The new executive director of the West Coast's busiest port approaches his job cautiously.

The port and his colleagues who know him count on his management and negotiating skills to overcome his lack of maritime industry experience.Because Joseph F. Prevratil comes to the Port of Long Beach with no previous maritime industry experience, he says it is premature to discuss priorities or changes he might make. He will assume his new post in late June after he steps down as president of Wrather Port Properties, which operates the Queen Mary and Spruce Goose tourist attractions in Long Beach.

Today is the announcement date, he told reporters at a press conference last week. The next two months will be a time to assimilate knowledge of the industry, he added.

Well aware of the skepticism with which the traditional, close-knit maritime industry views outsiders, Mr. Prevratil attempted immediately to calm the fears of those who feel he may not be an ally of the maritime community.

During a career that has spanned some 25 years, Mr. Prevratil has held executive positions in industries as diverse as entertainment, hotels and computers. I feel I was an effective spokesman for those industries. In time, I will be an effective spokesman for the maritime industry, too, he said.

He will assume the leadership role at a crossroads in the port's history.

Long Beach has been the cargo volume leader on the West Coast since 1981. The port has almost no land left for expansion, however, and the neighboring Port of Los Angeles may soon become the busiest port on the coast.

The new executive director therefore faces the task of expanding port facilities through land acquisition and landfill projects in San Pedro Bay. In environment-conscious Southern California, this is a difficult task.

Property development may not even be the most important issue facing Mr. Prevratil, according to Jay Winter, executive secretary of the Los Angeles Steamship Association, which represents ocean carriers calling at the ports of Long Beach and Los Angeles on legislative and regulatory matters.

We can build the best port facility in the world, but if we don't have a good transportation infrastructure behind it, it will not work, Mr. Winter said.

Infrastructure issues have already surfaced in Southern California. Two terminal operators in Long Beach have applied for permission to construct dockside railyards for double-stack trains, and terminal operators in Los Angeles are known to be considering their own railyards.

Also, a regional government organization is encouraging both ports to build a consolidated rail corridor from the harbor area to remove trains from residential neighborhoods.

Add to the rail uncertainties proposals by state and regional groups to restrict truck traffic on Southern California's congested freeways and the extent of infrastructure issues is magnified.

Erik Stromberg, president of the American Association of Port Authorities, said public attention today is focused on port authorities whether their cargo flows are increasing or decreasing.

Growing ports, like those in Southern California, draw attention by contributing to pollution and traffic congestion in the community, while ports with static or declining cargo are questioned for their economic impact on their region.

Many of our port managers would love to have the problems Long Beach has vis-a-vis its cargo, Mr. Stromberg said.

Growing ports also attract attention because of their profit potential. The Port of Long Beach last year reported net income of more than $44 million, and the maritime industry is concerned that the city will attempt to divert some of its revenues to the general fund.

Mr. Prevratil responded to this concern by noting that certain safeguards, specifically those contained in the California Coastal Act, are designed to restrict the use of port revenue to the promotion of commerce. There is no question that we must keep these funds for the port, he said.

The effectiveness with which Mr. Prevratil deals with infrastructure, port development and revenue issues will no doubt influence how quickly he is accepted by the local maritime community. He is the first port director in almost 50 years in Long Beach who has not worked his way up to that position

from inside the port.

At the Port of Los Angeles, Ezunial Burts had a similar experience. When he was named executive director in 1984, he had no direct maritime experience and went through probation in the eyes of the shipping community.

It is difficult to win trust in the maritime community. This is a close- knit and relatively small community. There will be a need for trust- building (for Mr. Prevratil), Mr. Burts said.

He added, however, that it won't take long for someone of Mr. Prevratil's abilities to learn the nuances of the maritime industry. More important, he said, is the role of the port director as manager.

The basic issues of any large business organization are the management of human resources, the management of fiscal resources, setting a vision and a plan, and providing motivation to the staff. Joe has experience in these areas, he said.

Mr. Burts' successful track record in Los Angeles has been cited by the Long Beach harbor commissioners in support of their decision to break tradition and look outside the port for an executive director. Their stated philosophy is that management skills are the basic requirement, and knowledge of the industry can be learned on the job.

Mr. Stromberg of the American Association of Port Authorities hesitates to support such a blanket statement. The port industry faces its own complex problems, such as infrastructure development, shipping trends and macro- economic trade issues. Experience is the most valuable teacher in those areas, he said.

But Mr. Stromberg conceded that the port industry is probably vulnerable to the charge that it has not applied recognized management principles. The AAPA in recent years has addressed this problem through management training seminars for its members.

A trend developing among the most successful ports today, Mr. Stromberg said, is for executive directors to spend the majority of their time marketing and selling their port. Of all the responsibilities of the port manager, marketing is the most crucial, he said.

Mr. Prevratil replaces James H. McJunkin, who established a powerful reputation for his marketing skills, especially in overseas markets, during his 10-year tenure.

Thomas N. Teofilo, who served under Mr. McJunkin as director of trade development before becoming senior vice president of Korea Shipping Corp., feels Mr. Prevratil's biggest challenge may be in establishing his reputation with steamship clients headquartered overseas.