WATERMAN By Doug Hornig Mysterious Press. 348 pp. $16.95

The Chesapeake Bay harbors a load of evil in Doug Hornig's "Waterman." Blackmail, drugs, smuggling, rape and murder line its shore and poison the lives of the good and not-so-good citizens of Dorset County, Va., a backwater throwback to the days when courthouse gangs ruled the South.

Into this den of iniquity straggles a stranger who calls himself Scott Craik, a traveler trying to find himself and lose his past. A former special operative of a never-named top-secret U.S. agency, he's dropped out and gone underground, disillusioned by his and his agency's role in the invasion of Grenada.

Naturally, he's lean, hard and handsome. Of course, he can handle himself and weapons. And he even has a conscience.

He's going to need all that and more, given the nest of vipers he's stumbled into in the claustrophobic little waterside town of Brawlton. There's Judge Forrest Holder, who's masterminding some kind of dark-deeds operation. He also controls the county's seafood enterprises, politics and sheriff's office.

There's the ever-so-slick sheriff in his wood-paneled office, and his two swaggering deputies, a couple of magnum-toting brutes used to getting just about anything they want -- including women. There's a two-bit thug whose knife leaps into his hand at the merest hint of an excuse. There's the "negotiator" from a South American crime family. He's dropped in to persuade the judge that his operation would lend itself very nicely to the family's plans to run drugs. There's Craik's former agency masters, who want him back in the fold -- or neutralized. And for that final element, there's a woman he comes to love.

If ever a town has reached critical mass, it's Brawlton. The explosions of violence are inevitable, savage and powerfully rendered.

Unfortunately, there are some difficulties in getting from explosion A to explosion B. And most of them have to do with Hornig's prose style, which goes pretty much like this:

"He moved in and out among the pines, water oak, and sycamores that grew right down to where the land merged with the water. He played his flashlight over the ground. The splashing ceased. He switched his flashlight off and moved more cautiously. He stopped, listened. There was the sound of tortured breathing. He headed toward it."

Yes, short, declarative sentences can be admirable in their clarity and simplicity. And, yes, they can soothe our slumbering brains of summer like waves upon the sand. But when they march in boring lockstep for more than 300 pages, we ache for the equivalent of the random rogue wave.

In fairness, "Waterman" does mark something of a departure for Hornig, whose previous three novels -- "Foul Shot," "Hardball" and "The Dark Side" -- featured Loren Swift, the only private detective in Charlottesville. Two of those novels were particularly well received: "Foul Shot" received an Edgar Award nomination for best first novel in 1984, and "Hardball" a Shamus Award nomination for best private eye novel in 1985.

But Hornig clearly isn't as comfortable with or skilled in the ways of secret agents, which may explain the disappointingly thin development of Craik's spy craft experience and the murky vagueness of the agency for which he worked.

On the other hand, Hornig has obviously done his homework on the water. He has a sure and solid feel for the hardships watermen face in wringing a living from the Chesapeake. And so when Craik comes to town, he doesn't find the sporting bay, the playground of weekend sailors and bluefish trollers. He finds the working bay, a place of broad waters and narrow options, of hard work and harder drinking, of battered boats and bad bank loans, of broken backs and lost fingers, of diesel fuel that costs too much and shellfish that bring too little.

His (and our) understanding of that life grows as he learns how to run trotlines for crabs and seine for menhaden, when he discovers to his surprise that many watermen, after a lifetime upon the water, can't and don't care to swim. And that appreciation of a special way of life is almost enough to elevate "Waterman" beyond a breezy summer read.

Almost. The reviewer is a senior editor for The Washington Post Magazine.