The light weight, easy to wear waterproof, multi-function wristwatch has a built-in radio transmitter which when activated either manually or automatically, immediately transmits a distress tone on the international emergency search and rescue frequency (121.5 MHz). The distress signal transmitted can be detected by a surface rescue vessel or helicopter, which can accurately home in to the watch using direction-finding equipment. The unit is a working watch, fully waterproof to a depth of 50 mtr and can be set to manual or automatic activation on immersion in water, making it functional and easy-to wear manoverboard transmitter for crew members.