The 5 most common marine fouling organisms and the effect they can have on your boat

Jun 21, 2023 | Antifouling Tips

Biofouling is a natural process that occurs when marine organisms attach themselves to surfaces that are submerged in the water, such as boat hulls. Whilst the diverse marine life is fascinating, these organisms can cause significant problems for boat owners who spend huge sums of money on paints and new technology to reduce the adhesion of this marine biofouling to their hulls. Furthermore, hull fouling can cause a huge impact to the marine environment where invasive species are introduced around ports and docks, upsetting the natural ecosystem – fouling communities can compete with native shellfish for food and other resources.

In this blog, we will explore the top five marine fouling organisms including barnacles, tube worms, and algae and discuss the detrimental effects they can have on your boat.

1. Barnacles

Barnacles are one of the most common and recognizable biofouling organisms found on boat hulls. These small, crustacean creatures attach themselves firmly to surfaces using a cement-like substance. As they multiply and grow, they form a hard shell-like structure that can greatly increase drag, impacting your boat’s performance and reducing fuel efficiency. The accumulation of barnacles creates drag, slowing down your vessel and increasing fuel consumption. En masse, the added weight can even affect stability and manoeuvrability, making it more challenging to control your boat.

2. Tube Worms

Another common fouling species in the tube worm. Also known as serpulids, these are another type of marine biological fouling organism that can cause problems for boat owners. These creatures secrete a rock-hard, calcareous tube around their bodies and attach themselves to submerged structures. Tube worms can form dense colonies, covering large areas of the boat hull. Over time, their tubes can cause physical damage, weakening the surface and potentially leading to corrosion. Additionally, the accumulated tube worm colonies contribute to increased drag, resulting in decreased speed and fuel efficiency.

3. Algae

Algae are a diverse group of microscopic photosynthetic organisms that can thrive in many aquatic environments, including the surfaces of boat hulls. They often appear as a slimy green due to the presence of chlorophyll (but brown algae and red algae also exist) and cling to the boat’s exterior, turning darker when they dry out. Whilst small amounts of algae may not cause significant harm, their rapid growth can lead to several issues:

  • The increased roughness of the hull can reduce speed and fuel efficiency.
  • Algae can retain moisture, promoting the growth of other organisms and potentially leading to corrosion.
  • Algae are consumed by other aquatic organisms, including crustaceans such as mussels and barnacles which, in turn, adhere to the boat or ship hulls.
  • Excessive algae growth can obstruct intake valves, cooling systems, and other critical parts, causing engine overheating or failure.

4. Sea Squirts (Ascidians)

Sea squirts, also known as ascidians, are filter-feeding organisms that often attach themselves to solid surfaces such as boat hulls, pilings and other submerged structures. These gelatinous creatures form colonies and can spread rapidly when left unchecked.

While their appearance may not be as aesthetically displeasing as barnacles or algae, they can still cause significant problems. Sea squirts can obstruct water intakes, reducing cooling efficiency and potentially causing engine damage and their acidic excretions can contribute to surface degradation and paint erosion. Invasive ascidian species have also been reported to outcompete and smother a variety of native marine organisms including scallops, oysters and seaweeds.

5. Zebra Mussels

Zebra mussels, native to freshwater regions of Eurasia, have recently become a significant concern for boat owners in various parts of the world and are now classed as an invasive species in the UK, Ireland, USA, Italy, Sweden and Spain having been released into the waters by ships travelling across the world. They quickly colonise and disrupt the ecosystem, filtering out algae that native species need as well as attaching to and incapacitating native mussels.

These small, striped molluscs adhere tightly to hard surfaces, including boat hulls, propellers and water intake systems. Zebra mussels reproduce rapidly and can form dense clusters that can disrupt water flow, clog pipes, and damage equipment. Their sharp shells can also cause injuries to swimmers and reduce the resale value of the boat.

How to prevent marine biofouling

The settlement and growth of all of the fouling organisms mentioned above can depend on many different factors, some of which are out of our control such as; temperature, salinity of the water, levels of dissolved oxygen, nutrient availability and current flow. However there are a few factors that we, as boat owners, can have some degree of control over; whether there is any kind of antifouling system in place, how often the boat is used and how we store our boats when not in use can all have major impacts on fouling adhesion.

Use of antifouling technology

Traditionally, antifouling paints containing a biocide have been applied to boat hulls to kill off any marine organisms that attach to the hull. More and more, old-school antifouling paints are being replaced by new technology which uses fewer chemical substances and has far less detrimental environmental impact on the marine environment. This can include things like hydrophilic coatings, hydrophobic surfaces or, our area of expertise; ultrasonic antifouling.

Ultrasonic anti fouling systems

Our ultrasonic anti fouling system works using transducers attached to the inside of the boat hull (no drilling required) where they produce high frequency sound waves, far above anything humans can detect. These waves cause a slight vibration across the boat hull which produce tiny microcurrents around the hull which prevent organisms from attaching.

Using our ultrasonic antifouling systems to prevent the attachment of marine fouling to your boat’s hull not only benefits boat performance but also has an economic impact and helps prevent the transfer of invasive species around the world. Contact our team today to see how our range of ultrasonic antifouling products could help you.

By taking preventive measures and promptly addressing any fouling issues, boat owners can enjoy smoother sailing, improved performance and prolonged vessel longevity.