Survey operations 24 apr thru 01 may by M/V oceanic sirius towing 12 11112 meter long cables in area bound…
South Atlantic Ocean · HYDROLANT 1133/21
What this record establishes
Archived notice · 2021-05-02 00:01Z
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 178/21 232108Z APR 21.. Issued 2021-04-23 21:39Z. 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
- 2021-04-23 21:39Z
- status
- Archived notice
- authority
- NAVAREA V 178/21 232108Z APR 21.
- NAVAREA
- NAVAREA V · named as the source of this relay
- sea
- South Atlantic Ocean
- position
- -24.895, -39.836
- vessel
- M/V OCEANIC SIRIUS · 101 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-SOUTHEAST COAST. DNC 01. 1. SURVEY OPERATIONS 24 APR THRU 01 MAY BY M/V OCEANIC SIRIUS TOWING 12 11112 METER LONG CABLES IN AREA BOUND BY 26-47.47S 042-25.97W, 24-18.62S 042-21.21W, 24-18.80S 042-06.62W, 24-06.12S 042-06.45W, 23-31.55S 040-58.48W, 22-50.33S 039-56.13W, 22-35.07S 037-41.03W, 26-34.27S 037-35.21W. WIDE BERTH REQUESTED. 2. CANCEL HYDROLANT 1094/21. 3. CANCEL THIS MSG 02 MAY 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.
- 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.
- CANCEL THIS MSG
- The warning's own expiry: a line telling the reader when the message cancels itself.
Collected reports in this area · survey operations
629 within 180 nm since 2000 · 14 in the last 12 months · 3 listed in force now
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.
- Underwater operations in progress until 250259Z sep by M/V siem pilot in 22-25.32S 039-56.55W2026-09-18
- Underwater operations in progress until 240259Z sep by M/V siem pilot in 22-25.32S 039-56.55W2026-09-17
- Survey operations in progress until 030300Z nov by M/V fugro vaquita and an unmanned vessel along trackline…2026-09-12
- Survey operations in progress until 10 nov 27 by M/V rem saltire in area bound by 21-39.40S 039-49.11W,…2026-09-11
- Survey operations 07 thru 14 sep by M/V sanco spirit and M/V sea 1 dorado in areas bound by: a. 24-53.20S…2026-09-06
- Underwater operations 1000Z to 2000Z daily 01 thru 30 sep by M/V coral do atlantico in area bound by…2026-09-03
Month of issue in the collected archive
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
50 survey operations listed in force · see all
Record snapshot 2026-09-24 23:12Z; 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.