For Cathelco, the DragGone system began as an internal “CleanShip” initiative: a practical idea with a clear goal, reduce hull and propeller drag in a way that translates into lower fuel consumption, fewer emissions, and reduced risk of transferring invasive species. Like most new systems, the journey from first principles to repeat installations wasn’t a straight line. It was a development path with setbacks, breakthroughs, and a growing sense of confidence as testing, customer feedback, and independent verification began to align. 

Proving the principle: guided waves and heterodyning 

In the earliest stage, the team focused on answering a simple but critical question: can we reliably deliver energy where it needs to go to influence the fouling and drag mechanisms we’re targeting, without creating unintended side effects for the vessel or its surroundings? That meant structured testing to verify the underlying concept, including work around guided wave behaviour and heterodyning effects. These weren’t “marketing terms” in a slide deck; they were engineering realities that had to be measured, repeated, and understood. Early trials helped define what was feasible, what needed refinement, and what assumptions had to be challenged before anything could be taken from a bench environment to a ship. 

In-house prototypes: homemade, hands-on, and honest 

With the principle established, progress depended on getting practical. Much of the early product development happened in-house, where “prototype” really did mean homemade: built, modified, stripped down, and rebuilt again. Some iterations worked immediately; others failed in ways that were frustrating at the time but invaluable in hindsight. Each failure revealed something: a limitation in mounting approach, an unexpected interaction with materials, a performance constraint, or a reliability issue that could become critical offshore. That cycle of trial, learning, and redesign is what turned a promising concept into a system robust enough for marine conditions and maintainable by crews who need equipment to be dependable, not delicate. 

The first real-world milestone: installation in Canada 

A defining moment in the DragGone story was the first installation, completed in Canada. That step matters because shipboard reality is the ultimate test environment: space is limited, schedules are fixed, access can be challenging, and the system must integrate safely with existing operations. Commissioning the first unit highlighted where installation guidance needed tightening, what onboard stakeholders cared about most, and how the technology behaved over time rather than just during short trials. The lessons from that first project fed directly back into design improvements and helped establish the installation and operational expectations that later customers would depend on. 

Independent verification and environmental considerations 

As the system matured, third-party testing became an essential part of proving performance and building confidence beyond internal results. Independent verification is especially valuable in the marine sector, where operators need to justify decisions with evidence and where performance claims must stand up to scrutiny. Alongside technical validation, the team also considered underwater noise and broader environmental effects. That meant asking not only “does it work?” But also “does it do so responsibly?” Designing with the environment in mind, particularly in relation to underwater acoustics, helped ensure that the technology aligns with the industry’s increasing focus on sustainability and operational stewardship. 

Designing for the shipyard: safety, practicality, and installability 

Another key strand of development was refining the product so it could be installed safely and consistently across different vessel types. A system can perform exceptionally in controlled conditions but still struggle in the market if it is difficult to fit, risky to handle, or complicated to maintain. Product enhancements therefore focused on practical engineering details: improving mounting concepts, simplifying installation steps, strengthening protection where needed, and ensuring the system works with shipyard realities. These refinements are often less visible than the “core technology,” but they are what make the difference between a one-off trial and a solution that can be deployed repeatedly with confidence. 

Customer collaboration: fitting the system to real operations 

From early on, customer engagement wasn’t treated as a final sales step, it was part of the engineering process. Working directly with operators helped clarify vessel-specific requirements and constraints, so Cathelco could propose a configuration that suited each customer rather than forcing a one-size-fits-all approach. The objective was always to avoid disruption to operational conditions while still achieving maximum results. When the system is properly matched to the vessel and its operating profile, the benefits stack up: reduced fuel consumption, lower emissions, and a meaningful contribution to limiting the transfer of invasive species associated with fouling and marine growth. 

From ups and downs to repeat business 

Looking back, the path from the initial CleanShip project to a finished product installed on multiple vessel types reflects the reality of innovation: progress comes with ups and downs. There were moments when prototype results forced a rethink, where installation learning demanded redesign, and where verification raised new questions to answer. But there were also breakthroughs. Those points where data, onboard experience, and operator feedback all confirmed that the technology was delivering meaningful value. Few things match the sense of achievement that comes from seeing strong results in service and hearing directly from customers that the system is doing what it was designed to do. 

What comes next: niche applications, propellers, and beyond marine 

The most exciting part of developing a technology like DragGone is that “launch” is rarely the end of the story. The team continues to look for ways to improve performance, simplify installation, and widen the range of vessel types and operating profiles the system can support. That forward momentum is driven by the same approach that shaped the early CleanShip work: measure carefully, learn quickly, and iterate with purpose. 

There is also growing interest in adapting the technology for niche areas and propellers, applications where geometry, access, and operating conditions can be very different from typical installations. And while shipping remains the core focus, the underlying principles may prove relevant in adjacent industries where surface condition and efficiency matter. For Cathelco, that’s the long-term value of rigorous R&D: it produces a solution that not only works today, but can keep evolving, helping customers cut fuel and emissions, protect performance, and operate more sustainably for years to come. 

Where it started

Our first Marine Growth Prevention System was installed in 1963 on a Royal Navy submarine. The principle behind it is electrolysis: copper and aluminium anodes prevent marine organisms from colonising seawater pipework while suppressing corrosion. The science has not changed. What has evolved is the technology around it, from panels to controls to digital capability.

Over the following decades, MGPS and ICCP became an industry standard. Our systems are now installed on more than 20,000 vessels worldwide, across commercial shipping, offshore, naval, and leisure marine sectors. We operate from offices in the UK, India, the Middle East, and Singapore, supported by a distribution and service network spanning more than 40 locations.

What has kept us here

Less than 1% of the systems we supply fail. That is a track record built on engineering rigour, consistent service, and a team that understands what vessel operators actually need.

People really collaborate to get the job done. Whatever the barrier, whatever the customer need, people will get it done. The seemingly impossible is possible.”

Customers come to us because they trust the product and the people behind it. Our systems are so widely recognised that, as one colleague recently put it, “you say the word Cathelco and they already know.”

Since 2018, we have been part of the Evac Group, a Finland-based cleantech company. That partnership has brought new resources and a wider strategic perspective, while the core of what we do has stayed the same.

Broadening the portfolio

Our most significant recent development is USP DragGone™, a patented ultrasonic biofouling prevention system designed for hull protection. Every vessel with an MGPS system is also a candidate for hull protection, and DragGone™ is the only system on the market that uses Guided Wave and Heterodyning technologies to deliver broader frequency coverage and larger protection areas per transducer than conventional ultrasonic systems.

DragGone™ has been independently validated at the DHI Maritime Technology Evaluation Facility and is now installed across a range of vessel types, from superyachts and passenger ferries to bulk carriers and offshore support vessels. It has been recognised with the Technology of the Year award at the Maritime Decarbonisation Awards and the Innovation category at the Ship Technology Excellence Awards.

Where we are going next

The regulatory landscape around biofouling is tightening. The IMO’s focus on biofouling management continues to sharpen, and vessel operators are increasingly looking for practical, proven solutions that fit within evolving compliance frameworks.

We are investing in both our product range and our approach to market to make sure we remain a useful, accessible partner for the people navigating these changes.

What are Invasive Aquatic Species (IAS)? 

InInvasive aquatic species are organisms introduced outside their natural range into an aquatic environment. They can include plants, animals, algae, and microorganisms. Not all non native species become invasive, but some establish successfully, spread quickly, and cause ecological or economic harm.

Common pathways that support spread include:

Human activity
Recreational boating, fishing, aquaculture activities, and movement of marine equipment can unintentionally transport organisms into new environments.

Ballast water from ships
Ships take on ballast water in one region and discharge it in another. That process can move a wide range of organisms between ports. This pathway has historically been a major contributor to marine introductions, and regulatory requirements and improved ballast water management practices have reduced risk in many parts of the industry.

Ship hulls and niche areas
A ship’s hull is the largest submerged surface and can transport attached marine growth between ports and regions. Risk is often concentrated in niche areas such as sea chests, gratings and strainers, rudders, and thruster tunnels. These recessed and complex spaces are harder to access, inspect, and clean, which makes them more prone to biofouling accumulation. Biofouling transfer is increasingly addressed through guidance and regional requirements, and further regulatory development is expected in coming years.

In addition, in water cleaning without capture or containment can release removed biofouling and coating debris into the sea. Uncontained discharge is recognised as a potential pathway for IAS spread.

Climate change
As seawater temperatures change, conditions that previously limited certain species can shift. Warmer temperatures can increase the likelihood that some non native organisms survive and establish in new regions.

Why marine environments are vulnerable to invasion?

Many marine habitats are diverse and productive, but they can also be sensitive to disturbance. Introducing a single invasive species can create knock on effects across multiple trophic levels, particularly when the newcomer is a strong competitor, an effective predator, or alters the physical habitat.

Common and well known Invasive Aquatic Species affecting marine ecosystems

Below are examples frequently referenced in discussions on marine and coastal invasions and shipping related transfer pathways.

Zebra mussels

Zebra mussels are native to freshwater systems in parts of eastern Europe and western Asia. They were introduced to North America in the 1980s through ballast water discharge and spread rapidly by attaching to boats and equipment moving between waterways. Zebra mussels filter large volumes of water, which can increase water clarity. At the same time, filtration can reduce phytoplankton availability for native species. They also form dense colonies and often outcompete native mussels and other bivalves for space and resources.

European green crab

European green crabs originate from the northeast Atlantic and have been introduced to new coastlines through shipping related transport, including ballast water. Once established, they can spread along coasts through natural movement and additional transport on vessels and marine equipment. They prey on native shellfish such as clams and oysters and compete with native crabs for food and habitat. Their burrowing behaviour can disturb sediments and damage eelgrass beds, which are important habitats for many coastal species.

Lionfish

Lionfish are native to the Indo Pacific and were introduced to the western Atlantic largely through the release or escape of aquarium kept species. After introduction, they spread rapidly as larvae disperse with ocean currents. Lionfish are effective predators that feed on a wide range of reef fish, which can reduce native fish populations and alter reef community composition.

Asian shore crab

Asian shore crabs were first recorded on the US east coast in the 1980s. Their introduction is commonly linked to shipping related pathways such as ballast water and stowaway transport on vessels or cargo. They can spread further through coastal movement and repeated transport between ports. Asian shore crabs compete with native crabs for food and shelter and can reach high densities in suitable habitats. They also prey on native molluscs, adding pressure to local shoreline ecosystems.

Caulerpa seaweed

Caulerpa species have spread outside their native range through the release or escape of aquarium kept organisms and through fragment transfer on anchors, fishing gear, diving equipment, and marine infrastructure. Because some Caulerpa can regrow from small fragments, even minor breakage can contribute to new outbreaks. Caulerpa can form dense mats that crowd out native seagrass and algae, reducing habitat quality for species that depend on those environments. Over time, this can change the structure of the seabed habitat and the communities that live there.

The impact of Invasive Aquatic Species 

IAS introductions are not only a conservation issue. They can affect coastal infrastructure, fisheries, tourism, and vessel and port operations. Impacts vary by species and location, but the patterns below are common.

Competition with native species 

Many invasive species compete directly with native organisms for food, space, and habitat. When an invasive species has fewer predators, higher reproduction rates, or broader environmental tolerance, it can gain a strong advantage.

European green crab is a widely cited example because it preys on shellfish and competes with native crabs. In areas where populations establish, local shellfish beds can be affected, with consequences for ecosystems and fisheries.

Research from the Journal of Fish Biology shows that competition can also destabilize local communities. As habitats degrade and resources become more limited, pressure increases across the food web. In some cases, less competitive species are displaced from key habitats, reducing overall biodiversity.

Habitat degradation 

Some IAS alter the physical or chemical conditions of habitats, which can create long term changes in ecosystem structure.

Zebra mussels, for example, can alter aquatic systems by filtering phytoplankton, shifting nutrient pathways, and changing the conditions that support native fish and invertebrates. On reefs, invasive predators such as lionfish can reduce herbivorous fish populations that help control algal growth. That can indirectly contribute to reef degradation, especially where reefs are already stressed by global warming, pollution, and/or overfishing.

Economic impacts 

The economic cost of IAS can be significant, particularly where invasive organisms affect fisheries, tourism, and infrastructure.

European green crab can threaten shellfish industries because commercially important species are part of its diet. Fouling organisms can also create operational problems. Zebra mussels are a well known example due to their ability to colonize and clog pipes and water intake systems on ships, increasing maintenance and cleaning requirements. Overall, invasive aquatic species damage is estimated at $120 billion annually in the US alone.

In shipping, biofouling that carries IAS increases drag and can reduce hydrodynamic performance, contributing to higher fuel consumption and emissions. For vessel operators, that creates a combined cost and compliance challenge.

Cascading impacts through marine food chains 

IAS can disrupt established ecological relationships. Invasive predators may reduce prey populations directly and also compete with native predators for food. Over time, these changes can shift which species dominate an ecosystem and how energy moves through the food chain.

How to prevent the spread of Aquatic Invasive Species 

Reducing IAS transfer risk requires a practical, multi-layer approach that combines operational controls with prevention technologies. The most effective programmes focus on stopping organisms from establishing in the first place and reducing the likelihood of release during maintenance activities.

Key prevention strategies

Manage biofouling in niche areas
Niche areas are often higher risk because they provide shelter from flow and are more difficult to inspect and clean. Marine growth prevention systems (MGPS) can help reduce fouling build up in seawater intakes and internal seawater systems. By using niche area mounted anodes to control conditions that support settlement and growth, MGPS can reduce the likelihood that organisms establish and are transported between regions.

Reduce hull biofouling to limit transfer risk
Ultrasonic antifouling systems use high frequency sound to create micro vibrations in the structure, which can make it harder for fouling to establish on treated surfaces. This approach can support hull cleanliness between maintenance windows and reduce drag build up over time.

Cathelco’s DragGone is an example of an ultrasonic antifouling system designed to support hull performance and efficiency. By helping to limit fouling accumulation, ultrasonic systems can also reduce reliance on frequent reactive cleaning and support broader biofouling management planning.

Use responsible in water cleaning practices
If in water cleaning is used, capture and containment can reduce the risk of releasing living organisms and coating debris into the surrounding environment. This is increasingly important for invasive species control and for local environmental requirements.

Control measures that support long term management

Biofouling management plans (BMP)
Many jurisdictions require ships to maintain a documented plan that outlines inspection routines, maintenance schedules, and cleaning procedures.

Biofouling record books
Keeping clear records of inspections, cleaning events, and actions taken helps demonstrate due diligence and supports operational consistency across voyages.

Protect your vessels from invasive aquatic species

Unchecked invasive aquatic species can disrupt ecosystems, affect fisheries, and increase operational costs in shipping. Prevention is most effective when it is proactive and practical, combining good housekeeping with technologies that reduce the likelihood of fouling establishment in the first place.

Cathelco supports operators with marine growth prevention systems for seawater intakes and internal seawater systems, and ultrasonic antifouling systems for hull performance support. If you would like to discuss biofouling risk reduction for your vessel type and trading profile, speak with our team.

Consult experts today to learn how Cathelco’s advanced technologies can help you deal with aquatic invasive species. 

One common method used to protect the hull is sacrificial anodes. These are shaped metal blocks attached to the hull that are designed to corrode in preference to the hull steel, reducing the rate of hull corrosion. 

The limitation is that sacrificial anodes are consumable and must be replaced as they wear away. In addition, once installed, their performance is largely determined by the anode material, the number and size of anodes, and the water conditions in which the vessel operates. They cannot be adjusted day to day. 

For this reason, most operators choose impressed current cathodic protection (ICCP) instead, or together with sacrificial anodes. ICCP uses powered anodes and reference electrodes to monitor the electrical potential at the hull/seawater interface and automatically adjust electrical output to maintain the appropriate level of hull protection as conditions change. 

Let’s explore what a sacrificial anode is, how it works, and why ICCP systems can be a better alternative. 

What is a sacrificial anode? 

Sacrificial anodes are devices designed to prevent the corrosion of metal surfaces, especially those exposed to electrolytes like seawater. The term itself is self-explanatory. These anodes create a galvanic anode cell, where the anode “sacrifices” itself to protect the cathode from galvanic corrosion. 

Sacrificial anodes consist of more reactive metals, which means they corrode preferentially, thereby sparing the less reactive materials they attach to. This way, they maintain the functionality of marine equipment and ensure a longer (and corrosion-free) lifespan for more important metals of ships and underwater structures.  

Besides ships and underwater structures, sacrificial anodes also work wonders in preventing corrosion in water heaters, pipelines, and tanks. 

In water heaters, the sacrificial anode is the metal rod that prevents the tank from corroding and eventually corrodes itself. The same is the case with both above-ground and underground tanks.  

How do sacrificial anodes work? 

Sacrificial anodes work through a galvanic (electrochemical) redox process: oxidation happens at the anode, while reduction reactions occur on the protected metal surface. 

When a sacrificial anode is electrically connected to a metal structure (like a steel hull) in seawater, the two metals and the seawater form a galvanic cell. The anode becomes the active metal and the hull becomes the cathode. Electrons released as the anode corrodes flow to the hull, keeping the hull surface cathodic and suppressing its corrosion. 

Simply put, the sacrificial anode corrodes instead of the hull. 

So how does a sacrificial anode prevent corrosion? It comes down to the natural electrochemical difference between the two metals. Sacrificial anodes are made from metals with a more negative electrochemical potential than the metal they’re protecting, so they preferentially oxidize and “take the hit” first.  

What are anodes made of? 

Sacrificial anodes are typically made from zinc, aluminium, or magnesium alloys. These alloys are more anodic (more active) than steel, so they corrode preferentially and protect the structure. 

Between the two main seawater options, aluminium anodes are widely used and can be cost-effective because they typically have a lower consumption rate than zinc for an equivalent protection requirement. Zinc anodes are also widely used in marine service and remain a common, proven choice for seawater protection. 

What are the disadvantages of sacrificial anodes? 

While sacrificial anodes work great, they do have their own set of limitations. These limitations can affect their overall performance and lifespan, making them unsuitable for certain applications. 

Short lifespan 

One of the main drawbacks of sacrificial anodes is their short and often unpredictable lifespan. Depending on the material and environmental conditions (like seawater temperature), they may need replacement in as little as six months. 

High chloride levels in seawater can also reduce the effectiveness and lifespan of sacrificial anodes. That rapid degradation means they need to be replaced frequently, which can be time-consuming and costly. 

Limited current output 

Sacrificial anodes also have limited current output. The amount of current an anode can produce is directly proportional to its weight. On larger ships, that can be a big issue as the demand for current capacity may exceed what the anode can realistically supply without adding excess weight. 

That means sacrificial anodes aren’t always suitable for large metal structures or those that require high current output. 

Hard to replace 

Replacing sacrificial anodes can be difficult, especially in hard-to-reach locations. 

For example, while the vessel is underway you will not be able to easily access the anodes for replacement. Even if you can, the process can be time-consuming and involves divers performing surface preparation and underwater welding. That adds to the maintenance burden and increases operational costs due to the need for additional labor. 

The benefits of ICCP systems over sacrificial anodes 

Unlike sacrificial anodes, ICCP systems have better control and performance, and more precise current control. This means optimal corrosion protection even with changing seawater conditions like temperature and salinity. 

Here are more benefits of ICCP systems: 

Longer life 

ICCP systems use inert anodes powered by an external current source, so they don’t corrode like sacrificial anodes. 

While sacrificial systems typically need replacement every 1 to 3 years, ICCP systems can operate for much longer, up to 15 years. This reduces maintenance, drydock time, and long-term costs. 

That alone makes ICCP systems a better option for long-term corrosion protection. 

Adaptability to complex structures 

ICCP systems require fewer anodes and provide precise current control, unlike sacrificial anodes, which rely on mass to generate protective current. This makes ICCP ideal for large or complex hulls. 

The system adjusts automatically to changing seawater conditions, delivers even protection, and can be maintained without drydocking, saving both time and resources. 

Sacrificial anodes usually struggle to provide even protection due to “shading” effects. Meanwhile, impressed current cathodic protection systems can be custom designed to meet the specific needs of complex structures. This enables them to prevent corrosion more effectively than traditional methods. 
 
In short, ICCP systems are highly adaptable to complex structures, making them ideal for offshore platforms and large vessels with complicated hull forms. 

Lower lifecycle cost 

Although ICCP systems typically cost more upfront, that’s because you’re buying an active, monitored protection system, not just metal anodes. A typical ICCP package includes a control panel (power/control unit) plus hull-mounted anodes and reference electrodes that continuously measure hull potential and automatically raise or lower anode output to maintain the optimum level of protection. 

Over the long term, that added equipment delivers value through more precisely controlled protection and long service life (for example, Cathelco’s flush-mounted ICCP anodes have a design life of around 15 years, far longer than sacrificial anodes). 

If you want to keep your ship corrosion-free and within budget, ICCP systems are a good investment. You can reduce operational expenditure on replacements and maintenance. 

Upgrade to ICCP with Cathelco 

ICCP technology is designed to reduce maintenance costs by protecting ship hulls and offshore structures from corrosion. Using hull-mounted anodes and reference electrodes, the system monitors hull potential and automatically adjusts current output to maintain the right level of protection as conditions change.

If you’re evaluating ICCP for your fleet or newbuilds, you can explore the options and specifications in our materials: view the product catalog online, or download the Cathelco ICCP brochure for a clear overview of system configurations and components.

Why coverage gaps matter

There is a simple reality behind hull biofouling management: you do not need a fully fouled hull to lose performance. Localized fouling will still add drag, and drag translates quickly into higher fuel consumption and higher emissions.

The practical constraint on large vessels

For ultrasonic antifouling, achieving strong results starts with one practical requirement: being able to place transducers where they are needed to treat the entire waterside of the hull. On many large commercial vessels, that has not always been straightforward.

Large sections of the inner hull sit inside ballast tanks and other wet spaces, and traditional transducer installations require a dry environment. The result is that some ships have faced unavoidable coverage compromises, leaving parts of the waterside hull outside the treated area.

The solution: waterproof transducer installations in wet spaces

Cathelco has introduced a new cofferdam add-on to address that limitation and expand where its ultrasonic antifouling systems can be installed on large commercial vessels.

This enables installations in wet areas such as ballast tanks, bilges and other wet spaces. This in turn means transducer placement can be planned for the entire hull, rather than being dictated by where dry inner hull access happens to be available.

How the cofferdam works

The cofferdam itself is a steel housing welded to the inner hull at the planned transducer location. The transducer is mounted inside the sealed chamber and secured with a lid to maintain watertight integrity. Cofferdams are specified only where needed, so projects can add waterproofing for the particular transducer locations that require wet-space installation.

Discuss your application

To request a quotation or discuss cofferdam applications for your vessel or project, speak with the Cathelco team. We can review your vessel arrangement, identify suitable transducer locations, and advise on where cofferdams may be needed to support broader hull coverage.