The Navy admiral who is President Carter's choice to head the General Services Administration hold Thursday prayer breakfasts at his present command. He sings in a church choir along with his wife. And he banned hard liquor at lunchtime at his previous command.

If confirmed by the Senate, Rear Adm. Rowland G. Freeman III, whose selection by Carter was announced a week ago, says he would hold weekly prayer breakfasts at GSA, if the employes are "willing."

If prayer does not help the scandalridden government agency, those who have worked with the 57-year-old admiral say his tough approach will.

"When I have a job to do, I'm going to do it." Freeman said during a 2 1/2 hour interview. In an allusion to the GSA scandal, which has resulted in 45 indictments leading to 39 convictions or guilty pleas so far, Freeman said, "We've got a great country, and if we don't work hard at ir, we're going to lose it."

Freeman said he does not want to prejudge issues at the troubled agency. He said he has long been aware that he could buy some items at local drug stores for less than what GSA pays for them.

"That worries me," said the admiral, flanked by models for submarines and airplanes from his 37-year career as a naval aviator and procurement expert.

In that career, Freeman, who likes to stand during meetings, has made a number of enemies, who are offended by what they consider to be a heavy-handed management style. But even his detractors say he is a strong-willed, hardworking administrator who is impeccably honest, goes by the book, and will not tolerate concealment of embarrassing problems.

"He's intellectually honest and mentally tough," Gordon W. Rule, who worked for Freeman for five years, said. 'I can't think of a better man for that job," said Rule, whose credentials as a cost-cutter are well-respected.

When Freeman commanded a naval weapons base in California, he earned the emnity of scientists he was trying to bring under Navy control. There were some who called him a Captain Queeg, the dictatorial officer from the novel and movie, "The Caine Mutiny."

"His attidue was, "I'm the boss, I'll decide," said Dr. Hugh W Hunter, who was research director of the Naval Weapons Center at China Lake, Calif., which Freeman headed from 1974 to 1977. "He was a vigorous, intelligent individual who failed completely to further the organization's strengths."

Freeman laughed when told he had been likened to Captain Queeg. He attributed many of the complaints to a "heavy resistance to change."

"Productivity for China Lake had been going down for years," he said. "I wanted the facility to be able to assess new technology and make the Navy a smart buyer," He added, "Lots of people would say, I want to work on this, not, 'What does the Navy need?"

A graduate of Harvard Business School, Freeman currently heads the Defense Systems Management College at Fr. Belvoir, Va., which trains procurement officers.

Until 1974, when he became commander of the China Lake weapons center, Freeman was deputy chief of Naval procurement and production In that job, according to Rule, Freeman was a strong believer inobtaining competitive bids and saving taxpayers' money.

Rule, who has retires, gained notoriety when he suggested in a 1972 Senate hearing that former President Eisenhower, a foe of the "military-industrial complex," must have been "twitching in his grave" because Roy L. Ash, the head of Litton Industries Inc., had been named to head the Office of Management and Budget.

Rule, who almost was fired by the Navy for making the remark, said recently. "The Navy will never say what a ship really cost. They think Congress will scrub it . . . Some people in the Navy know what is right, but they're not allowed to do it. Doc (Freeman's nickname) knew what is right."

It was at his China Lake command, where Freeman gained the dislike of many of his subordinates, mostly scientists and engineers. The desolate base, 150 miles northeast of Los Angeles, is names for a dry lake bed on which it is built.

Over the years, China Lake, with aveloped such key weapons systems as the Sidewinder, an air-to-air missle, the Walleye, a TV-guided bomb, and the Shrike, a missile that destroys radar.

Within the Navy hierarchy, the civillian-dominated base had developed a reputation of being immune to direction from Washington and out-of-touch with the Navy's needs. Freeman's orders were to change that.

In many ways, the ensuing struggle was a classic confrontation between scientists, who deal in ideas, and the military, which deals in hardware.

"He destroyed the place," said a scientist who asked not to be identified because he still works for the government. "He had the feeling he was God, and everyone else was his subject."

Taking over, Freeman announced that the base's charter, which gave joint control to a military and civilian commander, had been rescinded.

"People started putting their tools away at 4:30 p.m., and lunches got longer," Hunter, the research director, said. "Previously, people kept working up to u5 hours a day."

"He was more sensitive to criticism than anyone I've met in more than 20 years in the Navy," an officer who worked with Freeman said.

"Reasonably outspoken people would have a management meeting, and 30 people would shake their heads when asked if they had anyting to bring up," the head of an engineering department said. People feared Freeman would become interested in their area and take over, he said.

"He got a few facts from one course, indicating something might be wrong, and he would reach a decision. He was very impetuous," Hunter said.

Like other critics, Hunter said these qualities could help Freeman at GSA which lacks the track record of a China Lake base. "In swinging the axat GSA, that (Freeman's decisiveness) might be good," Hunter said.

In the interview, Freeman said, "I was interested in installing management practises at China Lake. There was no planning. The attitude was, 'Send money, and we'll let you know when we have a product for you.' I'm a taxpayer, too, and I think that's a little too cavalier,"

He said some of his actions could have been misunderstood and contributed to resentment against him.

One was his instruction to move civilians out of housing on the base and into their own homes in the adjacent town of Ridgecrest. Another was the rearrangement of the street where he lived to make it a dead end. He also cut down trees on the desert-like base, planned to close the base library, and abolished the Community Council, which represented the base's residents.

Freeman said it had become Navy policy to move civilians off military installations, ince housing was costly. The rearrangement of hist street had been recommended by security personnel to make it more difficult for vandals to approach his house, he said. He only cut down diseased trees, he said, and the library's books would have been contributed to the local public library.

"The Community Council was becoming less functional," Freeman said. "It was lobbying in directions contrary to base policy."

Aides said Freeman was open to criticism in private. "I criticized his style," an aide said. "When I saw him in his office, he would admit he came on too strong."

Freeman pushed his financial officers to find ways to fund certain projects, but he was told naval accounting did not permit such flexibility. "He would go along," an accountant said.

If anything, some aides said, Freeman overreacted to questionable practices. When suspicions of kickbacks at the Officers' Club arose, he assigned an auditor full-time to investigate its finances. Controls over purchasing were tightened as a result.

When some of the scientists at the China Lake base tried to get him removed, Freeman recalled, "I said to them, "Why don't you have the guts to complain to me first?"

Musing on his days at China Lake, where he enjoyed camping in the mountains on weekends with his wife, Dorothy, Freeman said, "What made the place great was the little people- the blue-collar workers, the hard hats, the technicians - not the scientists. They (the little people) put things into hardware. They'll snap to, like nothing." CAPTION: Picture, Rear Adm. Rowland G. Freeman III, president's GSA choice. By John McDonnell-The Washington Post