The purpose and scope of this paper is to describe the factors to consider when determining Electronic Chart Display and Information System (ECDIS) limitation, data reliability, alarm management and ship’s safety parameter settings. For the optimum situational awareness, navigators must always recognize the level of display for objects presented when using ECDIS. The values for the safety depth and safety contour must be understood and entered to achieve a sensible and considered meaning and alarm settings. The navigators must remember that the display of underwater obstructions or isolated danger symbols can change according to the settings of this safety contour which also marks the division between navigable (safe) and non-navigable (unsafe) water. Improper management of the system may result in the anti-grounding alarms and other indications failing to activate as required for the safe conduct of the navigation. Consequently, it could give a false impression of safe waters around the vessel where some dangers may not be shown due to the limitations imposed by original chart scale. This paper recognizes the limitations of ECDIS display, the significance of appropriate safety settings as well as the alarm management recommended for passage planning & route monitoring on VLCC tankers.