Surveys

Underwater operations in progress until further notice in area bound by 45-50.8S 059-53.7W, 45-53.2S…

South Atlantic Ocean · HYDROLANT 995/18

What this record establishes

Archived notice · 2018-03-25 02:12Z

This notice comes from the historical archive. Its archived status does not establish when or how the reported situation ended.

Source and dates
NGA MSI broadcast-warn JSON (archive, frozen 2024-05) · NAVAREA VI 152/18 231640Z MAR 18.. Issued 2018-03-23 16:58Z. First collected 2026-08-17 13:38Z; last seen in collection 2026-08-17 15:46Z. Collection dates record ingestion, not a new incident or a fresh field observation.
Location covered
South Atlantic Ocean. The map shows an area described by the warning; the listed coordinate is its representative center. Check the original wording for limits and qualifications.

Related notices and cancellation links

Current notices and reporting history in the South Atlantic Ocean →

issued
2018-03-23 16:58Z
status
Archived notice
authority
NAVAREA VI 152/18 231640Z MAR 18.
NAVAREA
NAVAREA VI · named as the source of this relay
sea
South Atlantic Ocean
position
-45.966, -59.819
source
NGA MSI broadcast-warn JSON (archive, frozen 2024-05) · first seen 2026-08-17 13:38Z

Original warning text

WESTERN SOUTH ATLANTIC.
DNC 07.
1. UNDERWATER OPERATIONS IN PROGRESS
   UNTIL FURTHER NOTICE IN AREA BOUND BY
   45-50.8S 059-53.7W, 45-53.2S 059-40.0W,
   46-05.0S 059-44.3W, 46-02.6S 059-58.5W.
   FOUR MILE BERTH REQUESTED.
2. CANCEL HYDROLANT 988/18.

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.
Underwater operations
Divers or remotely operated vehicles are working below a vessel that cannot easily move out of the way.
Until further notice
The operation or danger has no scheduled end; the warning stays in force until a later message cancels it.
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 →

Collected reports in this area · survey operations

57 within 180 nm since 2001 · 0 in the last 12 months · 0 listed in force now

01
05
10
15
18

Counts include repeat notices about the same situation. NGA archive coverage ends 2024-05; live collection began 2026-08-17. The period between them is incomplete. An empty year is not evidence that no hazards occurred.

Month of issue in the collected archive

J
F
M
A
M
J
J
A
S
O
N
D

All available years combined. Uneven collection and repeat bulletins affect these counts; this chart does not measure the seasonality or probability of incidents.

Nearby notices listed in force · within 120 nm

No other collected notice is currently listed in force within this radius. This does not establish safe conditions.

Worldwide in the collected sources

55 survey operations listed in force · see all

Record snapshot 2026-10-02 06:11Z; source collection times vary.

Surveys

Hydrographic and scientific survey vessels, often towing long arrays. All current survey operations →

Not for navigation. This is a re-rendering of an official navigational warning for awareness; mariners must use official NAVAREA broadcasts and their national MSI service.