People were talking 1,000 meters, and that would have been nearly impossible, but 35 meters (~110 feet) I can totally believe from a large ship. It is still probably a significant shot in that the lifeboat was bobbing. A kill is a kill.
With the pitch and roll of the ship & likewise the target boat and the unanticipated movement of the targets themselves 3 separate head shots from 35 feet would be amazing!!