ANNAPOLIS, MAY 29 -- The world has always looked different from inside "the Yard," the sprawling 338-acre campus of the U.S. Naval Academy. In the late 1960s, when many of their contemporaries were protesting the Vietnam War, midshipmen eagerly defended their country's battle.

So it is now as the military college faces what may be its most serious crisis of confidence in 25 years.

On Wednesday, as Vice President Quayle travels to Annapolis to address 1,378 graduating midshipmen, no fewer than five military and congressional investigations are underway into allegations of sexual harassment, unfair or unusually rough treatment and academic improprieties here.

The scrutiny, more intense than at any time since the academy was rocked by numerous hazing complaints in the mid-1960s, has shed a harsh light on the usually mysterious and tradition-bound process by which the academy transforms teenagers into junior naval officers, an education that costs taxpayers $150,000 per graduate.

Today the academy's superintendent, Rear Adm. Virgil L. Hill, announced steps, ranging from creation of an independent ombudsman who will field complaints about treatment of freshmen, or plebes, to an order stating that upperclassmen can be expelled for violating regulations against physical contact with plebes.

Hill reaffirmed a ban on horseplay with involuntary participants.

According to Lt. Cmdr. Mark Van Dyke, an academy spokesman, physical contact with a plebe is now grounds for dismissal after a first offense. However, lesser punishment will remain an option.

While sources say the investigations have uncovered troubling examples of how the system has gone awry, many current and former midshipmen defend the institution, saying its culture cannot be judged by civilian standards.

"We hear about these incidents, and some of it is disgraceful," Midshipman 1st Class Allen Zigler, 22, told 30 members of the National Organization for Women picketing outside the academy gates Monday night.

"But not a lot of people realize what goes into it and are taking it out of context."

At the core of the inquiries is the longstanding question about whether what the academy regards as tough but purposeful "indoctrination" designed to weed out "bad apples" actually opens the door to hazing, which is officially banned. Also at issue is whether what the public perceives as harassment is no more than horseplay that builds camaraderie.

The superintendent's actions today and the investigations were prompted, in part, by a female midshipman's recent disclosure that she was resigning because of the way the academy handled an incident in which she was handcuffed to a urinal and photographed by some of her male classmates.

The midshipman, Gwen Dreyer, has said the academy's response reflected the attitude that women do not belong at the academy.

In recent weeks, several other former midshipmen have contacted their members of Congress and newspapers to tell similar tales and say they were mistreated, subject to unequal justice or forced out of the academy.

According to a congressional source, special attention is being focused on the treatment of women and minorities, who resign and are dismissed in disproportionate numbers.

Among cases being investigated:

The complaint from Paul Trevino, 20, from Springfield, that he was forced to resign after lying about whether he had exercised on a particular day.

Trevino maintains that the lie, committed while he was being intensely questioned by upperclassmen, was simply a misstatement that he immediately corrected.

He said that midshipmen charged with more serious offenses -- stealing and drunken driving -- have been allowed to remain at the academy.

Trevino has also said that he was forcibly bound, gagged and taped to a chair in the days before Army-Navy week in 1988 and that the academy failed to take any action.

A charge from Victor Vaca, a midshipman from Florida who resigned two weeks ago, that he was required to ask permission to use the lavatory and forced to eat and drink until he vomited.

A midshipman's allegation that she was brought up on a conduct charge when she cut short a required physical exercise to change clothes soiled by her menstruation.

The highly publicized incident this spring in which the chairman of the electrical engineering department was removed from his post after he refused to change grades in a required course.

Investigators are also interested in an event this month in which an engineering exam was given despite indications that copies might have been stolen.

Several common threads appear to be emerging in these cases.

Investigators are particularly concerned, for instance, that second-class midshipmen, or juniors, may have too much authority for training and disciplining underclassmen and that unpopular midshipmen are treated more harshly.

"It's not for midshipmen to decide whether someone belongs at the academy. The people of this nation, through the recommendations of congressional representatives, already decide that," said an Annapolis minister who counsels midshipmen.

But several current and former midshipmen contend that outsiders' intrusions into academy affairs have already tied the hands of the upperclassmen too much.

For example, midshipmen are limited in the number of pushups they can require a plebe to do and how much time they can order a plebe to stand at stiff attention.

"You do not want a system that does not judge people," said former Navy secretary James Webb, a member of the academy's Class of 1968.

"A member of Congress judging a computer sheet with College Board scores does not have the wherewithal to determine who can withstand stress and lead," he said.

In interviews, several midshipmen said that although what happened to Dreyer was unusual because the men who handcuffed her were of a higher rank, it was not extremely different from common occurrences.

For example, they said that upperclassmen are often tied to chairs and put outside or have their heads put in toilets as retaliation by plebes they command.

They also said they doubt Dreyer was targeted because she is a woman, but instead think the episode, while wrong, grew out of Dreyer's involvement in a spirited snowball fight.

"You have 4,000 young men and women between the ages of 18 and 25 who are locked up in the same building five nights a week and you have to have some sort of outlet," said Ensign Kevin Bostick, a 1989 academy graduate now stationed on a cruiser in San Diego.

Horseplay is "a big safety valve, and if someone decided this was weird and we shouldn't be doing it, I think there would be a lot more problems," he said.

The academy's defenders conceded, however, that parts of plebe indoctrination -- such as "come arounds" and "chow calls" in which freshmen are required to memorize bits of naval history or that day's menus -- are not necessarily administered equally.

Some companies have reputations for having a larger number of upperclassmen who ride plebes particularly hard.

At the same time, the defenders said, the plebes who come in for particularly rough treatment usually deserve and benefit from it or leave.

Midshipman 2d Class Stacia Johnson said that she was a "problem case" as a plebe.

As a result, she said, "You get yelled at more, but it's just because they want to put more pressure on you to see if you can take it.

"I was asked a lot of times if I was being treated unfairly or being harassed beyond what I should receive. And my answer was 'no,' " she added.

"A lot of the things I had to do when I was a plebe I thought were ridiculous," said Midshipman 2d Class Meg Mullens.

"In retrospect, I can see what it has done to make me a better person and mishipman. It's something I feel proud of for having done," Mullens said.