Ultrasonic Antifouling: Could Sound Waves Change The Way We Protect Our Hulls?

Ultrasonic antifouling promises a different approach to managing marine growth, using high-frequency sound rather than relying solely on conventional coatings.

But how does it work, which boats is it suitable for and what should owners establish before investing?

For many boat owners, antifouling is an unavoidable part of ownership: lifting the boat, cleaning and inspecting the hull, then applying another coating.

Keeping marine growth under control matters. A fouled hull can affect speed, handling and fuel consumption, while growth around underwater fittings can create further problems. With the time, cost and environmental considerations involved, it is understandable that owners are exploring different approaches.

One attracting increasing attention is ultrasonic antifouling. Could it reduce marine growth and help owners get more life from their existing coatings?

How does ultrasonic antifouling work?

Ultrasonic systems use a controller connected to transducers, normally bonded inside the hull. Short pulses of high-frequency sound create tiny vibrations through the surface, aiming to discourage algae and other organisms from attaching. This form of antifouling is a preventative measure, not a cleaning system. It cannot remove barnacles or other growth already established and it must operate continuously while the boat is in the water.

Andreas Schulz, owner and CEO of BPS Marine, commented:

We use sound to help stop fouling. Transducers mounted inside the hull send ultrasonic waves through the surface, creating a microscopic layer of high pressure where the hull meets the water. This makes it harder for algae and barnacles to attach in the first place.

Our frequencies are designed to keep the hull clean without harming fish, whales or turtles. For us, protecting the ocean is just as important as helping owners save time and money. Less drag can mean lower fuel bills, while a cleaner hull can mean fewer haul-outs, diver visits and less maintenance. We have now completed more than 4,500 installations worldwide, from leisure boats and yachts to superyachts and commercial vessels - and that figure is growing daily.

Does it replace antifouling paint?

Not necessarily. Results can vary according to the boat, installation, water temperature, salinity, usage and severity of fouling in its home berth.

BPS recommends using its system alongside a suitable antifouling coating, although ultrasonic systems can also be used without conventional antifouling in some circumstances. The appropriate approach will depend on the boat, its construction and the conditions in which it is kept. When used with a coating, ultrasound becomes part of the wider hull-care plan, with the aim of reducing marine growth, limiting abrasive cleaning and extending the coating’s useful life.

Aaron Bunton, Sales and Marketing Director at Appex Trade, European importer of BPS Marine ultrasonic antifouling systems, explains:

Ultrasonic antifouling is about prevention. The system sends high-frequency pulses through the hull to help discourage marine growth from attaching. For owners, it may mean a cleaner hull, less frequent intervention and longer life from the coating already in place.

Regular hull inspections remain important, particularly around stern gear, drives, propellers, rudders, thrusters and intakes. Correct specification and transducer positioning are crucial because only surfaces reached effectively by the ultrasonic energy can be protected.

Is it suitable for every boat?

No antifouling system is universal. The number and position of transducers will depend on the boat's length, construction, underwater profile and equipment requiring protection.

BPS Marine says its systems are suitable for GRP, aluminium, steel and carbon fibre hulls, but not wooden boats. Sandwich construction, internal linings, inaccessible bilges and complex hull shapes can also influence installation, so the individual boat should be assessed rather than selecting a system by length alone.

Although normally bonded in place without drilling through the hull, this remains an onboard electrical installation. Power, cable routing, battery protection and interaction with other equipment must be properly considered.

What are the potential benefits?

On a suitable boat, a correctly specified system could mean:

Less accumulation of marine growth
Longer intervals between intensive cleaning and associated haul-outs
Less abrasive cleaning and potentially longer life from existing coatings
Better retention of hull performance and fuel efficiency between cleans

These are potential benefits, not guaranteed savings. Ask for evidence from comparable boats in similar waters and consider the cost against realistic lifting, cleaning, coating and power costs.

What about the environmental impact?

Many conventional coatings use biocides, while poor removal and cleaning practices can allow residues to enter the environment. The RYA encourages boaters to consider suitable alternatives and follow responsible maintenance practices.

Ultrasonic technology does not depend on biocides to create its effect, which makes it interesting. However, it would be premature to say that every system has no impact on marine life. Research is still developing, with some studies raising questions about underwater noise and marine mammals.

Owners should ask for independent evidence covering performance and environmental impact, including the operating frequencies and power levels of the system being considered.

Questions to ask before investing

Is it suitable for my exact hull material and construction?
How have the number and position of the transducers been calculated, and which surfaces will they protect?
Is there evidence from a comparable boat operating in similar waters?
What is the real-world power consumption and what happens if the battery voltage falls?
Should it be used with antifouling paint and what inspection schedule is recommended?
What do the warranty and independent environmental testing actually cover?

Part of the plan, not a fit-and-forget answer

Ultrasonic antifouling will not suit every boat, but when correctly specified and used as part of a considered hull-care plan, it could help reduce marine growth, preserve hull performance and extend the life of existing coatings.

Start with a clean hull, understand which areas the system will protect and continue with regular inspections. Most importantly, ask for evidence that reflects the type of boat you own and the conditions in which it is kept.

With BPS Marine systems only recently introduced to the UK market, evidence from boats operating in UK waters will be particularly valuable as the first installations complete a full season. As with any developing marine technology, understanding what the system can - and cannot - do is the starting point for an informed decision.