Channel Navigation Information Service

The Channel Navigation Information Service (CNIS) provides a radio safety service by scheduled broadcasts or, on request, to individual vessels on passage through the Dover Strait. The area covered by the service extends from the Greenwich Light-float to the latitude of Noord Hinder Light-buoy (52°00'N, 2°51'E) and vessels within the area should listen to the appropriate VHF broadcasts. Radar surveillance is provided by stations at Saint Mergaret's Bay (51'09'N, 1'24'E) and Cap Gris-Nez (50'52'N, 1'35'E) and covers some 110 miles of the Dover Strait, with Cap Gris- Nez a few miles NE of the centre point of the area. The limits of the area surveyed by radar are shown on the chart.

Broadcasts are made by Dover Strait Coastguard and Cap Gris-Nez (CROSSMA) and comprise navigational and traffic information of immediate interest together with the movements of vessels which appear to be acting in contravention of the rules governing the scheme. The latter may be identified by aircraft, helicopters or surface vessels and subsequently reported to Flag States.

Dover Coastguard also provide assistance to establish the position of vessels through a combination of radar, DF and VHF, but caution must be exercised due to the inherent uncertainty in establishing the identity of any particular radar echo.