Fuel Contamination Causing Power Loss Prompts Coast Guard Warning

A towing vessel’s fuel supply was so contaminated with water that it lost power recently, prompting the United States Coast Guard’s Office of Investigations and Analysis to issue a Marine Safety Alert May 19 warning towing vessel operators to be aware of fuel contamination. 

According to Safety Alert 06-22, a towing vessel operating in a pushing-ahead configuration experienced a loss of all propulsion while operating on the Mississippi River. The loss of propulsion occurred approximately three hours after getting underway and about 3.5 hours after receiving fuel from a shoreside facility.

Fortunately, the Coast Guard said, there was no significant damage to the vessel, nor injuries to crewmembers. An investigation into causal factors revealed that the vessel’s fuel tanks and fuel service system to the engine were heavily contaminated by water. The amount of water contamination was so significant that the vessel’s engines initially suffered a reduction in power and eventually shut down completely, resulting in a total loss of propulsion. 

Smaller inland vessels often don’t have the centrifugal purifiers that ocean-going ships use to ensure that fuel reaching engines is free of all contaminants, including water. They may have only one or two filters installed directly in the fuel supply line, and those types of filters are not as efficient in removing contaminants. 

The Coast Guard strongly recommended that vessel owners and operators: 

• Ensure that fuel supplies (bunkers) meet the engine manufacturer’s specifications for important parameters such as viscosity and cetane number, as well as any regulatory requirements such as flash point and sulfur content. 

• Include regular fuel oil sampling and testing from service tanks as part of a periodic maintenance system. 

• Ensure that fuel filters are of the correct flow rate and filtration (micron) rating, and that an adequate supply of spare filters is kept onboard. 

• Consider the use of duplex filter systems to enable switching from clogged to clean filters, as well as the use of filter differential pressure gauges to monitor the condition and cleanliness of the filter element. 

• Consider the use of a water sensor in diesel tank or filter system to monitor water content in fuels. These sensors may be combined with displays and alarms to indicate excessive water and are generally more effective at detecting rising water content than periodic manual sampling. 

• Ensure that a means is provided, usually by a valve and piping arrangement, to periodically sample the fuel being received during bunkering. 

• Have a plan in place to recover from any engine shutdown that occurs because of water contamination in fuel. Fuel severely contaminated by water or other impurities has the potential to cause damage to the engine in a number of ways, including subsequent contamination of the lubricating oil system.

The Coast Guard urged casualty investigators, marine surveyors and inspection personnel to “maintain an acute awareness [of] these issues and initiate corrective actions as needed.”