You can customize how the map appears in marine mode.

Hold MENU, and select Settings > Map > Marine.

Marine Chart Mode

Enables the nautical chart when displaying marine data. This option displays various map features in different colors so the marine POIs are more readable, and so the map reflects the drawing scheme of paper charts.

Spot Soundings

Enables depth measurements on the chart.

Light Sectors

Shows and configures the appearance of light sectors on the chart.

Symbol Set

Sets the chart symbols in marine mode. The NOAA option displays the National Oceanic and Atmospheric Administration chart symbols. The International option displays the International Association of Lighthouse Authorities chart symbols.