acoustic buoy

English Thesaurus

1. a buoy that can be heard (at night) (noun.communication)

hypernym	:	buoy,
definition	:	bright-colored; a float attached by rope to the seabed to mark channels in a harbor or underwater hazards (noun.communication)

hyponym	:	bell buoy, gong buoy,
definition	:	a buoy with a bell on it (noun.communication)

hyponym	:	whistle buoy, whistling buoy,
definition	:	a buoy that makes a whistling noise (noun.communication)