I know you’ve seen it too, probably in movies or cartoons and thought how futile could it be, that a castaway sends a bottle floating into the ocean hoping someone will find it and save him. Harold Hackett tried to find out if this actually works.
Since 1996 he is throwing bottles into the Atlantic ocean from the US, and has currently thrown over 4,800 bottles asking for a response back. The result. He has got over 3,100 responses from all over the Atlantic including The Bahamas, Africa, France, Germany etc.
In some cases, bottles ended up in Norway and Ireland, and according to tracking numbers he asked in order to be included in his response, they took 11 years to reach the shore.
Statistically speaking, throwing a bottle into the ocean gives you a 60% chance to get your message across. If you have 5 or more bottles it is, then, mathematically certain that one will reach the other party fast.