searches out of Bermuda for one of the world's leading solo yachtsmen lost at sea.

A C-130 Coast Guard airplane is flying into Island this morning to bolster the search for Mr. Mike Plant, who was sailing to France from New York City aboard a 60-foot sloop called Coyote .

The search began in earnest yesterday afternoon when the Coast Guard C-130 refuelled in Bermuda and then flew to the search area, about 1,000 miles east northeast of the Island.

Last night, a Canadian Forces Hercules out of Nova Scotia conducted a flare search for the 42-year-old sailor.

The drama began on October 27 when an emergency radio (EPIRB) signal was recorded by the Canadian Coast Guard in Goose Bay, Labrador. But it was unable to locate its source.

The Canadians filed the signal with the US Coast Guard because it was outside their search area. The Americans then issued a cross-ocean bulletin asking all vessels for any information on the signal.

"We contacted pretty well everything that floats between here and London,'' a Coast Guard spokesman from New York said yesterday.

But it wasn't until Wednesday when a friend of Mr. Plant's helped with a computer search for Coyote's EPIRB signal that the air search was launched.

Last night, a US Coast Guard spokesman said the 18-day delay between the EPIRB signal and yesterday's search was due to the fact that Mr. Plant's EPIRB had not been registered and to the inadequate signal received at the Goose Bay listening post.

The spokesman said a passing satellite registered three beeps from the EPIRB, one short of the four necessary for Goose Bay computers to interpret "anything meaningful.'' Then on Wednesday Mr. Plant's friend, concerned the sailor had not arrived in France, contacted Canadian authorities.

The friend had Mr. Plant's EPIRB code and the Canadians traced it in the computer records to the October 27 signal.

"That's the reason for the time delay,'' the Coast Guard spokesman said.

"That's why we weren't launching airplanes.'' Reports indicate Mr. Plant's boat had experienced a breakdown in her main electrical system. On October 21, he radioed a nearby tanker saying he'd lost electrical power and was hand-steering his boat. He did not ask for assistance and said he was continuing his sail to France.

Last night, the Coast Guard spokesman said officials would evaluate the search effort tonight for a decision on whether to continue or not.

Mr. Plant has participated in two BOC challenge races, one of the oldest single-handed races, with four stopovers around the world. In the 1987-88 contest, he won his class.

The sailor was heading to France for the start of the Vendee Global Challenge, a single-handed, non-stop, round-the-world race to start on November 22.

Yesterday's search was just one incident in a busy week for Harbour Radio.

On Thursday, Harbour Radio linked an ocean-going New Zealand ship with a US medical service that helped diagnose an ailing crewman.

The 153-foot San Arawa radioed for assistance early Thursday. It reported the 63-year-old crewman in pain from swelling and bumps to the head.

Harbour Radio set up a link with the US-based Medical Advisory Service which tentatively concluded the man was suffering an attack of shingles, an inflammatory virus that causes pain and swelling.

San Arawa , with a crew of nine, was en route to New Zealand from Norway via the Panama Canal. She is to put into either Santo Domingo or St. Thomas for assistance.

Harbour Radio also reported that a 53-foot ketch with five people aboard has not been heard from since her departure from Virginia on November 4.

The Free Union was heading to St. Thomas in the US Virgin Islands with a possible stop in Bermuda.

Efforts continued last night to establish communication with the boat.