Surveys

Underwater operations 20 oct thru 06 nov by shinkai 6500, mother ship and yokosuka in areas within three…

North Pacific Ocean · HYDROPAC 3327/23

What this record establishes

Archived notice · 2023-11-07 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 360/23 191201Z OCT 23.. Issued 2023-10-19 13:06Z. 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: North Pacific Ocean. The parsed report position is 28.370, 142.974. It is a position in the source message, not a live location. Check the original wording for limits and qualifications.

Current notices and reporting history in the North Pacific Ocean →

issued: 2023-10-19 13:06Z
status: Archived notice
self-cancels: 2023-11-07 00:01Z
authority: NAVAREA XI 360/23 191201Z OCT 23.
NAVAREA: NAVAREA XI · named as the source of this relay
sea: North Pacific Ocean
position: 28.370, 142.974
source: NGA MSI broadcast-warn JSON (archive, frozen 2024-05) · first seen 2026-08-17 13:38Z

Original warning text

PHILIPPINE SEA.
WESTERN NORTH PACIFIC.
JAPAN.
DNC 12.
1. UNDERWATER OPERATIONS 20 OCT THRU 06 NOV
   BY SHINKAI 6500, MOTHER SHIP AND YOKOSUKA
   IN AREAS WITHIN THREE MILES OF:
   A. 29-05.00N 144-00.00E.
   B. 28-00.00N 144-28.00E.
   C. 28-47.00N 142-42.00E.
   D. 28-14.00N 143-02.00E.
   E. 27-33.00N 143-00.00E.
   F. 28-34.27N 140-38.63E.
   WIDE BERTH REQUESTED.
2. CANCEL THIS MSG 070001Z NOV 23.

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.
Within a radius of: A circular area — every position within a stated distance of a point.
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.
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.

All warning terms →

Collected reports in this area · survey operations

39 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

Chichi shima, futami ko NR.3 light buoy, 27-04.9N 142-11.2E, L.LNav aids · 88 nm

Worldwide in the collected sources

56 survey operations listed in force · see all

Record snapshot 2026-09-28 08:10Z; 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.