SOS sub watch

Hi, my name is Giuseppe Vullo and i’m a business owner, lover of underwater fishing and i would to achieve a product related to this sport which is not present in the market. My idea is about an underwater watch with the particularity of being able to send a help message to another clock that is previously synchronized (useful in dangerous situations, catch fish, general help). This idea was born, in fact, when a my friend who was fishing with me, he was in danger and did not know what to call me.