Low sulphur fuel behind increase in propulsion loss incidents
Low sulphur marine gasoline oil costs around double the price of high sulphur residual fuel oil. Credit: HG Machinery
The low-sulphur fuel switch is behind a rise in propulsion loss incidents, according to Gary Rawlings, marine engineer consultant at TMC Marine.
Rawlings told SAS that California ports noticed a marked increase in vessels suffering from propulsion loss following the introduction of more stringent emission control areas (ECA) in 2015, and it continues to be a problem. “A lot of cases of propulsion loss are due to fuel failure,” Rawlings said during a talk at London International Shipping Week (LISW). “I attended a vessel that changed [to low-sulphur] fuel in the English Channel and the procedure was not done properly. The fuel pump plunger seized and damaged the cam, which broke the cam follower. The vessel had to stop in the Channel, disable the unit and limp to port.”
The current global limit for sulphur content of ships’ fuel oil is 3.50% m/m (mass by mass) as part of the revised MARPOL Annex VI, which significantly strengthened requirements and entered into force on 1 July 2010. However, ships face tighter restrictions in designated ECA: for example, on January 1, 2015, the new fuel oil sulphur limit authorised by MARPOL Annex VI, Regulation 14.3.4 came into effect, lowering fuel sulphur content from 1.0% to 0.10% for vessels operating in the North American and U.S Caribbean ECA. As a result, vessels using higher sulphur content fuels must change to ultra-low sulphur (ULS) fuel oil to comply.
And starting in January 2020, the global sulphur limit will drop to 0.50%, except when traveling in designated ECA with 0.10% limits.
The P&I club Gard has previously warned its members that changing to low viscosity low-sulphur fuel can cause
several engine problems, including “thermal shock in the fuel system due to the rapid change in temperature and poorer lubrication qualities of low sulphur fuel”. This can results in “sticking/scuffing of the fuel valves, fuel suction valves and fuel pump plungers, which can lead to shut down of the main engine followed by manoeuvring problems”. However, Rawlings said that all too often crews do not follow correct procedures during the fuel changeover process and proper monitoring and maintenance is not followed, leading to engine failure and loss of propulsion. Research by the London P&I club carried out into the causes of propulsion loss over the last five found that 29% is down to insufficient or ineffective maintenance, closely followed by human error (24%) and equipment failure (24%).
In order to reduce such incidents, TMC Marine has launched a booklet on how to prevent marine engineering issues and procedures that cause loss of propulsion incidents and blackouts. Developed in collaboration with Bureau Veritas and the London P&I Club, the booklet provides general guidance and practical advice to marine engineers and ship owners on the causes of blackout and main engine failures, the risks associated with propulsion loss and the precautions that can be taken to prevent these risks. TMC Marine stressed it does not intend to replace IMO regulations and guidance notes or documentation forming part of a vessel’s safety management system but is “a practical tool for all involved in shipping”.
"All propulsion loss incidents should be treated as a major incident and investigated with root cause analysis carried out by trained personnel and preventative and corrective actions developed. The consequences of just one loss propulsion event in a busy shipping route can cost tens of millions” said Rawlings.
This is the second booklet in a series on loss prevention issues by TMC Marine, the first ‘Reducing the Risk of Liquefaction” was published in March 2017. Download Reducing the risk of propulsion loss here.