Ecdis and ENCs improve navigation safety
Publicado por mjsigol
The implementation and use on board of ecdis has reduced navigation risk. Ship groundings and collisions can be avoided if ecdis is used correctly, with all alarms set properly. Safety is also improved if navigators refer regularly to other navigation aids, such as radar, and maintain situational awareness by looking out of the bridge window. Extensive training of bridge teams in the use of ecdis and other systems is also an important element of safe navigation.
The use of ecdis and electronic navigational charts (ENCs) on ships has reduced the number of casualties, said ship insurer UK P&I Club’s loss prevention director Stuart Edmonston. “Ecdis can improve the safety of navigation. For example, it has significantly improved the accuracy and reliability of navigation charts,” he explained. Corrections and updates, such as wreck and cable positions, used to be added manually on paper charts. But with ENCs the corrections are added automatically, by way of a CD or downloaded through the ship’s satellite communications. Overlays are also possible with data from the automatic radar plotting aid (ARPA) and Automatic Identification System (AIS) superimposed over ENCs.
“Another benefit is that officers can set alarms and parameters on screen, which improves awareness of the navigation risks,” Mr Edmonston commented. “The ARPA, AIS and radar can be laid over ENCs, so all the information is on one screen. This means that officers can navigate the vessel using the visuals on the screen.” He emphasised that officers should continue looking out of the bridge window and not rely totally on technology.
Nonetheless, ecdis and ENCs have helped reduce the number of groundings. “The misreading of paper charts has caused groundings in the past,” said Mr Edmonston. “Ships can drift off the course line, and the depth of water changes before someone notices and the ship then grounds. But if ecdis is being used properly these types of groundings will be less likely,” he commented.
Ecdis training, recertification and onboard procedures are also important elements of safe navigation. “It is paramount that owners maintain training of officers on ships,” Mr Edmonston said. “Deck officers currently need to revalidate their certificates every five years, and ecdis should be written in the safety management procedures. If a new type of ecdis console is introduced on board, there would need to be new type-specific training initiated.”
Ecdis recertification and refamiliarisation training should ensure that officers are competent in using the equipment. “Ecdis is good for the industry in reducing the chances of unsafe navigation by rogue seafarers that do not have ecdis training,” he said. “If ecdis is used properly, it will make navigation safer, although no doubt we will still see some ecdis-assisted casualties. But we will see fewer groundings and fewer collisions because of the capability of the system.”
There have already been some ship accidents where misuse of ecdis was a contributing factor. One of the most recent was the grounding of Ayder Tankers’ 6,444gt product tanker Ovit on the Varne Bank in the Dover Strait on 18 September 2013. According to an investigation report by the UK’s Marine Accident Investigation Branch (MAIB) the tanker struck the sandbank while following a route on ecdis that had not been configured properly.
The passage plan was unsafe as it passed directly over the Varne Bank. It had been prepared in ecdis by an inexperienced and unsupervised junior officer and was not checked by the master before departure. The scale of the chart on ecdis was inappropriate for the passage, so safety-critical information was not displayed. The operator-defined settings that were applied to the system were unsuitable, and the audible alarm was not on. This meant there were no alerts when the ship crossed safety depth contours. The MAIB reported that the chief officer’s situational awareness was so poor that it took him 19 minutes to realise Ovit had grounded.
The majority of ship groundings, of which there were 20 in the first two months of this year, are due to machinery issues, such as engine or steering gear failure, but there are still plenty resulting from poor navigation. The cost of a ship loss through unsafe navigation can be in excess of US$1 billion once wreck removal and cargo losses are taken into consideration.
Ship insurer Allianz’s global head of marine risk, Rahul Khanna, has estimated the costs of a 19,000 teu container ship sinking. He said the hull loss would be around US$200 million and the cargo costs – 19,000 containers at US$35,000 each – would be US$665 million. On top of this are the removal costs, which could be between US$190 million and US$400 million. “So losses could be in excess of US$1 billion,” he said. These cost estimates were based on the grounding and recovery of Costamare’s container ship Rena, which grounded on the Astrolabe Reef in New Zealand in 2011.
One of the issues with using ecdis for navigation is officers relying too much on these systems. “There have been losses because of the over-reliance on ecdis,” Captain Khanna commented. “Officers relying on ecdis can be overloaded with information,” He said the design and layout of the human-machine interface is important in reducing information overload.
Captain Khanna also highlighted the need to provide more support from shore for deck officers. “We need to ensure the navigator knows how to use the machine for safe navigation. Things change rapidly and there is less chance of the navigator knowing about changes from experience, which is why shore support is important.” Other issues that need to be addressed are the lack of standardisation between ecdis models and the constant addition of new systems with advanced functions. “There can be new models coming in all the time and this is a problem for navigators who are not familiar with them. There are also issues to do with system reliability,” he added.
Issues with ecdis technology were discussed at Riviera Maritime Media’s Tanker Shipping & Trade conference in London in November 2015. During a panel discussion, International Registries chief operating officer John Ramage said seafarers rely too heavily on the equipment, and do not have enough experience. “Now seafarers see what is on ecdis as the gospel truth, and never question this. They are too reliant on the technology,” he said. He also said that the misuse of AIS equipment has been a contributing factor in ship collisions.
From the audience, Anglo-Eastern Univan Group marine director Peter Helm commented on the issues with ecdis implementation and the risk of ecdis-assisted groundings. “When ecdis was designed, seafarers were ignored,” he commented. “If seafarers had been consulted, we would not need type-specific training.”
The head of the Danish Maritime Accident Investigation Board, Oessur Hilduberg, agreed that ecdis, radar and AIS equipment should be considered aids to navigation and not totally relied on. These systems should provide navigators with data and information about what is happening in waters around the ship. “It is seafarers who have to make decisions based on this information,” he said. If they are fed incorrect data or systems are not operated correctly, then there is a greater risk of error.