1--DRY SUIT
The watertight Mobby's Discovery Dry Suit protects McLain during his 4-hour stretches in the 50-odd-degree water of San Francisco Bay. Chafing pants guard against jagged debris.

2--WEIGHT SYSTEM
McLain wears up to 50 pounds of lead on a Miller weight belt. (A spring-loaded buckle facilitates one-handed escapes.) He also inserts steel plates in his boots and straps on 5-pound ankle weights. The result? Around 95 pounds of gear--and a man who's much happier underwater.

3--FIBERGLASS HELMET
The Kirby Morgan SuperLite 27 helmet is rigged with a microphone and speakers, flashlight and chrome-plated brass closures. At 37 pounds the SuperLite weighs about half as much as old-style metal helmets.

4--HYDRAULIC CHAIN SAW
The Stanley CS06 Underwater Chain Saw helps McLain level rotten piles; the Stanley drill at his feet bores holes for the pins that anchor new piles to the remaining stubs. Wielding power tools in silty "black water" is the diver's riskiest task. "Most of our work is by feel," says McLain.

5--TORCH
McLain cuts steel with the Broco BR-22 Torch, which shoots oxygen through a magnesium rod that hits 10,000°F. The unit uses an electrical charge--which travels through the water. "It'll wake you up," McLain says.

6--RACK BOX
The Amron Amcommand II unit contains a depth gauge, an air-pressure control that sounds an alarm when a diver's air drops to 100 psi, and a two-way radio. The 400-ft. media cable that connects to the helmet is military surplus.

A BAD DAY AT WORK?
"You can get fouled in a net, tangle your hose on a pile, have a mudhole cave in on you," says McLain. Worst case? Cutting the hoses. Then, "it's a one-man show. No air. No communication. I have 3 to 5 minutes of oxygen in my suit." Just enough time to weigh the options.