navigational instrument used to measure the depth of a body of water (as by ultrasound or radar)

navigational instrument used to measure the depth of a body of water (as by ultrasound or radar)

navigational instrument used to measure the depth of a body of water (as by ultrasound or radar)

an instrument that measures the height above ground; used in navigation

an instrument that measures the height above ground; used in navigation

an instrument that measures the height above ground; used in navigation

an instrument that measures the altitude and azimuth of celestial bodies; used in navigation

an instrument that measures the altitude and azimuth of celestial bodies; used in navigation

a unit of length used in navigation; exactly 1,852 meters; historically based on the distance spanned by one minute of arc in latitude

a unit of length used in navigation; exactly 1,852 meters; historically based on the distance spanned by one minute of arc in latitude