In Notices to Mariners (NtM), the term “command types” usually refers to the standard correction commands / instructions used when applying chart corrections. These tell the navigator exactly what action to take on the chart. The main command types of Notice to Mariners corrections are: ⸻ 1. Insert • Meaning: Add new information to the chart. • Examples: • Insert light characteristic • Insert depth, note, symbol, or legend • Chart Action: Write neatly in ink (or pencil if T&P). ⸻ 2. Delete • Mea