Survey operations are in progress in the eastern South Atlantic by the vessel Ramform Atlas towing twelve 8000-meter cables; an eight-mile berth is requested.

Reading this warning

DNC (Digital Nautical Chart)

A reference to one of the regions of NGA's Digital Nautical Chart, used to tell the reader which charts a warning affects.

Survey operations

A research or survey vessel is mapping the seabed or water column, often while towing equipment.

Until further notice

The operation or danger has no scheduled end; the warning stays in force until a later message cancels it.

Towed array / streamer

Equipment towed a long way behind a vessel — sonar, a hydrophone cable, a sampling sled — invisible at the surface.

Tow / towing

A vessel towing another vessel, a barge or a structure — slow, hard to manoeuvre, and with a long line between.

Area bound by

Introduces a list of positions that are the corners of an area — the polygon the warning applies to.

Position (degrees and minutes)

How warnings write positions: degrees, a hyphen, then minutes, with N/S and E/W — 49-40.8N 003-43.8W.

Wide berth requested

Keep well clear — or, when a distance is given ("TWO MILE BERTH REQUESTED"), at least that far away.

Cancellation reference

A line that cancels an earlier warning by its number, such as CANCEL HYDROLANT 1085/12.

HYDROLANT

The U.S. long-range warning series for Atlantic waters outside NAVAREA IV, including the eastern Atlantic, the Mediterranean and adjoining seas.

All warning terms →