SLAPTON SANDS, England (AP) _ For American veteran Manny Rubin, it was like a funeral, a chance after 43 years to lay to rest the memories of a fiery sea full of bodies of young soldiers and sailors.

For local hotel owner Ken Small, it was a tearful end to a 16-year campaign for a memorial to the 749 Americans who died in the English Channel during a dry-run for D-Day that turned into a disastrous encounter with German E-boats.

For the official U.S. and British representatives, it was a time to remember not just the 749 who perished in one of the forgotten tragedies of World War II but all those who died fighting for the freedom and peace the West enjoys today.

A crowd of 300 Americans and Britons huddled together in driving rain Sunday overlooking the slate gray waters where the GIs died. They prayed, sang hymns and witnessed the unveiling of a memorial to their sacrifice.

Rep. Beverly Byron, D-Md., who sponsored the congressional resolution authorizing the memorial, and Peggy Verniquet, chairman of the local South Hams District Council, pulled an American flag off the memorial plaque, cast in Colorado and mounted on a boulder of Devon granite.

''May these men rest in the knowledge that the lessons in this tragedy added significantly to the ability of the Allies to carry out the successful invasion of Normandy on June 6, 1944,'' it read.

A lone U.S. Army bugler played Taps, and as the 40-minute ceremony ended, Small, teary-eyed and unable to speak, placed his own poppy wreath in front of the memorial.

''I gave 16 years. These young men gave their lives. May they forever rest in peace,'' said a handwritten card on Small's wreath.

The former Royal Air Force corporal laid a similar wreath a few yards away at an American Mark V Sherman tank that sank during Exercise Tiger. He recovered it in 1984 as his own personal memorial to the men.

The three-day exercise began April 26, 1944, as a mock assault by 30,000 Americans on Slapton Sands, chosen because it resembled Utah Beach on the Normandy coast where the American D-Day landings were planned.

But nine German E-boats torpedoed three amphibious landing ships and in the confusion some Americans fired on their own comrades. Hundreds of others were found the following morning, floating upside down in the water because they had put their Mae West life vests around their waists instead of under their arms.

Ironically, the death toll in Exercise Tiger was more than four times the 179 GIs killed at Utah Beach on D-Day.

Rubin, 64, a garment manufacturer born in the Bronx, N.Y., and now living in nearby Plymouth, was on a landing craft that opened fire on fellow Americans. He said the sight of the sea covered with dead bodies ''as far as you could see'' has haunted him ever since.

''I feel peace of mind at last - that's it,'' said Rubin, who has been coming to Slapton Sands every April 28 to spread flowers on the sea.

Retired U.S. Army Sgt. Theodore Liska, 68, of Chicago was in the advance wave of Exercise Tiger but didn't find out about the casualties until after D- Day.

''I came over just for this, to pay homage to the ones we left behind who actually won the war,'' he said. ''They gave their lives. A person like myself - we just did our part.''

Emett Bailey, 62, of Durham, N.C., said he flew here for the ceremony to dispute unconfirmed reports that hundreds of Americans were buried in mass graves and are still there.

Bailey, part of the graves registration unit that collected the bodies for temporary burial at a U.S. military cemetery in Brookwood, England, said: ''There are no mass graves. It's an insult to the integrity of the Graves Registration Service at that time to say that.''

Nonetheless, local resident Dorothy Seekings insisted at the ceremony that she had seen GIs being buried in a mass grave which is still there, though she has refused to take anyone to see it.

In the secrecy surrounding D-Day, the casualties in Exercise Tiger were never reported. After the war, they were mentioned in books and official histories but most Americans had never heard of ''the night of the bloody tiger'' which resulted in one of the single largest losses of life in the war after Pearl Harbor.

Gen. Sir Peter Whiteley, representing the British government, and Lt. Gen. Ronald L. Watts, commander of the U.S. Army's 7th Corps in Stuttgart, West Germany, both stressed that the sacrifice of the men had helped secure the final Allied victory.

Watts said it was time to ''rededicate ourselves to maintaining that peace for the future.''

''This tragic loss of lives in April 1944 tragically reminds us that freedom isn't free, but requires dedicated men and women who are willing to fight for that freedom,'' he said.