"IT'S BEEN really good this year," says Bert Shaffner, skipper of Optimist II, as he eases the boat away from the dock at Chesapeake Beach.

"We caught over a thousand fish yesterday." We pass a green buoy on which three young ospreys sit in a large nest of sticks, waiting for lunch, and head 12 miles across the bay to the mouth of the Choptank River in search of sea trout and jumbo spot.

My heart quickens in anticipation. Like the 43 other anglers aboard, my companion and I, armed with nothing more than a carton of bloodworms and rented rods, are determined to bring home our dinner from the bay rather than the Giant.

"In fact," Shaffner continues, "today's only the second bad day I've had out here this year. We didn't get a thing this morning, you know." My heart falls. The old you-shoulda-been-here-yesterday.

"Don't fret about it," calls a man from the shade of the afterdeck, producing a cold beer from his cooler and a deck of cards from his pocket to while away our hour-long crossing. "Sometimes you get nothing all morning, then, come the afternoon, you clean house."

He smacks a fist into his palm for emphasis. "We'll get some today. I can feel it."

The Chesapeake Bay abounds with both fish and charter boats to chase them, from luxurious air-conditioned pleasure craft for corporate outings to small fishing boats that, starting at about $200, will take a party of up to six people out for a day of trolling for bluefish -- captain, mate, gas and bait included.

For those on tighter budgets, there are several headboats (so named because passengers pay "by the head") plying the bay out of the Western Shore at Chesapeake Beach and near Point Lookout.

The fishing season on the nearby bay generally runs from May into October, August being prime time. Shaffner likes to head across the bay to oyster beds at the mouth of the Choptank on the Eastern Shore, because sea trout and spot congregate there, feeding on worms that attach themselves to the oyster shells.

Both fish are great eating. Jumbo spot, the ones headboats go after, average seven ounces to 10 ounces. Sea trout are considerably larger. And don't worry about cleaning your catch. Most anywhere there are charter fishing boats, there are people at dockside who clean fish for a nominal sum.

Just before we arrive at the Choptank, Brian, the mate on the boat, collects three dollars, hands us our rods and explains how to work them. Each rod is rigged with a four-ounce sinker and two hooks on heavy monofilament line. The hooks are baited with cut-up bloodworms (also available dockside, natch) and thrown overboard. The trick is to allow enough line out so that your bait is resting on the bottom, but not so much that slack prevents feeling a nibble.

Captain Shaffner locates a school of spot on his fishfinder sonar, and soon we are hauling some aboard. Few sensations are as gratifying as dropping a line overboard and feeling something tugging on it. Each strike prompts whoops and shouts of "yeah!" from even the more experienced anglers on the boat. Spot are not big fish, but they are lively. They move in circling schools, and the action is on-again, off-again for the next three hours as we play hide-and-seek with the spot. A few small sea trout are brought aboard, as are more than a few toadfish -- ugly, spiny guys with jaws strong enough to crush oysters. These are unceremoniously dumped overboard.

Finally, everyone having landed enough fish for several dinners each, we head into the setting sun. The rhythmic rocking of the boat, the sea air and sunburn lull half of the assembled company near to sleep, stretched out on the roof of the cabin or on the deck. The ospreys, also sated, make scarcely a squawk as we pass.

Yawning on the drive home, with cleaned fish on ice and fresh sweet corn and tomatoes from a roadside stand in a paper sack, I keep myself awake by computing the price per pound of our fish. Seven pounds of spotfor a total of $58 (counting the fare, rod rental, bait, gasoline and having the fish cleaned) works out to just over $8 per pound, probably three times their cost at the supermarket. It's not the cheapest way to get a fresh fish dinner. But it may be the most fun. HEADING OUT

A sampling of headboats operating off the Western Shore is listed below. Fishing licenses are not required. Suntan lotion, a hat, food, beverages and a plastic cooler with ice are recommended for a day on the water.

FISH N PARTIES INC. Ridge, Maryland. 301/872-5815.

Runs headboats out of St. Jeromes Creek (about seven miles north of Point Lookout) seven days a week. 8 to noon and 1 to 5. Cost is $14 per person, bait included. Rod rental is $1.50. These boats generally go after bluefish. Also runs 8:15-to-3:15 bluefishing trips seven days a week; cost is $22 per person, some bait included; rod rental $3. Also runs bottom-fishing trips for sea trout and spot on Wednesday and Thursday, 8:15 to 3:15. Cost is $22 per person, bait included. Rod rental is $3. Also runs charters for up to 20 persons, starting at $350.

SCHEIBLE'S FISHING CENTER Ridge, Maryland. 301/872-5185.

Runs headboats out of Ridge, near Point Lookout, seven days a week. 8 to 4. Also Saturdays 6 p.m. to 2 a.m. Usually chums for bluefish. Cost is $25 per person, bait included. Rod rental is $3. Also runs charter boats for up to six persons, starting at $290.

ROD 'N REEL DOCK Chesapeake Beach, Maryland. 301/855-8351.

Runs headboats seven days a week: 8 to 4 weekdays; two trips per day on weekends, 6 to noon and 1 to 7. Cost is $20 per person, bait not included. Rod rental is $3. Also runs charter boats starting at $200 for up to six persons.