Issues with thrusters, propulsion or computers were the most common causes of dynamic positioning (DP) events reported in the maritime industry over the past year
Delegates at Riviera Maritime Media’s European Dynamic Positioning Conference were told there were 66 undesired events, 42 DP incidents and 16 observations reported to the International Marine Contractors Association (IMCA).
Of these 124, 45 were down to thruster and propulsion issues and 29 to computer errors. The main cause of 21 was issues with reference systems and 19 from power failures.
IMCA technical adviser for marine Richard Purser said incidents are when a vessel has lost positioning and undesired events are where a vessel “is one failure away from loss of position”.
The largest causes are the effect on thrusters and propulsion (36%), followed by computer (23%), power grid (15%) and references (17%).
“These have the potential to cause the vessel to lose position,” said Mr Purser.
He was particularly worried about the number of vessels that have little redundancy in reference devices for DP and the lack of alternatives to differential global navigation satellite system (DGNSS) devices.
“Although not always the root cause, it is disturbing to see there is a very high percentage of vessels on auto DP with less than three reference, or multiple position reference systems being only DGNSS or the same principle,” said Mr Purser.
Of all the vessels reporting DP issues, 41% of the vessels were not set up as recommended by IMO 1580 M 252 guidance.
The human element is listed in IMCA’s figures as the highest secondary cause of DP issues on vessels as operators react to failures, errors and incidents on vessel systems.
Of the 124 issues reported, 37 were where human element was identified as the secondary cause, 24 were electrical and 22 were computers.
“Humans do not set out to do a bad job or a malicious act,” said Mr Purser, “it is our job to help them make the right decisions through guidance and decision support tools.
Of the 30% attributed to the human element, the main contributing factor was down to sensory issues, errors caused by difficulty distinguishing functions, controls, colours and labelling.
Or memory, where errors were caused by forgetting to make a selection or setting. There were also errors in decisions and actions, where a function or control was selected incorrectly.
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