Pouring rain and a thick mist Saturday failed to dampen the enthusiasm of hunters hoping to win a half-million-dollar reward in the first major search for the Loch Ness monster in three years.

But there was no immediate sign of the legendary beast.National oddsmakers at the William Hill Organization Ltd. have put up the cash - 250,000 pounds, or $477,500 - for the first person or team to discover "conclusive evidence" of the creature's existence.

Based at the village of Drumnadrochit near the northern shore of the loch - or lake - in the Scottish Highlands, four groups are taking part in the two-day search. They range from serious contestants to publicity seekers.

William Hill has offered an additional $2,865 prize for the best search method.

Daniel Isted, the 25-year-old London-based editor of a corporate in-house magazine, said he was using what he called "crystal divination." He said a tourmaline crystal, suspended from a yacht over the inky waters, would swing to indicate Nessie's direction.

Former rock singer Screaming Lord Sutch, head of a political group called the Monster Raving Loony Party, said his secret weapon was a whistle that produces the mating call of monsters.

Tongue in cheek, he announced he would use haggis - a Scottish delicacy consisting of chopped entrails and oatmeal cooked in the lining of a sheep's stomach - as bait to lure the creature to the surface.

The Raving Loony Party, created to poke fun at politicians, runs candidates in most elections.

Andy Gray, 38-year-old managing director of a Scottish company that supplies underwater sonar equipment for the North Sea oil industry, is taking a more scientific approach with a sophisticated underwater radar.

"Typically this system can work 3,280 feet beneath the sea. If Nessie comes within our search scan we will find it."

Loch Ness is 754 feet deep, 23 miles long and a mile wide.

Iain Bishop, deputy keeper of the zoology department of the Natural History Museum in London, will examine any evidence found on behalf of the oddsmakers.

Standing in the pouring rain and looking out at the mist-covered lake, he acknowledged some skepticism.

"I don't expect to be overwhelmed by it (evidence)," Bishop said.

Locals, who have seen it all before, picked their way through the army of news people and television crews from the United States, Japan, France, Britain and elsewhere that have invaded the village.

The legend of the Loch Ness Monster dates from A.D. 565 when St. Columba castigated the creature for attacking a follower.

In modern times there have been more than 4,000 reported sightings, including the October 1987 sighting that spawned the last major hunt.

That search, Operation Deepscan, used sonars and reported detecting what was called a large "fish-like arch" at a depth of 450 feet on the southern end of the lake.

Deepscan spokesman Guy Pearse said then the object registered as a clear, large blip on the sonar but when the same boat scanned the area again the object had disappeared.

Skeptics have explained away the sightings as everything from waves, logs and rotting vegetation to otters, swimming deer and overindulgence in Scottish whisky.

A study by a Scottish company, Mackay Consultants, printed in The Times of London in May, said the Loch Ness Monster was worth $47 million a year in tourist revenue and responsible for 2,500 tourist industry jobs.

It said half a million visitors a year from all over the world come to Loch Ness in hopes of seeing the fabled creature.