ELECTRONIC CHART DISPLAY AND INFORMATION SYSTEM (ECDIS): SOME LESSONS LEARNED
Published: April 1, 2016
SOLAS Chapter V Regulation 19 makes the carriage and use of ECDIS mandatory on certain classes of ships and by July 2018 it will be mandatory for all existing tonnage over 10,000 gt. There have been several recent incidents which have highlighted difficulties in implementing the use of ECDIS and in this article we will set out the regulatory requirements and point out some of the lessons that can be learned from the recent incidents.
SOLAS Chapter V Regulation 18 states the ECDIS must be type approved by the flag state and tested by a recognised ‘notified body’ and requires a certificate which states the performance standard against which the ECDIS is approved. The IMO also requires generic ECDIS training.
The flag state may have their own requirements for the installation, with particular requirements for back up systems that can take over in the event of a system failure. This is normally another independent ECDIS or an up to date paper chart system.
The ISM Code infers that the deck officers on board should be completely familiar with the ECDIS model on board. Thus, type specific training may be required by flag state although there is currently no internationally agreed requirements for this type of training.
The ECDIS must be maintained to the latest IHO standards. (IHOS-52 Specifications for Chart Content and Display Aspects). The presentation requirements library of this module has just been revised with an upgrade covering:
- Mariners choice to select alarms above a basic navigational minimum
- Configuration of alarms when fitted
- Light/ beacon/ buoy/ landmark extra information
- A magenta ‘d’ for seasonal marks
- Standardisation of symbology for indication highlights and automatic updates
This will take the form of a software upgrade to current ECDIS equipment. However, we understand some ECDIS units may not be compatible with the new presentation library. This update is mandatory for ships using ECDIS and must be in place by 1 August 2016 or the first survey after that date. The ECDIS will be tested against test data contained in S-64.
ISSUES FOUND DURING LOSS PREVENTION INVESTIGATIONS
ECDIS used for ‘training purposes’
Where a ship is reported to be carrying ECDIS for ‘training purposes’ this can be cause for concern. When ECDIS is fitted on board, and not all deck officers have the requisite certification, the system cannot be used as a primary means of navigation. Therefore paper charts must be used for all passage plans. If ECDIS is being used on board for training purposes then there must be a sufficient number of fully qualified navigators to supervise the training and ECDIS can never be used for the primary navigation. The SMS should cover all these aspects whenever ECDIS is fitted on board for training purposes only.
Port state control (PSC) issues
PSC may inspect type-specific certificates against the actual ECDIS as installed. They may also inspect the certification of officers on board and check that all officers on board have had the required training. PSC may also review previous passage plans in order to ascertain whether ECDIS or paper charts are being used. Ships have been detained where the primary source of navigation should be paper charts but investigation by PSC has found that ECDIS has, in fact, been used as the primary source of navigation. PSC may also check that the ECDIS is listed in the ship’s record of equipment; it is considered a critical system in the ISM Code and therefore must be fully adopted in the ship’s safety management system (SMS) which will include details of planned maintenance and the importance of carrying critical spares.
GROUNDINGS: HOW ECDIS HAS CONTRIBUTED
One of the recurring aspects of reported groundings involving ECDIS is the use of audible alarms. There are often too many audible alarms, from ECDIS and from other equipment on the bridge, and this is a concern that has been raised by various marine investigators. This has been addressed, at least in part, in the revised presentation library where it states that navigational alarms should be set to a minimum by the navigator, using his discretion or in accordance with company policy. This however does not impact on the number of system alarms, which still have potential to cause confusion and distraction.
In one example, there were frequent requests from the ship’s command to the managing company to disable the alarms. The company therefore sanctioned the disabling of alarms without informing class which had the effect of making the system non-compliant with IMO performance standards.
In another reported case, the visual navigation alarm indicated the ship was running into shallow water but it was not noticed by the navigator due to the fact that he was concentrating only on collision avoidance. The audible alarm was not connected and as such was not compliant with IMO performance standards. Crucially, despite the lack of audible alarm the navigator appeared compliant, apparently still relying on the ECDIS to somehow alert him despite the lack of audible alarm.
Too many alarms have been shown to cause alarm fatigue and to be a major distraction to competent watch keeping. However, disabling all ECDIS alarms prevents the system from functioning properly. This problem presents some challenges for the future development of performance standards for ECDIS, but for the time being the audible alarms must be connected and operable. Good installation enabling all inputs to be fully integrated can go a long way to reduce the number of alarms.
Correct use of ECDIS safety settings
In most cases reviewed by the Club’s loss prevention department, one or more of the safety settings was incorrect. Depending on the type of ECDIS, the equipment will have a safety depth feature and some may also have a contour setting. In either case, ECDIS has a safety guard zone. This is an area set by the navigator ahead and to angle on either bow for a safety depth in which an audible alarm should sound if a danger is identified within this guard zone. The safety depth should be used while planning the passage and a safety guard zone used for monitoring the passage.
Contour setting: A safety contour is intended to show the navigator a distinction between safe and unsafe water. Most ECDIS systems are designed for the safety contour to default to 30 metres. At this setting many dangers will be obscured in the unsafe area. For example, on a ship with a draught of 8 metres negotiating the Dover Strait with a default setting of 30 metres, the ECDIS would show much of the Straits as unsafe water. Many shallow patches that the ship would go aground on would not be highlighted. Thus a safety contour should be selected in the same manner as the safety depth described below.
Safety depth: This setting, if set correctly with the alarms functioning, will give an audible and visual warning if there is an obstruction less then the safety depth set. For this to work properly, an accurate chart must be used. Electronic navigations charts (ENC) are based on same the same information as paper charts with the same accuracy. However in ENC this information is referred to as CATZOC (Zone of Confidence Category). For example, Category B has an accuracy of horizontal distance of +/- 20 metres and depth error of +/- 1.2 metres. It is extremely important that this is considered carefully when calculating the safety depth. In most cases reviewed, the safety depth was either not set or set incorrectly.
The safety depth should be calculated as follows:
Safety depth = draught +minimum under keel clearance + allowance for squat + CATZOC depth correction + allowance for swell (if applicable) – height of tide. In some parts of the world the swell should be considered particularly when crossing a shoal or bar in an exposed location.
Cross track distances: This is the distance that the ship can deviate from the planned route before the alarm is activated. This should be set to give a safety margin between the maximum off track distance and the point at which the vessel would cross an obstruction. In one case the company had approved a series of routes without using cross track distance settings. These settings are key to keeping the ship in safe water, particularly in coastal waters.
In all the grounding cases reviewed the ECDIS was not set up correctly for the prevailing circumstances which was compounded in most cases by the audible alarms being deactivated. The navigators were heavily relying on ECDIS despite the reduced alarm capability imposed. The navigators were working in a misguided reliance on the ECDIS being a robust safety asset despite the reduced alarm capability they had imposed. It is extremely important that all who use the ECDIS are fully conversant with the safety features, that they know what they are and how to correctly calculate and set them in the system. There is a need to understand how the structure of overlays work to create the picture on the screen and what features are removed/added with what particular setting.
It is also vital to be on the most appropriate chart scale. Most ECDIS have an automatic optimum scale setting. This should be used and where necessary this can be zoomed in or out but always returning to the optimum setting. This is no different from using paper charts as the same logic applies.
Chart corrections and warnings
A major advantage of ECDIS is that electronic chart corrections can be updated by data input into the ECDIS. However, temporary and preliminary notices have to be added manually. A review of recent cases has shown that, in many cases, those updating the charts have presumed that these notices are included in the weekly chart corrections as an automatic upload which is not always the case. Some chart providers do offer a service to cover this, however it is for the ship operator to ensure that these corrections are updated on the system by whatever means.
In the cases reviewed there appears to be a general conception that ECDIS can be completely relied upon. However, like any other navigation aid, it is only as good as the user. If the information is properly inputted and the safety parameters are correctly calculated then ECDIS is an excellent aid to navigation. Many previous developments such as ARPA were improvements on existing navigational aids such as RADAR. However, ECDIS is not just an improvement on paper charts but rather it requires a conceptual change to the way a bridge team operates because ECDIS consolidates all navigation information and allows for a many different ways to present and utilise that information. Basic ECDIS requirements are set by the IMO, but because there are many manufacturers producing ECDIS models, which operate quite differently and require type-specific training, navigators must make sure that they identify and work with the specific limitations of each ECDIS they rely upon.
In all the cases reviewed, the deck officers were fully trained to IMO and class requirements were met, yet the navigators were often not fully familiar with the functions and settings of the equipment they were using. For ECDIS to reach its full potential it is vital for masters, owners and managers to ensure that good working procedures are fully incorporated into the company safety management procedures for the ship.
ECDIS will invariably have a direct GPS, gyro and log speed feed but visual fixes should be entered to increase situational awareness and avoid total reliance on the GPS positioning.
ECDIS was devised in order to give the navigator more time to keep a navigational watch. What is seen on ECDIS should be used to relate to what is observed outside of the bridge windows. The use of ECDIS does not remove the need for the use of parallel indexing which still has its place. Navigators should not complacently follow the ECDIS, it should be fully understood and carefully monitored like any other system.
Our last observation: ECDIS will make a good navigator better and a poor navigator worse.