Surveys

Survey operations in progress until 15 jul by M/V astrea in area bound by 37-25.7N 012-35.8E, 37-25.7N…

Mediterranean Sea - Eastern Basin · HYDROLANT 1535/21

What this record establishes

Archived notice · 2021-07-16 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 III 508/21 081222Z JUN 21.. Issued 2021-06-08 12:46Z. 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 - Eastern 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

Current notices and reporting history in the Mediterranean Sea - Eastern Basin →

issued
2021-06-08 12:46Z
status
Archived notice
authority
NAVAREA III 508/21 081222Z JUN 21.
NAVAREA
NAVAREA III · named as the source of this relay
sea
Mediterranean Sea - Eastern Basin
position
37.366, 12.825
vessel
M/V ASTREA · 5 messages
source
NGA MSI broadcast-warn JSON (archive, frozen 2024-05) · first seen 2026-08-17 13:38Z

Original warning text

STRAIT OF SICILY.
SICILY.
DNC 09.
1. SURVEY OPERATIONS IN PROGRESS UNTIL 15 JUL
   BY M/V ASTREA IN AREA BOUND BY
   37-25.7N 012-35.8E, 37-25.7N 013-03.1E,
   37-18.2N 013-03.1E, 37-18.2N 012-36.0E.
   ONE MILE BERTH REQUESTED.
2. CANCEL HYDROLANT 1491/21.
3. CANCEL THIS MSG 16 JUL 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.
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.

All warning terms →

Collected reports in this area · survey operations

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

99
00
05
10
15
20
24

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 2026-10-01 23:03Z; 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.