ECDIS stand electronic chart display and information system. It is updated with the help of a CD.
An ECDIS is a unified navigational information display which presents on an updated chart background,updated route,present position and fast track, combining these as approprite with radar,ARPA and other navigational sensors in order to improve safe navigational through the clear display of the situation in the vicinity of the ship.
chart can be corrected through a floppy disc,compact disc, even directly through the satellite systems. The latest system of updating charts is that the manufacturer transmit the chart updated as broadcast in coded format. Dedicated software is fitted in the ECDIS which will receive these updates,decode them and correct the charts.
intact stability of any ship is the minimum stability requirement to be considered safe for sea going,you can read the full intact stability criteria for all vessel here