Passengers and crew traveling on yachts, ferries, cruise ships, workboats, tugboats, and offshore vessels always hope for a smooth ride in great weather, but this is, of course, a wish not always granted. If you've ever been tossed around on a boat and felt seasick, you recognize the need for a system that stabilizes your vessel. Seasickness is perhaps the worst effect of a rolling, unstable boat, but it's not the only one. Under challenging conditions, it can be challenging to move around the ship, and you might find yourself caught between plates and cups being smashed due to heavy rolls. This dramatically reduces onboard security.
Rolling is the most significant problem among all the motions at sea. Hence, solving the physical challenges of roll is a priority. Technological advancements in ship design have already given naval architects a chance to study wave motions around the hull of the ship. This provides a great foundation to create a design that minimizes such effects and ensures a safe and comfortable voyage for passengers and crew.
For workboats operating in rough conditions, an active stabilization system can be the decisive factor between getting the job done safely or not at all. A stabilized vessel improves the seamen's safety and comfort significantly, as boat roll is almost completely eliminated, both underway and at anchor.
Marine stabilization systems have become big business. Today you can choose between several providers, using various methods to decrease roll. Roll motion stabilization can be achieved in conventional ships by changing the form of the hull. Reduction in roll amplitudes is also possible by other means. Broadly, we classify stabilization systems in two categories:
On this page, we will primarily focus on
When designing a new yacht, we recommend thinking carefully through the advantages and disadvantages of the various options when choosing technology. Start by asking yourself these questions:
Due to the bulky construction and costly assembly, active tanks are mainly used on large bulk carriers, tankers, and LNG carriers.
Gyro stabilizers can be fitted into smaller boats and are also used by large ships and carriers. In a large
Active fins are fitted outside the hull. Sensing the rolling motion of the ship, a gyro sensor sends a signal to the actuating system. This causes the fins to move in a direction that
The video below shows active fins and their impact on the hull's movement in 0,5-1 meter high waves at zero speed.
Professional yacht broker Jimmy Rogers has written this article summing up the pros and cons of fins and gyros.
Fin stabilizers come with the only system that can handle both cruising and "at anchor" use. The "at anchor" stabilization force determines the size of the fins. Larger fins provide higher stabilization force, but also create more drag. This equals higher fuel consumption, an element that is often decisive for most boat owners. Larger fins also mean that the internal components grow in size, making it more difficult to install them in an optimal position. This can result in negative side-effects like causing yaw (steering effects) and sway (side-way movements). Thus, the overall situation often results in a compromise in fin size, meaning most fast boats today do not have the stabilization their owners want.
The most advanced fins today have a much better force angle than the older flat fin systems, providing a lot less drag as they also create lift. The improved force angle reduces the unwanted side effects of yaw and
Whether you are planning to get stabilizers for a newly built vessel or a retrofit, you should be aware of some key factors. Firstly, you must make sure the hull covers the basic stabilization requirements, meaning it has to be prepared for the extra load and strain.
As a naval architect, you have the freedom to design the hull as you wish in relation to stiffness and rolling. If you are going to have a stabilization system onboard, you can plan for a softer hull. Normally, a softer hull means more rolling. With stabilizers, however, you should only comply with the minimum requirements. This will provide greater freedom and a more fuel-friendly hull.
With Side-Power's installation guide, it is easy to do the right measurements while on the drawing table.
John Maxey is the owner of a 78 feet long Fairline Squadron. In this video from 2011, he shares his experience with the Side-Power stabilizer system:
The Side-Power Vector fins™ improve the roll reduction efficiency by some 50% in "at anchor" mode, and 30% in cruising situations compared to flat fins. At the same time, they dramatically reduce undesired yaw and sway motions caused by active fins.
The vast benefits of efficiency and the reduced side-effects make them particularly ideal for today's modern, fast cruisers. Traditionally, standard fin stabilizers have not satisfied the desired roll reduction without causing too many side-effects. This is particularly true for light-weight cruisers below 20 meters. Due to their shorter roll time periods, they are particularly difficult to stabilize. The Vector fins™ unique advantages make them the preferred choice for smaller, fast boats, a market that previously lacked ideal overall solutions for both cruising and anchor stabilization.
A stabilizer system will cost about 2-4 % of the boat's total cost. Complete installation on a 70 feet long new motor yacht will cost around GBP 70.000. The price range of active fins is smaller than for gyros. Because the gyros weigh four times more than an active fin-system, you have to strengthen the hull and give up space for the two-ton gyro-box.
Be aware that you usually don't install fins on boats smaller than 50 feet. The gyros will fit in vessels as small as 30 feet. Both systems can be retrofit in a motor yacht, which is great news for a proud boat owner who will rather install a stabilizer system on his ten-year-old rolling lady than buying a new motor yacht.
The direct benefit of the stabilization systems is clear when it comes to comfort and safety aboard. Consequently, this allows usage of the vessel when it otherwise would have stayed in port. For
With several manufacturers on the market and various technical solutions available, it is worth doing some research to find the stabilisation system best suited for your vessel. Some systems claim to be better at anchor, while others claim they're better underway. The final choice often comes down to the boat owner's intended use of the vessel, the design or hull limitations, and whether it's for a new or retrofit boat.
This checklist of important features/performance points might be helpful in your considerations:
At Side-Power, we provide you with the best advice based on your actual use and need. We have our Vector fins™ as a preferred product, offering highly effective roll reduction at anchor and underway. You will have to make some compromises when you choose which stabilizer system to invest in - we aim to provide you with the best possible foundation for making that decision.
US Patent US9527556 – Australian Patent AU2013335369 – Patent pending PCT/NO2013/050067