Survey operations in progress until 01 may by M/V ramform tethys and M/V thor modi towing 16 8100 meter long…
South Atlantic Ocean · HYDROLANT 941/18
What this record establishes
Archived notice · 2018-04-13 19:32Z
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 228/18 191714Z MAR 18.. Issued 2018-03-19 17:22Z. 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
- Cancel HYDROLANT 941/18 and this msglater cancellation notice
Current notices and reporting history in the South Atlantic Ocean →
- issued
- 2018-03-19 17:22Z
- status
- Archived notice
- authority
- NAVAREA V COASTAL N 228/18 191714Z MAR 18.
- 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 01 MAY 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 02 MAY 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.
Collected reports in this area · survey operations
92 within 180 nm since 1999 · 0 in the last 12 months · 0 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.
- Survey operations in progress until 182300Z may in areas bound by: a. 02-56.00S 038-00.20W, 02-56.00S…2023-05-18
- Underwater operations 0800Z to 2100Z daily 05 sep thru 05 mar 23 by M/V paracuru in 04-52.42S 036-22.45W2022-09-05
- Underwater operations 1100Z to 1900Z daily 15 thru 22 jun by M/V texas and M/V seamaster I in 05-42.08S…2021-06-14
- Underwater operations 1100Z to 1900Z daily 01 thru 06 jun by M/V texas and M/V seamaster I in 05-42.08S…2021-05-31
- Survey operations in progress 0800Z to 1700Z daily until 23 jul by M/V raisa II in area bound by 03-43.71S…2020-07-17
- Survey operations in progress until 15 apr by M/V ocean dream and M/V bgp pioneer eco warrior each towing…2020-03-16
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
- Odas buoy bravo rn-l temporarily established until 20 oct in 04-53.00S 035-46.01WNav aids · 76.6 nm
- Odas buoy established in 05-09.46S 035-09.81WNav aids · 115.8 nm
Worldwide in the collected sources
55 survey operations listed in force · see all
Record snapshot 2026-09-26 09:23Z; 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.