If I'm reading all this correctly, the CG got notified by the mariner calling on the radio that he was aground. The in-route helo could not find him without direction-finding his radio transmission, indicating that he did not know where he was. I would guess that "not knowing where you are" is probably the leading cause for grounding. Shame about the boat.
As
@Gunni notes, this happened just before dawn. But still, it hard to imagine his S.A. being so far off that he did not know what he hit. Obviously the lighthouse was there. There are three on the top side of the Keweenaw. There is data to support he thought he was 25 miles farther east.
From the local news:
EAGLE RIVER — An unidentified 73-year-old man was rescued Saturday morning after his sailing vessel went aground on Manitou Island, approximately three miles from the eastern tip of Keweenaw Point in Lake Superior.
At 5:30 a.m. Saturday, Coast Guard Sector Sault Ste. Marie Command Center received a mayday call from the sailboat pilot, stating the boat had gone aground on the rocks, according to a news release from the U.S. Coast Guard.
The command center immediately launched a MH-60 helicopter from Air Station Traverse City, the report stated.
At 6:15 a.m., the Keweenaw County Sheriff’s Office received a dispatch stating a vessel had gone aground somewhere in the Eagle Harbor area, which is roughly 25 miles west of Copper Harbor.
Sheriff Bill Luokkanen said his office launched its boat and patrolled the coastline between Eagle River and Copper Harbor three times, but saw no sign of a wrecked boat.
The Coast Guard helicopter established communication with the pilot of the grounded boat at 8:35 a.m. and employed direction-finding radio equipment to locate the vessel. The helicopter deployed a rescue swimmer, who assisted the distressed mariner, and hoisted him to safety. The man was then transported to emergency services at an undisclosed facility.