(Fortune Magazine) -- Bill Donahue, 58 As a teenager, Donahue fell in love with classic wooden boats and never stopped learning to repair and restore them in his spare time. To make a living, though, he spent three decades in banking, much of that time in executive jobs at First American Bancshares (now part of Wachovia), then as head of his own consulting firm.

He sold the consulting business almost five years ago to finance his current venture, Annapolis Classic Watercraft LLC (www.uncommonboats.com), in Annapolis. At any given time Donahue and his crew -- two full-time staffers and an array of subcontractors with highly specialized skills -- are working on a couple of major restorations plus half a dozen or more smaller repair projects. "Late summer and early fall are a really busy time for us," Donahue says, because "people are trying to squeeze the last use of the season out of their boats, so if something breaks, they want it fixed now." His firm also acts as a boat broker. "We sell about a dozen a year, all antique. It's a small niche." But evidently a profitable one: ACW recently moved into a brand-new, 6,700-square-foot shop.

The biggest surprise? "This is the hardest job I ever had in my life. It's a lot of stress and really long hours," says Donahue. "Even when I had my own consulting firm, there were people under me to handle a lot of the details. But with this, it's different. From treating the business like a hobby to spending too much on advertising, you make some big mistakes at the beginning, and they come back to bite you really fast." Still, he has no regrets: "It's great fun. I think this is what I was born to do."

MY ADVICE

"BE PREPARED TO WORK HARDER THAN YOU'VE EVER WORKED IN YOUR LIFE."