A crucial choice

Marshall: Marshall: "How many fines, lost contracts and days off charter does it take until that saving [on a cheaper BWMS] is gone?"

Care when selecting ballast water management systems would make life easier for owners, Andrew Marshall of Coldharbour Marine tells Gavin Lipsith.

“A ballast water management system has the potential to fundamentally ruin your day,” says Andrew Marshall, CEO of inert gas generator and ballast water management supplier Coldharbour Marine. It may be one of the more perverse sales pitches this reporter has heard.

Given the myriad pitfalls confronting the owner of a faulty system, he may have a point. Those woes include disrupted loading (if you have to take on and discharge ballast to handle cargo), failed Port State Control (PSC) inspections and, potentially, reputational damage amongst charterers. But ship operators could avoid these issues simply by choosing their treatment with care, says Marshall.

“You can find a ballast water management system for a very large crude carrier at less than a million dollars,” he says. “Ours is listed at US$1.4 million. But how many fines, lost contracts and days off charter – don’t forget that PSC has the power to send you back to international waters to discharge and re-ballast - does it take until that saving is gone?”

Marshall is outspoken about the IMO type approval process, suppliers abusing it and the US Coast Guard stance on UV systems.

“I think the approach by some ship owners and flag states to delay the BWM convention process so long has eroded any leeway they can expect from the international community on other issues, for example the sulphur and greenhouse gas challenges,” he says.

He argues that the approach of some owners, who opt to hide behind type approvals without looking further into whether a system meets their operational needs, will not help them when it comes to enforcement. He cites a presentation from American P&I’s William Moore in late 2016, when Moore told owners (to paraphrase) not to come running to the club if they have a problem after choosing a system that is not fit for purpose.


A type approval certificate does not guarantee that a system is fit for all types of vessel and under all operating conditions, Marshall explains.  It’s up to the owner to ensure that the technology purchased will do the job under all the operating conditions and requirements for the vessel.  Each of the treatment methods has its own limitations. Coldharbour’s own system, for example - which uses inert gas and a brace of auxiliary ‘kill’ mechanisms to treat water – would be inappropriate for any vessel with less than five days’ sailing between ports.

The system was designed with a very specific class of vessels in mind: big tankers, bulkers and gas carriers. Such ships have a unique set of factors that require special consideration when treating ballast water, says Marshall.

“We wanted to tackle three issues. First, how to treat ballast water on vessels with a high pumping rate that is crucial to loading operations. Second, how to treat serious volumes of water – up to 100,000m3 for VLCCs and up to 250,000m3 for VLOCs. Finally, how to confront the issue of regrowth for ships on long trades.”

Regrowth is key. The IMO and USCG type approval testing regimes demand that samples be taken five days and a single day respectively after treatment. The aim is to show that regrowth has been prevented. But, evidenced by a plethora of biological studies, Marshall argues that these ‘holding periods’ are far too short to allow regrowth to begin in the first place. Any significant gap between treatment and discharge will lead to regrowth, and could result in ship owners breaching discharge standards even if they use type approved systems.

The Coldharbour solution tackles regrowth by making the water in ballast water tanks uninhabitable until it is discharged. ‘Gas lift diffusers’ (GLD) in the ballast tanks infuse the water with inert gas, stripping it of oxygen. The diffusion also increases carbon dioxide levels, leading more organisms to die of hypercapnia. The gas is diffused through USD units - a specially shaped component tuned to the ‘destruction frequency’ of bacteria, ensuring more organisms perish in an ultrasonic shockwave. And a stream of microbubbles, forced through the shockwave, creates a cavitation effect that causes yet more damage to the unfortunate organisms.


The tanks are kept in a de-oxygenated state for at least 60 hours. Around 18 hours out of port, the water is re-oxygenated in preparation for discharge. The problem of regrowth is solved, while the in-tank solution neatly sidesteps issues related to flow rates, water volumes and cargo operations.

Marshall is happy with Coldharbour’s order book, noting that the company’s plan anticipates a sales ramp up over the next 2-3 years. Coldharbour is currently working through three multi-ship orders, one with TMS Tankers and two others that will be made public next year. “Both have been through the pain of working with inappropriate systems,” Marshall reveals.

That is the crux of the company’s message to ship owners: System selection must be appropriate. It is a message that cuts both ways, and Marshall claims Coldharbour has both lost and turned down orders as a consequence. But if the result is that fewer owners have fewer problems with their ballast water systems, that will ultimately benefit owners, suppliers and the industry as whole.


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