Dry land was not the only place where things were booming this Independence Day weekend.

The "boom-booms" in the Chesapeake Bay are thick enough off Sharp's Island Lighthouse that they appear on a depth finder like an acre-wide stack of cordwood.

"Thousands," said Capt. Dick Houghland. "They're stacked up six-feet deep. There's a flat smoking jag of them in there."

Boom-booms is what those who fish the Bay have come to call black drum, probably the biggest fish that swim into the Chesapeake. The nickname comes from a noise the giant bottom-feeders make, apparently by striking floating bone in their heads.

In years past, black drum, which grow in sizes above 100 pounds, have rarely made it into the middle stretches of the Bay. But three years ago, for reasons unknown, they appeared in huge numbers on fishermen's depth recorders at the Stone Rock, a shallow oyster bar marked by Sharp's Island Lighthouse at the mouth of the Choptank River.

On June 12, 1978, they made their first appearance and hung around in numbers for almost a month, to the delight of Bay fishermen accustomed to catching much smaller species.

In 1979, they appeared on the same date, which left a few people scratching their heads.

Yet, this year, the black drum threatened not to come at all. It wasn't until the last weekend in June that depth finders lit up with the tell-tale six-foot-wide band and fishermen hurriedly rigged soft crab baits to drift through the schools.

It's been wild ever since.

Last Monday, when the wind blew fiercely and most boats stayed in port, Houghland took an afternoon party of charter fishermen to the Stone Rock and in four or five hours managed to hook and boat 20 black drum, averaging about 40 pounds.

That's 800 pounds of fish for an afternoon. The fishermen kept a few but put most of the big boom-booms back.

Tuesday, Houghland found them again, but only at the crack of dawn. Other boats were present from Tilghman Island, Deale, Annapolis, North Beach and Chesapeake Beach.

"We made one drift through and hooked those five," Houghland said. "Then the boat traffic spooked them and we never saw them again all day. Who knows where they go?"

Wednesday Houghland was at the dock at 5:30 a.m. to try again with an anxious party of black drum novices. And a new mate.Me.

This I had to see.

We set off southeast from Chesapeake Beach into a sun rising red and a quartering 15-knot breeze from the south.

On the east side of the main ship channel, the water depth began easing and finally shallowed to 17 feet at the Stone Rock. Black drum feed there, crushing small crustaceans with slab-like teeth in the backs of their throats.

But it's a big place and it all looks the same. You have to find the school.

Houghland stared at the flashing red of the depth meter and began slicing across the miles-wide bar, where skipjacks dredge oysters in the water.

Three or four other boats joined the search.

First it was quiet, then suddenly there was chaos. "There they are," Houghland said and jumped up to throw out a marker buoy. The other skippers saw that and converged rapidly.

I hurried to the bait box and rigged chunks of soft crab ($10 a dozen) on 5/0-size hooks with two-ounce sinkers above them.

Houghland pulled the boat upwind of the marker buoy. The five fishermen abroad dunked the crab baits to the bottom and we drifted into the huge pile of huge fish. They were so thick you could feel them bumping the lines.

Russell Toole felt a surge on his line and jerked the rod back. One fish on. Fish grabbed two other baits. Tow rods aboard the neighboring Miss Dolly bent double.

Chaos, to the tune of grunts and groans.

And then nothing. All three lines aboard our boat went slack, one by one. One fish broke the 30-pound monofilament, two simply released the hooks.

Then they were gone. The school had disappeared.

As morning wore on, the other boats drifted off to go bluefishing, discouraged by the fruitless search. At 10 a.m. only we were left.

"Want to go for blues?" Houghland asked Bob Daniel, who organized the charter.

"Stick with the drum," said Daniel. "I can catch bluefish anytime I want."

Stick they did, in an increasingly hopeless plight, until 11:15, with only 45 minutes of the morning trip remaining.

"Good gracious," said Houghland. And it started all over again.

This time the fishermen, not the drum, were lucky. Toole latched onto the one that had gotten away or another one like it. Jack Donahue felt his line surge with a great weight. Daniel got one. Then a dinosaur hit Mark Scheibert's line.

They did the merry dance of crowded fishermen keeping lines clear on a small boat. When it was over shortly after noon five drum filled the fish box. The biggest was Scheibert's at 48 pounds.

They were a happy bunch.

That afternoon, with a new party of five Pennsylvania school teachers aboard, Houghland located the school one more time and the Pennsylvanians had their turn. Steve Steinke, slat him and wiry, got all he could handle when a 60-pounder swallowed his crab bait.

"Jeez," he said when it finally was over. "I don't want any more of that."

About that time, Houghland found the school again. Steinke grabbed his rod hurriedly. "Hey," he said, "gimme some bait. Quick."