The commercial threat lurking below the waterline

The commercial threat lurking below the waterline
A ship that has heavy levels of fouling on it will be far less profitable, says Markus Hoffman

As owners and operators welcomed in a new era of capped fuel sulphur limits at the start of this year, with less catastrophic disruption than originally anticipated, a flurry of other challenges for passenger vessels in the form of the global Covid-19 pandemic was arriving to the shore. Throughout the entire industry, effective planning and foresight saw one of shipping’s many recent legislations to improve environmental impact come into effect relatively seamlessly.

Few could have predicted the disruptions and serious commercial consequences for passenger vessels in 2020 as global travel ground to a halt. The most visible sign of the disruption on the shipping industry has been the higher prevalence of idle vessels as the reality of four billion people going into lockdown and suffering travel restrictions struck and the passenger vessel sector was the worst hit.

Usually very active passenger vessels stopped as passenger numbers plummeted in the wake of travel restrictions, it was a very weird situation to see so many cruise ships and ferries docked with nowhere to go.

However, a huge risk to commercial buoyancy lies below the waterline: biofouling. Idle cruise and passenger ships, particularly those sat in warmer waters, are at significant risk of biofouling accumulation on the hull, with devastating impacts to fuel consumption when a vessel sets sail again.

Biofouling, especially macro or ‘hard’ fouling created by shell-forming creatures such as barnacles, is perhaps one of the most pervasive and destructive processes that can impact a vessel's earning potential.

The costs of biofouling manifest in many ways, and a ship that has heavy levels of fouling on it will be far less profitable than one with minimal or no hard fouling present. This is because it takes more fuel for a vessel with fouling to maintain the same speed through water as a vessel with no biofouling.

Hard fouling organisms in particular create huge added resistance, also known as hydrodynamic drag, on the hull as it sails through water. One commonly cited metric in the antifouling coatings industry hails from a 2007 study titled Effects of coating roughness and biofouling on ship resistance and powering by Michael Schultz, which states: “a vessel with 10 per cent barnacle coverage would need a 36 per cent shaft power increase to maintain the same speed.” Although this particular study was based on a naval frigate, the statistics are relatable to cargo and passenger ships too. Therefore, barnacles are creatures that you do not want to colonise the hull of your ship when profit margins are tight.

In 2019, I-Tech AB, developers of the antifouling agent Selektope, commissioned UK coatings consultants Safinah to undertake a detailed analysis of hard fouling data from dry dock inspection reports of all vessel types spanning 2015-2019.

The results of this deep dive into the data paints a worrying picture. Spread across vessel types, hard fouling was found in nearly every case. Even more alarmingly, it was found that 44 per cent of vessels had more than 10 per cent hard fouling coverage, a level that is deemed unacceptable by industry standards.

Based on this finding, this level of unacceptable fouling is having an alarming effect on the environmental impact of the shipping industry. When calculating the scope of this effect using data from a 2001 study titled Economic impact of biofouling on a naval surface ship by Schultz, with 44 per cent of vessels having at least 10 per cent of hard fouling coverage, a conservative estimate is that an extra 110 million tonnes is being added to shipping’s carbon footprint. Furthermore, we estimate that it is adding at least another $6 billion to the global bunker bill, which again, is a conservative calculation based on today’s relatively low fuel prices.

Financial penalties from biofouling can also accumulate from beyond the fuel tank. An over-reliance on cleaning solutions can be extremely costly, as the abrasive mechanisms used can often damage the antifouling coating on the hull, significantly impacting the antifouling properties of the coatings for its lifetime. This can get owners stuck in a vicious and expensive cycle of fouling accumulation and regular cleaning costs per year. 

Also, when anticipating future legislation around biofouling, it is expected that the regulatory landscape will become stricter. Hull biofouling has been identified by the International Maritime Organization (IMO) as being a vector for the spread of invasive aquatic species between different ecosystems with great risk to local biodiversity. Already, vessels with a heavily fouled hull have been denied entry from ports until the hull is clear of biofouling.

Countries such as New Zealand are already taking a hard-line approach to biofouling condition on underwater hulls. In time, we expect this attitude to spread as a consequence of the establishment of the GloFouling project by the IMO in 2017. Given the current variances and expansion in fouling legislation, owners of all sectors cannot risk being denied port entry based on the condition of their hulls, presenting another commercial risk to vessel created by fouling.

Given the commercial pressure points created by biofouling, owners need to be ensuring it is not eroding profitability, especially in the face of significant market uncertainties and while the cruise and ferry industry continues to feel the effects of the global pandemic. Vessels should be protected against biofouling when in active service and when idle for long periods, particularly against highly impactful barnacle fouling since this is a creature that can only strike when a vessel is sat still in the water for a couple of weeks or more.

Therefore, a large proportion of idle passenger ships throughout 2020 means the level of unacceptable hard fouling coverage has more than likely spiked significantly compared to the data findings in our research conducted with Safinah last year. 

So, what steps can owners and operators take to ensure they are not having their profit margins being invisibly eroded by barnacle fouling during these uncertain times? The first step needs to be a close dialogue between owners, operators, yards and paint manufacturers, along with a more rounded appreciation of the types of technology that can help to prevent fouling accumulation. 

One key area is to examine is the idle period guarantee given for a particular antifouling coating. Given the unexpected idling and lay ups we’ve seen so far this year, in the future owners need to be considering antifouling coating idle guarantees that go beyond the typical 30 days, especially if a vessel will be frequenting biofouling hotspots located in warmer waters. 

Typically, when I-Tech’s barnacle repelling active agent Selektope is included in an antifouling coating it allows paint manufacturers to extend idle period guarantees, since the technology delivers superior hard fouling prevention, acting as an insurance against highly impactful barnacle fouling. 

In a sector that has led the adoption of green technologies for improved vessel efficiency to improve environmental credentials, owners and operators of cruise vessels and ferries should also be very aware of what’s accumulating below the waterline and proactively protect hulls with antifouling coatings that can withstand great biofouling pressures, even when a ship is sat still for long periods. It’s a challenge, but the technology is available. 

Markus Hoffmann is technical director at I-Tech AB

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By Markus Hoffman
09 December 2020

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