Since there hadn't been a civil war on Marlyland's Eastern Shore lately, no one quite knew what weapons would be used if one evolved. Giant drumsticks from those famous Delmarva chickens? Chesapeake Bay crabcakes at 30 paces? Now we know; crosses tennis rackets at 30 miles.

THat is the distance between Salisbury and Ocean City, which are less than neighborly nowadays when someone mentions tennis. Unlikely as it seems in the midst of the worst winter, weather-wise and economically, in years, two rival tournaments are being played in these modest Eastern Shore communities this week.

They are very different in character - Salisbury's a homey amateur event, Ocean City's a big-money proaffair for national television - and the people behind them insist there is no "war." But obviously feelings have been strained.

And when Bill Riordan - long Mr. Tennis in Salisbury but now the prime mover of the Ocean City tournament - is involved, there is bound to be a war of words. He is a natural showman with a gift for flamboyant and dramatic overstatement, and he has said a few unpleasant things about the tournament committee in Salisbury. Oh, what a lovely little war!

Salisbury still proclaims itself "Tennis Town, USA" in bannrs and posters, and thinks of this as "Tennis Week," even though the U.S. Indoor Championships, which were brought from New York by Riordan and played here every year through 1976, have moved on to a richer purse and bigger arena in Memphis.

In place of Jimmy Connors and Illie Nastase, the National Amateur Indoors, involving mostly college and high school players from across the country, have come to this town where 20,000 people and more chickens than anyone can count reside. Salisbury has taken them warmly to its bosom.

Fire events are being played at the Wicomico Youth and Civic Center - men's and women's singles and doubles, and mixed doubles. The participants and assorted coaches and visitors are given hospitilaty at the homes of the townspeople, and all the trappings of tennis week - balls pinging against rackets, popcorn bursting from machines, parties all around town - are again helping brighten a gray, gloomy February.

It's not the glamour event the pro tournament grew to be in 14 years, but as chairman Joe Gilbert said yesterday, "It's a pleasant atmosphere. The community is enjoying it. The kids are great. They appreciate what we're doing for them, and that's nice. There isn't a stinker in the bunch. Nobody on court has given a finger to anybody all week."

Meanwhile, Riordan who mobilized his adopted hometown to support the Indoors and made it "Tennis Town, USA" through his promotional and organizational flair, is not here Salisbury seems somehow dull and empty without him.

His commiteemen are all at their old familiar posts until it is time to go for some tennis week refreshments at old familiar Johnny and Sammy's Restaurant, where the hostess still wears her old familiar tennis week pin, shaped like a racket.

But Riordan is 30 miles east on Rte. 50, in Ocean City, helping put on a $100,000, 16-man event at the Convention center. Nastase vs. Vitas Gerulaitis and Guillermo Vilas vs. Bob Lutz were tonight's attractive semifinal pairings, the winners to meet for $32,000 on CBS-TV Saturday afternoon.

The telecast is central to the rift, because it is what brought about the conflict in dates between tournaments that originally were to be separated by more than a month.

Riordan, who repeatedly pulled rabbits out of his hat to keep the NationalIndoors in Salisbury with a $50,000 purse, did his best to bring the pros back this year. But the price tag simply became too high. No sponsor was forthcoming to make the difference between $100,000 in prize money and what revenues could be generaged at the gate of a building that seats only 3,000.

With Salisbury out of the picture, Riordan went about bringing a pro event to Ocean City, working with former Romanian Davis Cupper Ion Tiriac and his partner in promoting events, Bill Dennis.

The city agreed to underwrite the prize money for a tournament in late March and April, to be televised by either Home Box Office (cable subscription TV) or the Pblic Broadcasting Service0. The object from the city and chamber of commerce's point of view; national exposure to spur tourism, the principal industry in a resort that expands from 3,500 sleepy winter inhabitants to a peak summer population of 200,000.

Fine and dandy. Pro tennis would remain on the Eastern Shore, where it has been so popular. Meanwhile, Joe Gilbert an unassuming 38-year-old college administrator with a striking resemblance to actor Jack Webb, suggested to some members of Riordan's old volunteer committee that it would be nice to have an amateur event in Salisbury.

"As so often happens when a committee likes your suggestion," says Gilbert, who came here five years ago to become assistant to the president of Salisbury State College, "they appointed me chairman."

Gilbert guessed that a little more than $40,000 could be raised in box seat and ticket sales for the National Amateur Indoors at Wicomico Youth & Civic, an estimate that has turned out to be correct. With that, he figures, he could afford to fly in top college teams and put on first-class event for the up-and-comers.

"The people of Salisbury were saddened by the loss of the pro tournament. It was the highlight of the year," says Gilbert. "We thought that a good amateur event would still be a recreational and social outlet for the community; something people could look forward to get involved with, have parties around. An evcuse to get together and keep 'tennis week' alive."

At first, Riordan was helpful and supportive. He gave Gilbert operational checklists, past financial statements, names of contacts, and other helpful advice. He promised his box seat and ticket buyer lists.

The problem arose when Riordan, in his capacity as tennis consultant to CBS, moved the Ocean City tournament up to fill a Feb. 19 TV date that had become vacant.

Ocean City Mayor Harry Kelley was delighted at the prospect of being on a major commerical network. Riordan assumed the Salisbury could be changed, even though Gilbert had said otherwise, and finalized the deal.

Gilbert says that he was locked into his dates because he already had a sanction for a national championship from the U.S. Tennis Association, and the only other week the Civic Center available was a bad one from the standpoint of getting college players. Riordan says that Gilbert was simply being pig-headed and "had some strange emotional attachment to this particular week."

Meetings were held, phone calls exchanged, but neither tournament wanted to budge from its place on the calendar. Accounts of the behind the scenes maneuvering are complicated and tedious, but accusations and counter-charges have flown in both directions.

"I think Bill's ego was wounded," says Gilbert. "He thought the community owed him a point of personal privilege for everything he had done over the years. He was sure if he said, 'change the dates,' Salisbury would. When it didn't, he got very angry."

"Gilbert and his guys kept saying they didn't think an amateur tournament in Salisbury would hurt Ocean City," snaps Riordan. "I kept trying to explain to them that Ocean City could hurt Salisbury, and they'd destroy spectator tennis in Salisbury forever."

Riordan even claims his office files were ransacked after he refused to cooperate with the Salisbury committee if it didn't change dates. "With Watergate in mind," he crows, "I had already move the appropriate files to my home."

Riordan threatened a lawsuit and Gilbert, who says he knows better than to engage in a verbal battle with a master of the art, just smile. "I wouldn't know what to do if I was sued," he said. "I'd have to sell my car, my wife and kids, I guess. I couldn't buy Boy Scout uniforms for the national jamboree this summer."

"Hey, that guy's pretty good copy," retorted Riordan, a note of administration in his voice, as he read what Gilbert had said. "Tell him I'll take the car, but he can keep his wife, the kids and the Boy Scouts."

Actually, both tournaments have done just fine, thank you, considering the odds. In Salisbury, 126 of 132 boxes were sold, 800 to 1,200 people have shown up each night, and the weekend promises nearly full houses. The $42,000 "nut" was covered a week ago, and there will probably be a profit of a few thousand dollars going to the beneficiary, the Salisbury state College Foundation.

Crowds in Ocean City's 2,600-seat facility have climbed from 1,300 on opening night Tuesday to 2,000 Thursday, and tickets are sold out for the city's 7,000 condominium owners and out-of-towners on off-season holiday packages. Major Kelley has been delighted, and will be more so if the ratings from Saturday's telecast are good.

"I thought we could co-exist because we're serving different constituencies," said Gilbert. "I never wished Ocean City or Bill Roirdan ill.

"Apparently they've been successful, and we certainly have been. If you compare this to other amateur events, apples to apples, we have a supper affair here. The players have all told us that. The community has enjoyed it, and proved that it really it "Tennis Town." There aren't too many places where you could draw this many people to see amateurs, and have this kind of support. And none of the spectators feels the least bit cheated.

What about Riordan's ego? Does he feel vilified in the hometown he and chicken king Frank Perdue put on the national map?

"Not at all," he says, "I'm calm and relaxed. The whole thing is therapy for me. I have more important things to worry about. If I'm vilified, it is only by a small group of dissidents.

"And, I should point out, my image in Ocean City is very good. The mayor told me I could have residence if I'm expelled from Salisbury. They even gave me the Mr. Nice Guy Award the other day. Come to think of it," he concluded, "an honour like that could ruin my reputation."