Capt. Jack Schachner strained his eyes as the waves crashed over the rail of his towboat. It was a moonless night in Jamaica Bay and a storm had pitched the black water, making the conditions even more dangerous than usual as he sped along a rocky stretch of shoreline in pursuit of his bounty.

And suddenly there it was, illuminated by the flashing orange lights from his boat: a 53-foot fishing vessel listing perilously and quickly taking on water from a large hole torn across its hull. The accident had occurred in the dark, prompting a Fire Department rescue of four passengers thrown into the water and leaving the boat dangerously situated on a rock jetty.

Schachner’s job was to tow the boat somewhere safer, where it could be left until he could orchestrate its removal. For an entire night, he worked alone, his boat groaning angrily as the waves slammed it against the damaged vessel. Despite the peril, the thought of leaving never surfaced in his mind, he said. His reward for this salvage, he estimated, would be at least $30,000.

Captain Jack, as he is universally known at Gateway Marina in Sheepshead Bay, is a professional boat salvager and, along with his brother, Capt. Bernie Schachner, is a co-owner of White Cap Marine Towing and Salvage Inc. Summer is their busy season.

He waits for warm weather to lure New Yorkers seeking relief on yachts, motorboats, sailboats, kayaks and Jet Skis. Then he waits for them to get themselves in trouble.

The waiting occurs largely at his "office" at the Marina — a floating, motorless houseboat, with his towboats tethered nearby, ready to race to a rescue or a salvage at a moment’s notice. The crackling sound of a VHF marine radio follows him wherever he goes — they are installed in his car, next to his bed and in his kitchen and when he heads out to buy groceries he clips one to his belt. Each is tuned to Channel 16, the so-called hailing and distress channel.

"I can tell when there’s a sense of distress, of panic in someone’s voice, even from sleep," Schachner said with pride, standing on the back of his houseboat in a black T-shirt with the sleeves cut off, a shark tattoo fighting through the tan of his right shoulder. "And when I get that sense, I go."

He needs the radios because speed is essential in his business. Maritime salvage laws, created more than a century ago to give a mariner incentive to assist a vessel in peril, state that the rescuer is entitled to a salvage reward. The reward, typically paid by insurance companies, is calculated based on a percentage of the vessel’s value and cargo, and on the dangers faced during the salvage. The greater the danger, the higher the reward.

For the brothers, two Navy veterans with a love of adventure and "saltwater running through our veins," salvaging seemed a natural calling, Jack Schachner said.

Along with their first mate Frank Donnelly, they have faced their share of dangerous salvages. And are more than happy to do so. Several years ago, for instance, an 87-foot clamming boat ran aground off the coast of the East Rockaway Inlet with over 6,000 pounds of clams on board. The rescue started smoothly until the heavy boat started listing and nearly dragged the brothers’ towboat under water. A frantic last-minute scramble prevented both boats from sinking.

"They offered to pay us 20,000 clams. Not slang, but, like, literally, clams. Like I could sell them or eat them," Bernie Schachner said, laughing. "But after that rescue, only money would do."

While the high-octane rescues make for great dock stories, most days are filled with smaller-scale tows and salvages. The ever-shifting sand deposits act like flypaper to the hulls of boats navigating Jamaica Bay. Most of the boaters in New York’s waters, Bernie Schachner said, are inexperienced and have never taken a class or gotten a license. New York state will not require a boating license until a new law goes into effect in May 2014. Some boaters simply run out of gas.

"All it takes is a credit card for an idiot to buy a boat and kill people," Bernie Schachner said. "But if it weren’t for idiots, I wouldn’t have a job."

Yet even the most knowledgeable sailor sometimes runs aground.

"This is the picture the Coast Guard doesn’t want me to show," Jack Schachner said, holding an old picture of a Coast Guard vessel grounded on a sandbar, tilting about 30 degrees to the port side. "But anyone that has said ‘I never went aground’ is a liar. I’ve probably towed everyone in this marina, at one point or another."

Minutes later, he received a call from Haim Boiangiu, a self-proclaimed "repeat customer," whose sailboat’s motor failed and who needed a tow back to the marina. Boiangiu, an experienced sailor, showed no sign of embarrassment, loudly playing opera while he tethered his boat back to the dock and gave his insurance information to Donnelly.

Afterward, Schachner slowly motored back to his dock and houseboat. He was loudly greeted as he passed by another sailor lounging on his boat in the sun.

"Hey, Captain Jack! Making a lot of money today?"

"Nah, I’m waiting for you to wreck that thing you call a boat!"

He chuckled as he eased his boat back into the dock, swinging the stern around as if he were parallel-parking a car, and leapt onto the dock and walked toward his houseboat, radio in hand, to wait for the next call.

© 2013 The New York Times Company