North P&I Club is advising its members to be aware of the potentially severe consequences of poorly maintained or overloaded on-board generators being unable to meet the electrical demands of ships at sea. The warning about reduced generator capacity comes in the latest issue of the club’s loss prevention newsletter Signals.
According to deputy loss prevention director Colin Gillespie, ‘Generators have a critical function to play on all ships. They provide electrical power for ever-more complex navigation, communication and safety systems as well as essential on-board services and vital equipment such as cranes, winches and bow thrusters. If the generators cannot cope due to poor condition or excess demand, it can lead to total loss of electrical power and put the safety of the ship, crew and cargo at risk.’
North says insufficient generator maintenance is a common industry failing. ‘People tend to think of generators in terms of their alternators, which have few moving parts and are quite robust,’ says Gillespie. ‘But the diesel engines that drive them need the same level of care as a ship’s main propulsion engines. Components wear, turbochargers get dirty, compression drops and combustion deteriorates. A good monitoring and maintenance regime, including sufficient spare parts, is essential.’
He says the issue can be particularly acute on container ships where owners have increased the number of refrigerated containers carried without properly considering generator capacity. ‘In such cases the generators, if not perfectly maintained, may be unable to meet the combined power demand from the reefer containers when both the bow thrusters and mooring winches are being used. This has resulted in generators becoming overloaded and tripping out, leading to potentially dangerous blackout situations.’
North says crews often attempt to pre-empt such blackouts by switching off one electrical system so another can be used. ‘We have seen a number of incidents recently in which reefer boxes have been unplugged to allow sufficient electrical capacity for berthing operations. The containers typically remained off-power until the vessels were secured alongside or they were discharged ashore, often for several hours,’ says Gillespie.
‘High-value cargoes such as medical and pharmaceutical products can be very temperature-sensitive, and this practice can result in large claims against shipowners if containers are not kept at the correct temperature.’
