Julio Cortazar's vivid satire on chance; The Winners, by Julio Cortazar. Translated by Elaine Kerrigan. New York: Pantheon Books. 374 pp. $8.95. Paperback.

''The Winners'' (recently released in paperback) was the first novel by Julio Cortazar to be published in the United States. Readers of the author's daring fictional experiments such as the novel ''Hopscotch'' and the filmscript ''Blow-Up'' will find ''The Winners'' surprisingly conventional in structure.

But the form will prove deceptive; upon closer reading, ''The Winners'' is a masterly novel of ideas, sparkling with vivid satire on chance and the mortal games of human imposture.

A group of lottery-prize winners is on a celebratory cruise that has been planned by the state. The passengers are an exuberant, diverse mixture, aglow in the excitement of their newly acquired fortunes.

But just before departure, the ship is changed from a luxury cruiser to the freighter Malcolm. No sooner has the ship put out to sea than something seems wrong. No one will reveal the ship's destination; the stern is declared off limits. A sense of dark menace and gloom pervades the winners.

Suspicion that the ship is contaminated with a plague induces divisions among the passengers. The ''war'' party wants to challenge the crew and the quarantine; the ''peace'' party does not.

Among the major characters is Persio, a proofreader and dreamer. His passionate monologues often serve as narrative commentary on the events. Persio also becomes the vehicle for some of the most lyrical and powerful prose evocations that Cortazar has ever written.

Finally a confrontation ensues between the passengers and crew. Characterizations deepen into extravagant portraits of humanity; isolated and fearful, each character seems to be acting haphazardly to achieve singular goals.

Plans are made to break through to the stern of the Malcolm in defiance of the crew. Who will discover the secret? The stern becomes a forbidden challenge, a symbol of repressive authority; one by one the characters find in it a vision of their past and a clue to their destination. In relationships born of desperation, the travelers achieve a special kind of communion.

''The Winners'' is a powerful allegory, both comic and lyrical in the tradition of Latin American social realism. Characterizations are so numerous they are sometimes bewildering, but then character is less important here than fate.

As Cortazar once explained in an interview, ''The Winners'' is not (despite what it achieves) meant to be an allegory, but ''an exercise in style.'' It is also a remarkable novel.