A man adrift for 106 days after being lost at sea in a small boat credits a six foot shark with alerting him to the presence of his eventual rescuers. I have heard of dolphins coming to the aid of desperate seafarers, but sharks? It's usually the other way around. Stories told of sharks tend to focus on them speeding up the demise of ill-fated sailors, not aiding in their rescue. I guess there is always a first time for anything.