A cruise ship glows in the harbor and calypso singers serenade passengers in the open-air restaurant of the Ramada Renaissance, but tourists are less numerous than Grenadians had hoped.

The 186-room hotel was refurbished at a cost of $16 million after the U.S. Army moved out in 1985, but industrial investment is far short of expectations.Five years after the U.S.-led invasion stamped out a brutal Marxist regime, monuments and wall graffiti are the only direct reminders of the fighting.

This 133-square-mile Caribbean island of nutmeg plantations, picture-postcard beaches and 94,100 souls oozes tropical serenity, but political and business leaders acknowledge the world is not convinced Grenada's troubles are over.

They had expected a post-invasion bonanza of tourists and foreign investors. It has not materialized, and frustration is setting in.

"When the invasion happened, a lot of people said, `Well, Grenada is now well-known,' " said Andre Cherman, immediate past president of the Grenada Hotel Association. "But the way it's known is for turmoil and unrest."

The United States, with support from seven Caribbean nations, sent 6,000 Marines and paratroopers on Oct. 25, 1983, to oust a military junta that seized power in a murderous coup six days earlier.

Soldiers killed leftist Prime Minister Maurice Bishop and 10 others, and as many as 100 bystanders were said to have died in other outbreaks of shooting.

Reagan administration officials already had been alarmed by Bishop's close ties with the Soviet Union and Cuba. They said the invasion was necessary to protect Americans, including several hundred students at a medical school, and keep Grenada from being used as staging area for communist agression.

Fourteen people were convicted of Bishop's murder in December 1986 and condemned to hang, including former Deputy Premier Bernard Coard and his wife, Phyllis. Three others were convicted of manslaughter and given to long prison terms.

All 17 are appealing, and the matter drags on.

The invasion was criticized abroad as an infringement of Grenada's sovereignty, but Grenadians appear nearly unanimous in support of what they call a "rescue mission" to save the island from anarchy. Oct. 25 now is a national holiday called Thanksgiving Day.

"From my perspective, I know it was most desirable, welcome and acceptable for the simple reason I happen to know what we were going through," Prime Minister Herbert Blaize said in an interview.

His governing New National Party has been plagued by internal bickering, but Grenadian and U.S. officials say the former British colony is irreversibly committed to democracy. Bishop's party got only 5 percent of the vote in the 1984 election.

"I see no stomach among Grenadians for further Marxist-Leninist experiments," said Ford Cooper, U.S. charge d'affaires.

The Grenadian economy, boosted by U.S. aid, grew by 6 percent in 1987 and the current annual inflation rate, although up sharply from negligible previous levels, is a manageable 4 percent.

A surge since 1983 in world prices of nutmeg, bananas and cocoa, Grenada's three main export crops, were an important factor in the expansion, but prices have declined this year.

Prospects for long-term development are uncertain.

Washington, facing colossal budget deficits, has reduced aid to $10.7 million from $51.9 million as recently as 1985. The unemployment rate is 20 percent, and foreign debt is expected to reach a record $71.3 million by year's end.

Since the invasion, the United States has poured in $110 million to make Grenada a haven for U.S. and foreign investment. More millions came from international development banks and friendly governments, notably Britain, Canada and Venezuela.

A $19 million U.S. grant financed completion of the international airport at Point Salines, which had been started by Cuban workers. At the time of the invasion, President Reagan said Cuba and the Soviet Union were building it to accommodate military jets.

Some say expectations of instant prosperity were wildly unrealistic, particularly in light of U.S. budget deficits.

"A lot of Grenadians had the idea they had just been adopted by a rich godfather," said Leslie Pierre, editor of the independent weekly Grenadian Voice. "After grumbling, as some did for a matter of six months, they began to understand that what they expected would not happen."