"Take the wheel," I said.

I saw her thoughts gathering in her face.

"We didn't refill the air tanks last time," she said.

"There's still some in there. It's not more than twenty-five feet here, anyway. If they haven't settled into the silt, I can get the doors open."

"Dave, it's deeper than twenty-five feet. You know it is. There's a trench right through the Pass."

I got the two air tanks out of the gear box and looked at the gauges. They both showed almost empty. I stripped down to my skivvies, hooked on a weight belt, put on one air tank and a mask, and slipped the canvas straps of the other tank over my arm. I picked up a crowbar out of the gear box.

"Anchor outside so one of them doesn't come up under the boat," I said.

"Leave the other tank. I'm going down, too." She had cut back the throttle, and the boat was pitching in its own wake. The side of her tanned face was wet with spray, and her hair was stuck to it.

"We need you up here, babe," I said, and went over the side.

"Damn you, Dave," I heard her say just as I plummeted with a clank of metal tanks through the water's surface.

The bottom of the Gulf was a museum of nautical history. Snorkel and scuba diving over the years, I had found clusters of Spanish cannonballs welded together with coral, U.S. Navy practice torpedoes, and the flattened hull of a Nazi submarine that had been depth-charged in 1942, a cigarette boat that dope runners had opened the cocks on before the Coast Guard had nailed them, and even the collapsed and twisted wreckage of the offshore oil rig on which my father drowned over twenty years ago. It lay on its side in the murk in eighty feet of water, and the day I swam down to it the steel cables whipped and sang against the stanchions like hammers ringing against an enormous saw blade.