Underwater operations 151800Z to 271800Z oct in area bound by 38-55N 009-15E, 38-45N 009-15E, 38-45N…
Mediterranean Sea - Western Basin · HYDROLANT 2536/21
What this record establishes
Archived notice · 2021-10-27 19:00Z
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 III 751/21 141206Z OCT 21.. Issued 2021-10-14 14:13Z. 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
- Mediterranean Sea - Western Basin. 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
- Platform ss victoria established in 24-37.75S 042-31.18Wcancelled by this notice
Current notices and reporting history in the Mediterranean Sea - Western Basin →
Activity windows · 1 in this warning
| opens (UTC) | closes (UTC) | local | length |
|---|---|---|---|
| 2021-10-15 18:00Z | 2021-10-27 18:00Z | — | 288 h |
Parsed from the warning text; outside these windows the area is normally not active, but the warning stays in force until cancelled.
- issued
- 2021-10-14 14:13Z
- status
- Archived notice
- self-cancels
- 2021-10-27 19:00Z
- authority
- NAVAREA III 751/21 141206Z OCT 21.
- NAVAREA
- NAVAREA III · named as the source of this relay
- sea
- Mediterranean Sea - Western Basin
- position
- 38.834, 8.762
- source
- NGA MSI broadcast-warn JSON (archive, frozen 2024-05) · first seen 2026-08-17 13:38Z
Original warning text
WESTERN MEDITERRANEAN SEA. TYRRHENIAN SEA. SARDINIA. DNC 08. 1. UNDERWATER OPERATIONS 151800Z TO 271800Z OCT IN AREA BOUND BY 38-55N 009-15E, 38-45N 009-15E, 38-45N 008-18E, 38-55N 008-15E. 2. CANCEL HYDROLANT 2533/21. 3. CANCEL THIS MSG 271900Z OCT 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.
- Underwater operations
- Divers or remotely operated vehicles are working below a vessel that cannot easily move out of the way.
- Date-time group (DTG)
- A compact UTC timestamp — day, hour and minute followed by Z — such as 201500Z for the 20th at 15:00 UTC.
- 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.
- 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
156 within 180 nm since 1998 · 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 30 oct by vessel anteos in 39-19.79N 007-50.60E2024-09-03
- Survey operations in progress until 30 jun by M/V ng driller along trackline joining 39-13.99N 007-49.47E,…2024-04-24
- Survey operations in progress until 30 aug by M/V durable along trackline joining 41-22.68N 006-04.83E,…2024-04-24
- Survey operations in progress until 15 apr by M/V ng driller in: a. 39-13.99N 007-49.48E2024-02-01
- Survey operations 20 aug thru 17 sep by M/V dallaporta in area bound by 40-38.53N 010-05.00E, 41-20.54N…2022-08-18
- Survey operations 08 thru 30 jun by M/V mg worker in area bound by 39-20.63N 008-17.09E, 39-20.63N…2022-06-07
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
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 2026-10-01 22:25Z; 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.