Two sailors rescued off Costa Rica after their sailboat sank. They were in a small inflatable for three days. I don't know what kind of GPS/beacon they had -- seems like they could only signal for help now and again. They didn't seem to have any other gear at all.

"But they did have the GPS unit, which allowed them to signal for help every four hours. After three days with no sign of help, they were beginning to wonder if it was working.

It turned out, however, that the signal was picked up by Coast Guard officials in Victoria, who relayed the information to U.S. crews."

Links:

http://www.vancouversun.com/news/canada/rescued+after+ordeal+adrift+Pacific/3994845/story.html

http://www.cbc.ca/canada/british-columbia/story/2010/12/17/bc-costa-rica-sailboat-rescue.html