In 1973 a worker on a Dutch rig in the North Sea fell several stories onto a steel deck. The injuries were so severe that his brain was exposed, and he was in a deep coma. The rig called for emergency helicopter evacuation because the typical rig boat would surely kill him during the run to shore that would take several hours. WX was literally zero-zero, with no lift forecast until the next day. There was no breeze and the sea was relatively calm, with a long greasy swell.
Capt Hans Zeedyke launched a KLM S61 from Schiphol with its normal crew and a doctor who had been scrambled from an Amsterdam hospital. He found the rig on radar and identified it by passing overhead, using the ADF swing to be sure he had the right one. He lined up 5 miles out at 100 feet, using the radar and a steady 80 knots, 100 feet above the waves on the rad alt. He timed the range rings with a stop watch, so that he knew precisely how many seconds the last 1/2 mile ring would consume as the radar became unusable, and he had the rig launch a rig boat with a hand-held radio to sit and wait 1/4 mile out on his inbound bearing. The boat was to let him know when he passed overhead, so that he could flare to a hover in time to avoid the rig. He never saw the rig boat, but as he heard the boat's call, he raised the nose a few degrees and concentrated on the speed, altitude and heading, gradually beeping the cyclic into a trimmed hover. As the aircraft came nose down in a 15 knot running hover, the CP called out that one leg of the rig was in sight. He stabilized the hover on that leg - which was the only thing in sight besides the gray swells and the fog - and then raised the collective slowly to climb up to deck height. As the deck came past the windshield, he slowly tilted the nose a bit, came over the deck and then landed. He told me that his legs were shaking so badly, he had trouble setting the brakes.
The crew gathered the stretcher and patient, and they made an ITO off the rig within minutes. The ILS at Amsterdam and patient transfer were uneventful. The patient recovered, with a big plate in his head, of course.
All the crew were awarded the Sikorsky Winged S in a ceremony at KLM later that year.