Perhaps more remarkably, Hackett has received 3,100 responses from all over the world.
"I started this hobby in May of 1996," Hackett told a BBC video crew. So far, he has received responses from "Africa, Russia, Holland, different parts of the United Kingdom, Great Britain, Paris, France, Scotland, all different parts of Ireland, British Isles, different parts of South America, from Rhode Island, I got from Maine, Boston, Orlando, Florida, New Hampshire, all different parts of Quebec, Nova Scotia, New Brunswick, Madeleine Islands, and even some here in P.E.I."
Hackett said he "never dreamt I'd get that many back." He showed some of the responses he's gotten to the BBC. One person sent him a DVD. Another told him about sons who had drowned. Many of the messages take several years to return to him. He doesn't put his phone number on the notes he sends out, because he wants to be able to hold on to people's responses.
"Every letter got his own story," he said.
Hackett puts his messages in empty juice bottles, and he dates each of his messages, which are printed on colored paper.
"The wind got to be west, west or south west" in order to carry the bottles out to sea, Hackett said. "Once they got out there I'd say about seven or eight miles off, then they go all different directions with the tide."
Depending on the wind, Hackett sends between zero and 200 bottles off every week. He doesn't think he will ever stop.