Underwater operations 20 thru 27 mar by M/V shinkai 6500 and M/V yokosuka in areas bound by: a. 28-33.5N…
Philippine Sea · HYDROPAC 874/21
What this record establishes
Archived notice · 2021-03-28 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 88/21 191205Z MAR 21.. Issued 2021-03-19 14:01Z. 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
- 2021-03-19 14:01Z
- status
- Archived notice
- authority
- NAVAREA XI 88/21 191205Z MAR 21.
- NAVAREA
- NAVAREA XI · named as the source of this relay
- sea
- Philippine Sea
- position
- 26.700, 141.083
- vessels
- M/V SHINKAI · 19 messagesM/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 12.
1. UNDERWATER OPERATIONS 20 THRU 27 MAR
BY M/V SHINKAI 6500 AND M/V YOKOSUKA
IN AREAS BOUND BY:
A. 28-33.5N 140-38.0E, 28-35.0N 140-38.0E,
28-35.0N 140-39.0E, 28-33.5N 140-39.0E.
B. 26-41.0N 141-04.0E, 26-43.0N 141-04.0E,
26-43.0N 141-06.0E, 26-41.0N 141-06.0E.
WIDE BERTH REQUESTED.
2. CANCEL THIS MSG 28 MAR 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.
Collected reports in this area · survey operations
35 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.
- Underwater operations 04 thru 21 may by submersible shinkai 6500 and M/V yokosuka in area bound by 28-22.00N…2024-05-03
- Underwater operations 20 oct thru 06 nov by shinkai 6500, mother ship and yokosuka in areas within three…2023-10-19
- Underwater operations 11 thru 13 mar by M/V yokosuka with submersible shinkai 6500 in area bound by 26-10N…2022-03-06
- Underwater operations 12 thru 28 may by submersible shinkai 6500 and M/V yokosuka in areas bound by: a.…2021-05-11
- Underwater operations 06 thru 12 mar by M/V shinkai 6500 and M/V yokosuka in area bound by 28-15N 142-00E,…2021-03-05
- Survey operations 162300Z to 181500Z dec by M/V kairei towing 1300 meter long cables in area bound by 28-05N…2020-12-16
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
- Discoloured water observedVolcanic · 32.8 nm
- 080200UTC issued at 080200UTC sep 2026 volcanic warning volcano name:nishino shima LOCATION:27-14.6N…Volcanic · 34.4 nm
- Discoloured water observed in extending south for 5 miles, 2 mile wide, from 27-16.7N 140-56.6E at 120643Z octVolcanic · 35.5 nm
- Chichi shima, futami ko NR.3 light buoy, 27-04.9N 142-11.2E, L.LNav aids · 63.4 nm
- Discoloured water observed in vicinity of 25-27.1N 141-14.5E at 140425Z junVolcanic · 75.4 nm
- Discoloured water observed in vicinity of 24-48.8N 141-19.2E at 130800Z julVolcanic · 114 nm
- Volcanic activity reported at io-to in vicinty of 24-45.00N 141-17.3EVolcanic · 117.6 nm
Worldwide in the collected sources
50 survey operations listed in force · see all
Record snapshot 2026-09-24 22:07Z; 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.