Surveys

Survey operations in progress until further notice by M/V ramform tethys towing 8025 meter long cables in…

South Atlantic Ocean · HYDROLANT 1734/21

What this record establishes

Archived notice · 2021-07-26 10:22Z

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 VII 203/21 012002Z JUL 21.. Issued 2021-07-01 21:09Z. 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
2021-07-01 21:09Z
status
Archived notice
authority
NAVAREA VII 203/21 012002Z JUL 21.
NAVAREA
NAVAREA VII · named as the source of this relay
sea
South Atlantic Ocean
position
-7.938, 12.799
vessel
M/V RAMFORM TETHYS · 111 messages
source
NGA MSI broadcast-warn JSON (archive, frozen 2024-05) · first seen 2026-08-17 13:38Z

Original warning text

EASTERN SOUTH ATLANTIC.
ANGOLA.
DNC 01.
1. SURVEY OPERATIONS IN PROGRESS UNTIL FURTHER
   NOTICE BY M/V RAMFORM TETHYS
   TOWING 8025 METER LONG CABLES IN AREA BOUND BY
   08-22.4S 012-38.6E, 07-40.6S 012-23.6E,
   07-30.3S 012-57.0E, 08-11.4S 013-12.6E.
   SEVEN MILE BERTH REQUESTED.
2. CANCEL HYDROLANT 1664/21.

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 →

Collected reports in this area · survey operations

70 within 180 nm since 2004 · 2 in the last 12 months · 0 listed in force now

04
05
10
15
20
25
26

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

56 survey operations listed in force · see all

Record snapshot 2026-10-02 00:59Z; 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.