Surveys

Survey operations in progress until 20 feb 18 by M/V ramform tethys and M/V thor modi towing 16 8100 meter…

South Atlantic Ocean · HYDROLANT 3536/17

What this record establishes

Archived notice · 2018-02-07 22:49Z

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 V COASTAL N 888/17 010025Z NOV 17.. Issued 2017-11-01 02:16Z. 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.

Current notices and reporting history in the South Atlantic Ocean →

issued
2017-11-01 02:16Z
status
Archived notice
authority
NAVAREA V COASTAL N 888/17 010025Z NOV 17.
NAVAREA
NAVAREA V · named as the source of this relay
issued by
NAVAREA V COASTAL N
sea
South Atlantic Ocean
position
-4.133, -36.802
vessels
M/V RAMFORM TETHYS · 111 messagesM/V THOR MODI · 4 messages
source
NGA MSI broadcast-warn JSON (archive, frozen 2024-05) · first seen 2026-08-17 13:38Z

Original warning text

WESTERN SOUTH ATLANTIC.
BRAZIL-NORTH COAST.
DNC 01.
1. SURVEY OPERATIONS IN PROGRESS UNTIL 20 FEB 18
   BY M/V RAMFORM TETHYS AND M/V THOR MODI TOWING
   16 8100 METER LONG CABLES IN AREA BOUND BY
   03-36.0S 037-19.3W, 03-35.3S 037-18.7W,
   03-35.4S 037-05.5W, 03-35.4S 036-59.5W,
   03-41.1S 036-59.5W, 03-44.6S 036-55.8W,
   03-44.5S 036-31.9W, 03-50.2S 036-25.6W,
   04-00.7S 036-24.6W, 04-04.2S 036-20.9W,
   04-07.2S 036-12.3W, 04-15.2S 036-03.9W,
   04-48.5S 036-03.9W, 04-47.6S 036-12.8W,
   04-45.3S 036-20.3W, 04-42.7S 036-27.8W,
   04-35.7S 036-52.6W, 04-30.9S 036-58.6W,
   04-23.0S 037-07.1W, 04-09.7S 037-07.1W,
   03-58.6S 037-28.5W, 03-51.5S 037-36.1W,
   03-39.6S 037-48.4W, 03-27.3S 037-35.3W,
   03-35.3S 037-27.7W, 03-36.0S 037-27.0W.
   WIDE BERTH REQUESTED.
2. CANCEL THIS MSG 21 FEB 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.
Survey operations
A research or survey vessel is mapping the seabed or water column, often while towing equipment.
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.
CANCEL THIS MSG
The warning's own expiry: a line telling the reader when the message cancels itself.

All warning terms →

Collected reports in this area · survey operations

92 within 180 nm since 1999 · 0 in the last 12 months · 0 listed in force now

99
00
05
10
15
20
23

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

Worldwide in the collected sources

56 survey operations listed in force · see all

Record snapshot 2026-10-03 03:08Z; 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.