When an announcer midway through the show says, "The Love Boat' will continue in a moment," it's more of a threat than a promise. Obviously there's always going to be a certain amount of worthless tripe on television, but shows like "Love Boat" pull the median level of mediocrity down to unfathomable lows. Nothing is worth the boredom of the deep.

ABC's one-hour episodic comedy, premiering as a weekly series at 10 o'clock tonight on Channel 7, offers two or three episodic vignettes per show, each involving one or more guest-star passengers. In spirit at least, this is one cruise ship that never leaves L.A. and never enters the realm of probability.

"Boat" might be interesting as an actor's test, however, since it takes plenty of furious paddling to keep one's head above water when material gets this rock-bottom. On the opener, only Jimmie Walker and Brenda Sykes survive the ultra-small tales about sex on the knee-high seas.

Regulars in the crew look and act as plastic-perky as the counter-keepers you see in fast-food commercials but never see at fast-food restaurants.

Gavin MacLeod, ex-Murray of the "The Mary Tyler Moore Show" appears perpetually ashamed as the captain and he should.

"Love Boat" may have a few inadvertent things to say about the declining status of marriage in the whoopee world. Walker and Sykes play a couple who have lived together for two years and only marry when she tricks him into it. The captain spends the hour dodging a shrew he divorced after 17 miserable marital years. The ship's doctor notes cheerfully and almost with pride that he's been married four times.

And perpetually partying blonde ends her very cruisey cruise by embracing two offspring of her failed marriage, who are waiting for her on shore.

The program also maintains that black people kiss each other longer than white people do, thus perpetually an old racial-sexual stereotype.

Sociological asides notwithstanding, "Love Boat" proves even less funny than its protype, the unlamented comedy anthology "Love American Style."

ABC's least intelligent comedies this season, measwhile, turn out to share a nautical theme: "The San Pedro Beach Bums," "Operation Petticoat" and now "Love Boat." The show we all deserve is one in which the "Petticoat" pink submarine rams the love tub right into the beach bums' houseboat.