Beach Dorks and Wistful Chicks : FROM ROCKAWAY<i> by Jill Eisenstadt (Knopf: $15.95; 212 pp.) </i>

“From Rockaway,” a first novel by Jill Eisenstadt, is touted, via its press release, as “A stunning group portrait of unshockable youth,” as an East Coast “Less Than Zero.” The book is nothing of the sort; “From Rockaway” is a sweet, wistful coming-of-age saga, a fragmentary view of teen-agers vibrating between high school flings and adult responsibilities.

Rockaway, also dubbed “Rot-away” and “Rockapulco,” is a New York suburb, “just a tiny strip that hangs off Queens as if it isn’t sure whether it wants to break away and become an island or hang on tighter, desperate not to be abandoned.” “From Rockaway” concerns itself with a gaggle of lifeguards, male and female, who live for the beach. These kids are not a wildly political set; one guy, nicknamed Chowder, “hates Reagan for being in Santa Barbara where it’s warm. The guy doesn’t even surf, what a waste.” The lifeguards lead casual, beer-drenched lives, rife with Prom Night antics and make-out sessions, until fate muscles in, in the form of high school graduation; “It’s strange,” says one, “to all of a sudden have to be something.”

The novel covers the year after graduation, in which Timmy and Chowder, the dudes, continue their lifeguarding and daydream of careers as firemen; they wind up enrolling in the Famous Bartenders School. Timmy and Chowder are homeboys, idlers, big-shouldered louts doomed to be outpaced by their live-wire girlfriends, Peg and Alex. “Good old Timmy,” Alex sighs, “exhaustingly loyal to everything.” Peg, “beautiful, aggressive, carefree” strides through the book, drinking the guys under the table; Alex packs off for a New England college, the lone escapee from Rockaway’s lower-middle-class aimlessness and endless gray winters.

Alex is astounded by New Hampshire, where “trees are not puny, diseased things, they’re climbable. Leaves hardly resemble the tannish sawdust balls at home.” Alex makes new chums among the undergraduate trust-fund strata; she attends “Dress to Get Laid” parties and plunges into masochistic trysts, all the while receiving passionate post cards from Timmy. Peg crashes the campus; Alex is grateful for Peg’s rowdy habits, for reminding her that “Rockaway girls don’t need toilet paper.”

Alex returns to Queens for her summer break; the novel climaxes when Timmy is unable to save a child from drowning. Timmy undergoes the Death Keg ceremony, a ritual in which his fellow lifeguards bury Timmy up to his neck in the sand, “a vertical make-believe grave”; a bonfire is lit and a drunken chant welcomes Timmy to “The Murderers Club.” The Death Keg is a nightmarish event, intended to purge Timmy and his co-workers of guilt over the dead child. Afterwards, the lifeguards assemble at 2 a.m. on the Gil Hodges Memorial Marine Park Bridge; they taunt each other to dive into the ocean below, to join “The Brass Balls Bridge Jumpers Association.”

These final scenes are over-heated rite-of-passage stuff, a tad too symbolic; teen-age dares become true tests of courage and an unknown future is represented by the lethal tides of the Atlantic. The earlier sections of “From Rockaway” are unpretentious, honest and affectionate, as Eisenstadt depicts tiny shifts in post-adolescent friendships and love affairs. None of the characters are particularly vivid, and this feels intentional; the author is speaking of regular dorks, beach chicks, personalities in their primordial stages. While this approach provides real tenderness, it can also be hazy; at times the characters become underdefined, mere sketches, rather than full-blooded folks worth reading about.

Eisenstadt shines in the details, in snapshots, in describing a Catholic mother who permits her son to munch Lucky Charms, a breakfast cereal, “because the leprechaun on the label made it vaguely Irish.” Another mom has a husband away on business; in his absence she “falls in love with Magnum P.I. or Kirk from that police show or, when she gets a chance, Bruce Lee.” Eisenstadt is sharp on parental quirks; Alex knows that “It doesn’t take all that much to please her mother: neatness and beige.”

The minutiae of a lifeguard’s amiable days are also well-documented, anchoring the book in fresh experience. The lifeguards inhale pure oxygen from their lifesaving tanks to deflect hangovers; they wrap Alka-Seltzer tablets in bread and feed these nuggets to unwary gulls; “The birds’ insides explode.” The volcanic ceremonies that close the book remind us that lifeguarding entails an ever-present specter of death; these teen-agers, their noses slathered with zinc oxide, are nearly destroyed when a rescue aborts in tragedy.

“From Rockaway” is less a novel than an album, a series of feisty, compassionate literary Polaroids. The book’s range is kept deliberately narrow, limited to a single year in the lives of people who don’t do much. Eisenstadt is a thoughtful writer; she never satirizes or patronizes her small-town crowd. While this is commendable, Eisenstadt is clearly capable of larger work, of a more rigorous assignment. “From Rockaway” is small but endearing, flecked with the moments in life when, as the author observes, “there’s nothing left to feel except young and a little sad.”