Engine stops after bunkering at a public pier
After taking about 400 litres of diesel from a road tanker at a public pier, a 12 m workboat gets underway to carry two technicians to a site about 3 nm away. Ten minutes later the 150 kW engine begins to hunt, loses power and stops. The primary filter bowl contains a milky fluid and dark sediment; the secondary filter was changed the previous week. The vessel is drifting near a busy ferry route with a strong cross-current and no mechanic is available for two hours. The operator has one spare primary filter, a drain can, hand tools and a VHF radio. The tank has no quick-drain fitted and the fuel delivery note shows no sample was taken. The owner wants the technicians delivered on time and suggests repeated restarting.
1. What immediate actions would you take to prevent collision or further damage after the engine stops?
Read the worked answer
Inform the master and treat the vessel as a priority: control the drift, keep clear of the ferry route, and prepare the anchor. Display the correct lights or shapes and make a short VHF call if risk of collision exists. Do not keep cranking the engine; repeated starts can fill the cylinders or damage the starter and will not fix contaminated fuel. Isolate the fuel supply, close the tank valve if appropriate, and secure the engine. Check for leaks and take a fuel sample before any restart. The immediate aim is to keep the vessel safe and create time to diagnose the fuel problem properly.
2. How would you diagnose and deal with the contaminated fuel, and what are the limits of any temporary fix?
Read the worked answer
Draw a sample from the primary filter drain and, if possible, from the tank bottom. Milky fluid indicates water; dark sediment suggests dirt or microbial growth. Drain water from the filter bowl, fit the spare primary filter, prime and bleed the system, then run briefly and watch the bowl. If a separate clean tank is fitted, switch to it and preserve the suspect tank for polishing. A temporary filter change may last only minutes if the tank is badly contaminated, so do not commit to a long passage; arrange a mechanic, fuel polishing or fresh fuel. Keep samples and the delivery note for the supplier claim.
3. What bunkering checks would have prevented this situation?
Read the worked answer
Before bunkering, dip or sound the tank, confirm available capacity, and check the delivery note. Take a continuous sample at the receiving point and a tank sample before and after; use water-finding paste on the tank dip. Confirm the fuel is the correct grade, supervise the transfer, and check filters and water separators afterwards. Record quantities and retain samples. These checks would have shown water or sediment before the engine was committed, and they give evidence if the supplier disputes the quality.