: They are primarily used with OpenCPN , but also work with other software like Locus Map . Note that version 3 (v3) of CM93 is encrypted and generally not supported by open-source tools.

For cruising sailors, (paid, but very affordable) offers updated vector maps for OpenCPN. Alternatively, some navigators use raster chart collections that are legally released by hydrographic offices.

: CM93 v2 charts are outdated . C-MAP ceased official updates for the v2 format years ago in favor of newer, encrypted versions. They should be used for situational awareness and planning, but not as your primary means of navigation in restricted waters where recent hydrographic changes (like shifted sandbars or new buoys) are critical.