If Benny Holland and Clyde Fitzgerald hadn't become officials at the International Longshoremen's Assoc-iation, they'd have made first-rate salesman. They're articulate, they're assertive, they know their product and they're good listeners.

Those qualities will be severely tested in the coming months when Holland and Fitzgerald, the president and secretary-treasurer of the ILA's South Atlantic and Gulf districts, respectively, try to persuade shippers to give the union a second chance.

It'll be a difficult sell. Many shippers are contemptuous of the ILA and have no sympathy for the problems the union has faced during recent years. Container lines that have signed the union's Maine-to-Texas master contract are still required to use ILA labot, but since the mid-1980s the ILA has lost much of its bulk and breakbulk work in Gulf ports to non-union competitors that offer lower costs and more flexibility.

The ILA was slow to react to the non-ILA challenge but eventually agreed to concessions such as flexible starting times, a lower wage scale for bulk and breakbulk cargo, a reduced entry-level wage and an ''ILA Lite'' arrangement in New Orleans and Mobile that provided lower wages and benefits for workers handling cargoes targeted by non-ILA firms.

Though the non-ILA share of the market appears to have stabilized, the union generally has been unsuccessful in regaining the jobs it has lost. The effect of the job losses on the ILA and its members has been devastating. The membership of New Orleans' largest ILA local, which once numbered several thousand, has shrunk to 400. Many longshoremen for whom the ILA had been a ticket into the middle class now are struggling with low-paying service jobs.

The loss of business and jobs has brought union and management closer together. They're cooperating on programs such as training, drug testing, security identification, and work-rule changes such as a current proposal to allow longshoremen in some ports to work regularly for the same stevedore instead of reporting to a different terminal each day.

Now the ILA is planning to take its message to shippers, including those that have written off the union. The ILA's South Atlantic and Gulf district has hired a consultant, Leo A. Boles III of Target Shipping Co. in Mount Pleasant, S.C., to identify major shippers in each port in the region.

''We intend to go directly to the shippers, to talk to them, to learn what their concerns are and to sell them on our product,'' Fitzgerald said. ''To do that, we have to have a product to sell. We believe we do have a good product. We believe we can get back in the game.''Jim Morrison, vice president of the West Gulf Maritime Association, which represents waterfront management in Texas ports and Lake Charles, La., agrees that shippers have a stake in maintaining a stable longshore work force that is trained, drug-free and large enough to handle surges in demand.

''In their drive for the bottom line, they may be hurting themselves,'' Morrison warned. ''Breakbulk is so cyclical. What will happen when we get another surge in steel? Will the shippers be able to get their cargo handled promptly and without damage?''Holland, who succeeded the late Buddy Raspberry as district president in 1990, said he was determined from the time he took office to work with management to prevent further job losses. He set up a committee of 18 ILA officials and 18 management representatives that meets regularly to discuss problems and find solutions.

Sometimes the ILA officials' sales work has to be directed at members as well as to outsiders. Not all of the union rank-and-file has accepted the need for change. Backbenchers within some of the local unions remain poised to exploit concessions by using them as ammunition in intra-union politics.

But Holland and his aides seem to be making headway. For example, some senior ILA members in Holland's hometown of Galveston objected to a plan that would allow skilled workers such as winch and forklift drivers to work exclusively on palletized bananas.

Ted O'Rourke, financial secretary of Local 20 in Galveston, says he went to see Holland to try to convince him to drop the plan. After being ''cussed out for 30 minutes,'' O'Rourke changed his mind. He now credits the program with improving productivity and generating additional work for his members.

O'Rourke supports the effort to reach out to shippers. Galveston still handles breakbulk cotton, and O'Rourke says the ILA is determined to maintain good relations with cotton shippers in Memphis.

''I'll put on an Elvis costume if it'll get work for our members,'' he said. ''We're serious about this.''