Monday, October 8, 2018

Ship Owners Organisation to Help Set Standard For Hull Cleaning and Defeat Biofouling Menace

Container Ships and Bulk Carriers Alike Pay the Price for Dirty Bottoms
Shipping News Feature
WORLDWIDE – When the hull of a vessel becomes covered with a variety of flora and fauna such as the oft seen barnacles, the effect on a modern container or bulk vessel in terms of fuel efficiency can be remarkable when a hull is heavily fouled, a problem recognised over 150 years ago when William Froude, of the Institution of Naval Architects first investigated the effect with his experiments in 1872 and reported to the Admiralty some two years later.

Subsequent investigations have continued ever since and in 2010 a report by J Andrewartha and colleagues recorded increases in drag coefficients up to 99% in test conditions whilst in 2016 light calcareous tubeworm fouling of a VLCC hull was predicted by Monty and his team to produce an increase in total resistance of 34%.

The major problem now facing many ship owners is that today underwater cleaning is only allowed in a few locations around the world, and there is a trend for coastal and port states to tighten their rules for underwater cleaning, as well as an increase in ports prohibiting it all together. This of course may increase emissions from shipping as fouling increases the fuel consumption or in worst case force the ship to change its route.

One of the biggest drawbacks of underwater cleaning is the amount of pesticides released when the hull antifouling coating is scrubbed off to simply pass into the marine environment together with the removed biofouling. It has been estimated that up to 5 tonnes of such coating can be removed from the largest of hulls. These coatings often contain copper and zinc in combination with herbicides such as Diuron and Irgarol.

Now, in response to growing concerns over the impact of hull biofouling on the marine environment, BIMCO, whose members represent around 65% of the world’s maritime tonnage, and a group of industry partners have set out to create an internationally recognised standard. The group consists of eight different organisations, including paint manufacturers, ship owners and cleaning companies, with the aim to take a holistic approach to establishing an international standard that will work in practice. The standard is expected to be finalised in the autumn of 2019.

The standard is intended to ensure that the result of the cleaning is in accordance with a set of specifications, that the environmental impact of the process and coating damage is controlled and that the cleaning process is planned, safe and effective. Part of the standard will therefore relate to how to ensure that the paint is not damaged during cleaning, and that debris and wash-water is collected in a practicable and sustainable manner.

The standard will also cover how ship owners can use it in their ongoing maintenance plans and, most importantly, will establish an approval system for underwater cleaning companies, a currently unregulated and fragmented market. The standard is to undergo thorough practical trials prior to launch, with the aim to send it to appropriate international organisations for endorsement. Aron Frank Sørensen who heads the working group and heads BIMCO’s Marine Technology and Regulation, explained:

“Creating an international standard is important. We need more places available around the world for underwater cleaning. We believe that a standard that is safe, efficient and environmentally sustainable, will encourage States to make more places for underwater hull cleaning available. What is needed today is a standard that ensures that companies providing underwater cleaning services operate to a high standard that can apply wherever in the world they operate.

“Everyone will benefit from it. The cleaning companies will benefit because they will have certain standards to live up to, the ports because they can rest assured that the environment is not polluted by cleaning residues, the paint manufacturers because reporting will be standardized, improving the quality of execution, and the ship owners because they will have more places available for underwater cleaning, once the entire process is regulated and safe.”

Photo: Grinding the biofouling from the hull releases clouds of detritus containing poisonous hull coatings.