lubricated high-end bearings, no need to grease bearings periodically

Construction benefits

  • Precision machining and assembly secures a long lifetime and durability.Dual, balanced cylinders provide symmetrical load and force.

  • No additional centre lock, this is automatic in the standard hydraulic system - very safe due to the hydraulics having extreme safety limits.

  • Dual cylinders provide:
    - Balanced load single cylinder solutions.
    - Less bearing load, thereby allowing for a more compact shaft bearing assembly.

  • Purpose-designed dual shaft sealing
    – superior to standard Simmer Ring lip seals.

  • Internal hydraulic connections on actuators are pre-fitted from factory, the installer only connects non­moving hoses/pipes - Easier and safer.

  • No complex adjustments required to set up controller with lots of factors, these are set automatically on first sea-trail the boat.

  • Defined shaft-shear point in case of the fins accidentally hitting something.

  • Most stabilizer systems require you to periodically service their bearings, meaning either a part change, lubrication and/or mechanical adjustments. Side-Power's latest generation of bearings do not need any of that, saving time and money for the owner with lifetime lubricated high-end bearings as standard, meaning one less service point on your vessel.

                                                                                                                                                                                                                  • Fins are installed and removed very easily and quickly from outside for best convenience in for example transport or other haul-out situations where this might be needed.

Standalone hydraulic power pack

The compact power packs can run the stabilizers from the generator power at all times. An optional load sense pump can also be added to allow for stabilization while underway and with the generator shut down.

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and easy
to install

This a complete hydraulic power unit (HPU) for installations where the vessel does not have a hydraulic thruster system. All of the hose and wire connections are pre-installed, allowing for faster system install and startup in the field. All connections are focused on two sides of the tank, allowing installation in confined spaces.

Sleipner offers similar pre-connected and easy-to-install central hydraulic systems when other hydraulic consumers, typically thrusters, are required. These have a similar level of integration while of course being a bit larger due to the higher capacities required by thruster systems. When combined with a hydraulic thruster system, the stabilizers and thrusters communicate via our S-link CAN-bus system, enabling automatic power distribution to where it is needed at the time, and even stabilizer control from the inexpensive thruster control panels.

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