HARRISON TOWNSHIP, Mich.  So many people have so many things they can no longer afford. This is an excellent time to be a repo man.

When a boat owner defaults on his loan, the bank hires Jeff Henderson to seize its property. The former Army detective tracks the boat down in a backyard or a marina or a garage and hauls it to his storage area and later auctions it off. After nearly 20 years in the repossession business, Mr. Henderson has never been busier.

“I used to take the weak ones,” he said. “Now I’m taking the whole herd.”

Boating was traditionally the pastime of the well-off, but the long housing boom and its gusher of easy credit changed that. People refinanced their homes and used the cash for down payments on a cruiser, miniyacht or sailboat. From 2000 to 2006, retail sales for the recreational boating industry rose by more than 40 percent, to $39.5 billion, while the average loan amount more than tripled to $141,000.

Last year, as real estate faltered, the gears went into reverse. The number of boats sold fell 8 percent. Many boats are fuel hogs, and rising gasoline and diesel prices meant a weekend jaunt could cost hundreds or even thousands of dollars. Owners found they could not sell a boat for what they owed and could not refinance either.