John David of the consulting firm Marine Professionals said the introduction of low-sulfur emissions in ever-expanding areas of the world’s oceans, and the move to reduce the level of sulfur in bunker fuels will have the effect of increasing cat fines in the fuel.
“It is a fundamental trade off between the engine and the environment,” he said. “You cannot have low sulfur and low cat fines.”
Claims arising from excessive main engine wear caused by cat fines in fuel oil can exceed $1 million and there is no sign of the problem being remedied at the source, said Paul Hill Braemar, chief surveyor for Western Europe.
Hill explored the discrepancy that exists between ISO standards for cat fine content and the recommended content by engine manufacturers. Explaining this placed the onus on effective filtration, purification and fuel management on board the vessel, he expressed concern that on board purifiers often have insufficient capacity and poor efficiency for the task, and operators do not know in advance the quality of fuel being brought on board.
“The leading main engine makers MAN B&W and Wartsila specify fuel with a maximum of 15 ppm (parts per million) cat fines to be used in their engines, yet the ISO limit remains higher, with refiners reluctant to pass on – or absorb – the additional costs involved in supplying fuel at the recommended level,” he said. ”They take the view that as all ships are built with a fuel treatment system that is capable of removing the cat fines to a level below the 15 ppm stated by engine makers, the onus is on the vessel operator to treat the fuel system.
“Yet ships' engineers are operating with one hand tied behind their back as they often do not know and cannot predict the quality of the bunker fuel being brought on board. In addition the industry has seen a fall-off in good maintenance practices, such as regular cleaning of fuel oil settling and service tanks. There are also industry wide concerns that there is a tendency for shipyards to fit purifiers of the bare minimum capacity in order to save them money but invariably at a detriment to the shipowner,” Hill said.
He recommended that all fuel received on board be treated.
However, he pointed out vessels should be equipped with filter systems which will keep cat fine levels to below 15 ppm which is the recommended level for engine safety.
“Therefore the question has to be asked 'what is the problem?'” he told delegates. “The problem as we all know is with the crew’s competency.”
He warned the inevitable result of the lower emissions target will be a rise in the damage caused by cat fines which can destroy engine cylinders and, in extreme cases, could leave vessels without power and drifting in busy sea lanes.