Show submarine signal system adopted the united states lighthouse board has decided to extend the submarine signal system to a number of import ant lightships on the atlantic coast as a result of tests made the past summer the submarine bell and its operation were fully described in the august 1905 popular mechanics sig nals transmitted and read as tar as 15 the lightship sounds its number on a submarine bell hung over the side of the ship at a depth of 15 or 20 feet the navigator re ceiling the signal locates the light ship by aeten leten au tc its aber on his chart |