Surveys

Underwater operations 12 thru 22 apr by M/V shinkai 6500 and M/V yokosuka in areas bound by: a. 24-00N…

Philippine Sea · HYDROPAC 1059/21

What this record establishes

Archived notice · 2021-04-23 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 XI 117/21 071138Z APR 21.. Issued 2021-04-07 12:49Z. 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: Philippine Sea. 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 Philippine Sea →

issued: 2021-04-07 12:49Z
status: Archived notice
authority: NAVAREA XI 117/21 071138Z APR 21.
NAVAREA: NAVAREA XI · named as the source of this relay
sea: Philippine Sea
position: 20.838, 134.773
vessels: M/V SHINKAI · 19 messages M/V YOKOSUKA · 99 messages
source: NGA MSI broadcast-warn JSON (archive, frozen 2024-05) · first seen 2026-08-17 13:38Z

Original warning text

PHILIPPINE SEA.
JAPAN.
DNC 11, DNC 12, DNC 23.
1. UNDERWATER OPERATIONS 12 THRU 22 APR
   BY M/V SHINKAI 6500 AND M/V YOKOSUKA
   IN AREAS BOUND BY:
   A. 24-00N 135-00E, 27-00N 135-00E,
      27-00N 137-30E, 24-00N 137-30E.
   B. 13-00N 131-30E, 17-00N 131-30E,
      17-00N 135-20E, 13-00N 135-20E.
   ALTERNATE, IN AREAS BOUND BY:
   C. 23-00N 137-30E, 26-00N 137-30E,
      26-00N 140-00E, 23-00N 140-00E.
   D. 20-50N 131-00E, 23-00N 131-00E,
      23-00N 136-00E, 20-50N 136-00E.
   E. 26-30N 131-00E, 27-30N 131-00E,
      27-30N 133-30E, 26-30N 133-30E.
   WIDE BERTH REQUESTED.
2. CANCEL THIS MSG 23 APR 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.
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.

All warning terms →

Collected reports in this area · survey operations

11 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.

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

55 survey operations listed in force · see all

Record snapshot 2026-10-02 06:37Z; 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.