## 2 Background and Previous Research  
The SOLAS Convention requires installation of one ECDIS system on board vessels engaged in international voyages, other than non-tanker cargo ships with a gross tonnage of less than 10,000 built before 1 st of July 2013. [1]. As a back-up arrangement imposed by carriage requirements, the following means have been recognized: (i) an Appropriate folio of PNCs (APC); (ii) autonomous system equipped with an independent emergency power supply; and _iii)_ chart Radar [2; 3; 4]. The advantages of ECDIS navigation over traditional means can be summarized as workload reduction; task automation; and, as stated by the International Maritime Organization [5], the system usage contributing to the safety of navigation, particularly referring to predefinition and settings of safety parameters. Contrary to benefits, the system has been considered as a nonautonomous, still dependent on external factors such as sensors and hydrographic data, and prone to failures, malfunctions, and inability of proper performance nevertheless the root cause. The proper education and the lack of knowledge have been further recognised as drawbacks. This current-state pros and cons outcome, together with the desired path towards navigational safety have been the motivation for the research and for the results obtained and presented in continuation. For ECDIS to be accepted as a system which meets charts carriage requirements, the following conditions have to be met: (i) the system has to be type-approved. (ii) it is necessary to employ up-to-date ENCs; (iii) the system software has to be maintained and compatible with the latest IHO standards; and, (iv) the system needs to have adequate and independent back-up arrangements [3; 5; 6; 7; 8; 9]. During the ECDIS transitional period, several issues regarding the system have been recognized [10], although the current scientific collection of findings has been relatively scarce. The analyses of ECDIS-related accidents have emphasized the need for a more efficient system operation [11; 12]. The previously conducted surveys and research results on justification of the system have indicated potential problems on different levels, generally related to the system, installation, maintenance,positioning, handling, navigation, insufficient operator's knowledge, ENCs production, displayed chart symbols without their features, etc. [10; 13; 14; 15]. The summarized problems and difficulties (Figure 1) [13] have served as a further step towards the research. An overview of the existing ECDIS-related training has suggested some potential improvements in the training for deck officers, as well as in the increase of operational awareness [16; 17; 18]. There is no evidence that the system will be better accepted if system operators are more experienced seafarers [19]. Considering the particular navigational rank engagement and interaction with the system, a continuous need to adopt ECDIS Education and Training (EET) for an individual rank has appeared. The risks of overreliance, lack of situational awareness, and other subtle problems should not be disregarded [13; 15; 20]. The navigator has to be aware of the system limitations and should always cross-check displayed information on the ECDIS with available and suitable sources [21] due to the risk that the safety of navigation is compromised by infrequently utilizing basic safety settings [22; 23]. Furthermore, lack of standardization of the system settings, display, functions, and terminology among system manufacturers has showed a negative impact on the safety of navigation [24]. In Figure 2, a share of answers [20] referring to opinions on advantages of both navigational means has been presented, with the justification of opinions related to the main features. To prepare for the future of PNCs, some critical issues on the subject have been introduced to the IHO and hydrographic offices [25].