14 Oct 2020
What is marine biofouling?
A natural phenomenon, marine biofouling refers to the undesirable accumulation of oceanic organisms such as algae, microorganisms and plants on the submerged surfaces of oceangoing vessels within moments of contacting the water.
The build-up of biofouling on the hull of a vessel can have major economic, environmental and ecological impacts on the world we live in.
The evolution of hull cleaning
For a brief time towards the end of the 20th century, hull coating using Tributyltin (TBT) was considered as a perfect solution for halting the development of harmful marine growths on ship’s hulls. It was used for its ability to prevent the accumulation of biofouling on vessel hulls.
However, studies on TBT products soon revealed that these coatings - which contain highly toxic tin and copper - caused damage to the central nervous and reproductive systems, bone structure, and the gastrointestinal tract of marine life. As a result, this coating was initially prohibited by the Marine Environment Protection Committee (MEPC) of the International Maritime Organisation (IMO) in 1998 and then banned by the IMO in 2003.
After TBT coating was banned by IMO, the shipping industry and paint manufacturers turned to find effective, environmentally friendly solutions. The first Remotely Operated Vehicle (ROV) with marine fouling capture technology was introduced in 2003 and ROV hull cleaning became an exciting and innovative alternative.
To support the ban on the use of toxic coatings on vessel hulls, the GloFouling Partnerships Project was formed. This strategy was aimed at providing practical measures to minimise the impact of transferring IAS (invasive aquatic species) via ships’ hull.
The impact of biofouling on vessel hulls
Accumulation of biofouling such as tubeworm or barnacles can impact the performance of speed logs, sonars and other hull-mounted sensors while promoting corrosion. The long-term build-up of fouling increases the frequency of a vessel’s dry-docking operations for further hull cleaning, additional anti-fouling coating replacement or even hull repair.
The impact of biofouling on ship operating costs
Resistance is one of the most important areas that has to be taken into account in ship hull development. Shipowners and operators spend significant time and money to mitigate the effects of biofouling on vessel performance. Over time, the accumulation of these invasive organisms on hulls can increase the drag of the vessel in turn causing the resistance of the ship to climb. As a result of the fouling drag, a higher power specification for propelling the ship at a given speed is needed, impacting fuel efficiency by up to 40%! This comes at a hefty price with fuel costs representing as much as 50-60% of total ship operating costs.
Higher fuel consumption also means an increase in air pollutants and greenhouse gas emissions, further damaging our already fragile climate.
The impact of biofouling on marine ecosystems
The problem of accumulated marine organisms on submerged surfaces in seawater, particularly on ships hulls, is an age-old issue posing a serious threat to marine ecosystems around the world. As vessels move from one port to the next, they run the risk of introducing IAS and unknown parasites into indigenous areas. These alien breeds can reproduce and spread autonomously, creating biological competition and environmental modification of local biodiversity, potentially causing their extinction.
Removing biofouling from vessel hulls
The IMO Biofouling Guidelines sparked the development of modern alternatives that contain less toxic properties. Although drydocking helped to control the introduction of invasive species, this method of combating biofouling continues to be incredibly time-consuming and expensive. With such detrimental economic and environmental impacts, ship operators and owners need to take proactive steps to mitigate the effects of biofouling without these powerful yet harmful coatings, and improve hull performance. Modern methods include:
Hull cleaning divers:
As an interim measure between drydocking , many ship operators and owners hire divers to inspect vessel hulls and remove biofouling. Unfortunately, the scrapers and scrubbers used by human divers damage expensive vessel antifouling coatings and harms the marine ecosystem by disposing of the removed fouling in the ocean. Divers are also unable to work during the night time and need favourable weather conditions to perform the task.
Manual hull-cleaning also poses immense physical risks and health hazards to the diver as they assess and clean submerged vessel surfaces.
Brush ROV Technology:
Although able to work through most conditions, mechanical brush ROV’s (remotely operated vehicles) use brush bristles that run the risk of removing around 10% - 30% of costly anti-fouling coatings and often do not use safe methods of disposal for the biofouling removed.
The green, safe solution
Unlike traditional hull cleaning methods, HullWiper’sinnovative ROV technology operates an adjustable high-pressure water jet system using saltwater as a medium, removing and capturing marine fouling while preserving a vessel’s top coating.
Here’s a closer look at the HullWiper difference:
Powered by a 37Kw electric motor, the ROV is designed to clean 1,000m2 per hour day or night and in most weather conditions. Efficient cleaning while cargo operations are underway eliminates the need for expensive downtime and extended port calls. HullWiper’s video and photographic capabilities provide instant imagery of a vessel’s hull and marine fouling condition during inspection.
Ports Covered: With operations bases in Dubai including key locations across the Middle East, Sweden, Norway, Denmark, Singapore, Spain, Egypt, Australia, Panama, and Mauritius, ship owners, and operators can proactively manage the effects of hull fouling on vessel hulls and reduce costs. Plans are in the pipeline for new locations including Sri Lanka, Korea, South Africa, Chile, and the Bahamas.
Fuel Savings Calculator
Check out our Fuel Savings Calculator to learn how much more efficient and cost effective your vessel could be with HullWiper technology
Visit www.hullwiper.co to find out more what we can do for your fleet or book your eco-friendly hull clean now. Not only will you get more bang for your buck but you’ll also be contributing towards a united, global eco-protective objective!
Image Source: gCaptain