The crew on board ship # 1 experienced that there was a mismatch between satellite derived positions, i.e. their representation on both ECDIS and paper charts, and the correct spatial position of the ship, which could be verified from terrestrial observation methods. This was the reason for a sound skepticism towards the ECDIS as it was expressed by several crew members (Respondents A, C & D). From the crew members´ point of view, the conditions made it necessary to use terrestrial techniques on many occasions to obtain a trustworthy representation of the ship´s position, and plot this in a traditional sea chart. One account of a near-miss was given by a crew member:
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On approach to port, following a turn, the representation on the ECDIS screen suddenly did not match the visual representation obtained from looking out of the window. An island was on the wrong side of the bow. This was highly confusing. (Respondent D)
The mental model of the situation was instantly shattered and required a rapid reconstruction. This incident was an overarching barrier hindering the ECDIS in becoming a fully integrated, or trusted, element in the bridge´s system of position referencing, therefore it often functioned only as a secondary reference, subordinate to other more basic methods. During critical maneuvering, for example navigation close to shore, the use of ECDIS was directly abandoned.
Although ship #2 was fully ECDIS compliant, additional paper charts were kept, although they were not updated regularly, so they served as an additional, unofficial, reference in case the ship needed to make voyages beyond its regular trading routes. Two elements were emphasized as the reason for this; the first being a matter of trust (the level of trust in the ECDIS was high if the route sailed was well known from previous experience and cross referencing between terrestrial data and ECDIS data, but declined as the waters navigated became less familiar), and the second being that the crew members found it easier to obtain an overview on a traditional paper chart, also during route planning. Furthermore, regular IT issues were experienced (infrequently though). The latter included loss of system sensor input and system freezes. Normally the issues could be resolved by restarting devices, or the system, but until the reboot was completed; “we have practically no navigation aids” as a crew member expressed it (Respondent F).
The perceived benefit however of the bridge systems integration on board ship #2 was that different representations could be cross-referenced instantaneously; “does RADAR and AIS tracks correspond, and land features or navigational marks shown on the ECDIS can match the RADAR echoes?” (Respondent E). Thus, terrestrial and satellite information was used to verify each other at a glance.
On board ship #3, uncertainty about the trustworthiness of the data quality presented by the system was expressed. Sources of uncertainty comprised discrepancies observed from comparison between instruments, at certain instances: During berthing the ship contour did
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not match the berth represented on the chart. Thus, the crew finished the chart design by manually drawing a virtual line that matched the ship´s contour and indicated when the ferry had docked. The ECDIS did not communicate to the crew, it was imprecise in its representations and, thus, it was left to the crew to assess the reliability of the representation provided, by integrating other information, and personal/collective experience. One crew member expressed: “I can only use it for approximation, when I ought to be able to use it for navigation” (Respondent I). Another crew member expressed that the ECDIS was not found to provide the same level of overview as the traditional paper charts offered (Respondent J). 2. Hermeneutic mode of operation – enhance system communication and transparency.
The crewmembers on board ship #1 found the ECDIS very useful (Respondents A,B,C & D), but knowledge gained from experience was necessary, to determine when the data on the screen could be trusted as the system did not communicate to the user when the position representation displayed was unreliable, and thus it was found ignorant of its own incapacity to show true location. The usefulness of the system in terms of real-time position representation and ease of route creation, and deviation from a route, which was often necessary, made the crew pick from among the ECDIS functionalities the ones they found feasible and integrate the perceived benefits with those of other strategies deployed for navigation.
Due to the trade pattern of ship #2, the crew members seldom had the need to plan new routes as these were re-used. Further, an effect of the trade pattern was that the crew members were very familiar with the routes sailed, including any navigational obstructions and dangers, and new crew members were quickly familiarized with the trade. This meant that any perceived shortcomings of the ECDIS were compensated for by integrating the information provided by the system with the individual experience, and the collective knowledge present on the bridge (experience sharing), and thereby the crew members could fill in the blank spots. An example of this was the missing representation of known navigation marks on the ECDIS chart. Unaware of the fact that representations of chart details at different zoom levels was determined by the system itself as a feature in the default setup, the crew members did however have a hard time figuring out why navigation information such as particular navigation marks and depth contours were not represented at certain chart zoom-levels at certain positions (Respondents E & F). Thus, a slight mistrust in the processes behind the electronic chart construction had developed on board.
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3. Automation vs. Operator control – understanding of limitations in various contexts.