Insights · Navigation · ECDIS
For centuries a ship's position was a pencil mark on a paper chart. On most merchant ships today it is a glowing dot moving across a screen, drawn from satellites, radar and an official electronic chart. That system is ECDIS — and since 2018 it has been the fleet's primary way of finding its way.
Navigation used to be a craft of paper, pencil and parallel rules: a position fixed by hand and plotted on a chart that had to be corrected by weekly Notices to Mariners. ECDIS — the Electronic Chart Display and Information System — folds all of that into a single computer on the bridge. It draws an official electronic chart, overlays the ship's live position from GNSS and AIS and radar, and continuously checks the planned route against the dangers around it.
The crucial point is legal as much as technical: a type-approved ECDIS, fed with up-to-date official charts, may serve as a ship's primary means of navigation — the paper chart is no longer required. That single permission is what turned ECDIS from a useful aid into mandatory equipment.
Two acronyms get confused. ECDIS is the system — the screen, the processor, the software on the bridge. ENC — Electronic Navigational Chart — is the data: the official vector chart issued by a national hydrographic office, built to a common international standard so that any compliant ECDIS can read it. An ECDIS only satisfies the law when it is loaded with current, officially issued ENCs; running on unofficial or out-of-date data does not count.
Beyond drawing a chart, an ECDIS is an active safety tool. It can:
ECDIS is mandatory under SOLAS Chapter V, Regulation 19, on safety of navigation. Rather than switching the whole fleet over at once, the IMO set a phased timetable running from 2012 to 2018 — newest and highest-risk ships first, older and smaller ships last.
| Ship category | Brought into ECDIS carriage |
|---|---|
| New passenger ships ≥500 GT & tankers ≥3,000 GT | from 1 Jul 2012 |
| New cargo ships (non-tanker) ≥10,000 GT | from 1 Jul 2013 |
| New cargo ships (non-tanker) 3,000–10,000 GT | from 1 Jul 2014 |
| Existing passenger ships & tankers | at first survey, 2014–2017 |
| Existing larger cargo ships | by first survey to 2018 |
Existing ships were brought in at their first survey after a set date for each category, so the last of the larger cargo ships were equipped by 2018. By the end of that schedule, ECDIS was effectively standard across the international trading fleet.
ECDIS did not just digitise the chart. It moved the watchkeeper from plotting a position after the fact to watching a danger develop in real time. On SOLAS Chapter V and electronic navigation
ECDIS is also where navigation meets tracking. The same satellite positioning that feeds an ECDIS bridge feeds the AIS broadcasts that put a ship on a public map — and when a vessel deliberately switches off its transponder, the contrast with its known navigational capability is one of the markers of dark activity. A ship's type, size and build year tell you which ECDIS rules applied to it. On Marifest you can search any of 97,000+ vessels in the registry, read those specs, follow the vessel on the live map where positions are available, and check its compliance standing. The terms used here are defined in the maritime glossary.
How Marifest uses it
ECDIS and AIS draw on the same satellite fix. Marifest takes that position and turns it into a public track — and notices when it disappears.
Where AIS is available, the live map shows a vessel's position drawn from the same GNSS fix its bridge navigates on.
Type, size and build year decide which ECDIS carriage rule applied to a ship — all on the file.
A capable ship that goes dark stands out. Position gaps are part of the dark-activity picture Marifest surfaces.
Specs, position, flag and sanctions standing sit together, so navigation never reads in isolation.