Depth sounder

A depth sounder is an electronic instrument that measures the depth of water beneath a boat using sound waves (sonar). The instrument displays the depth on a screen or gauge. Charter guests typically encounter depth sounders when navigating to anchorages, mooring fields, or approaching shallow waters. The depth sounder provides critical safety information, alerting skippers to shallow areas and helping determine suitable anchorage locations. Most modern yachts have integrated chartplotters that display depth data alongside GPS navigation.