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COMDTINST M16500.21A — AIDS TO NAVIGATION MANUAL - SEAMANSHIP

COMDTINST M16500.21A is listed as current Current
in the USCG Directives catalog as of our last index refresh (2026-10-05). Status is mirrored from that catalog, re-checked weekly — every change is logged. Note: its publication date is 2012-03-02 — 14.6 years old — so check for newer interim changes before citing it.

Download PDF Official document (USCG Directives)

Branch	U.S. Coast Guard
Series	COMDTINST M
Publication date	2012-03-02 (14.6 years ago)
Status	Current
Proponent / OPR	CG-751
Source of record	USCG Directives

Version history

Changes we observed

Our weekly check on 2026-09-21 saw status archived → current
Our weekly check on 2026-09-18 saw status current → archived

These are dated observations from our own catalog refresh — when we saw the record change, which the publisher does not record.

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Get an email if COMDTINST M16500.21A is revised, superseded, or rescinded.

Nearby in the COMDTINST M series

COMDTINST M16500.17 — ALTERNATING CURRENT AIDS TO NAVIGATION SERVICING GUIDE Not in the current catalog
COMDTINST M16500.19C — SHORT RANGE AIDS TO NAVIGATION SERVICING GUIDE Not in the current catalog
COMDTINST M16500.2 — HYDROGRAPHIC MANUAL, 4TH ED (NOAA) Not in the current catalog
COMDTINST M16500.24 — SOLAR DESIGN MANUAL Not in the current catalog
COMDTINST M16500.25A — AIDS TO NAVIGATION MANUAL - STRUCTURES Not in the current catalog

This is an unofficial index built from the public catalog. The controlling copy is always the one on USCG Directives — verify there before citing COMDTINST M16500.21A in an official product.