NOAA Electronic Navigational Charts - Display of Isolated Shoal Soundings
Mariners are advised that ECDIS may not display some isolated shoal depths when operating in “BASE or STANDARD Display” mode. Route planning and monitoring alarms for these shoal depths may not always be activated. To ensure safe navigation and to confirm that a planned route is clear of such dangers, mariners should visually inspect the planned route using the ECDIS configured to display “ALL DATA”. The Mariner should not solely rely on the automated voyage planning check function. NOAA has updated the following ENC’s to resolve this issue.