Manitowoc, Wis. ? David Ross slips off his loafers and climbs aboard the giant boat floating on the Manitowoc River.

Shoes can scuff the deep red onyx flooring on the Mirgab V, a 144-foot yacht built by his company, Burger Boat, for a family from Kuwait. All workers must remove their shoes – those making final tweaks on a glass elevator, or ensuring the lighted treads on a three-story bronze stairway stay bright, and others hooking up DVD and stereo systems to a projection screen.

In the next two weeks, the yacht, with its 8,100-square feet of living space, is expected to depart for the Mediterranean. The culmination of two years building the yacht marks a turning point for Burger Boat – it’s the biggest yacht ever built by the company. And the projects only get bigger from here, said Ross, the company’s president.

Boat builders around the country are making larger boats and moving into the yacht category, which is anything exceeding 28 feet, said Thom Dammrich, president of the National Marine Manufacturers Assn., the trade group for the recreational boating industry.

For Burger Boat, the average boat size has stretched to 147 feet from 104 feet in 2003. Now business is booming at the 143-year-old company’s shipyard in Manitowoc, about an hour north of Milwaukee. There are seven yachts in various stages of construction – a process that can take two or more years – and four other projects are in the works, he said. The boats will sell for $15 million to $50 million when they’re complete.

The Lady Pat, a yacht built by Burger Boat, is seen in this 2005 file photo. For Burger Boat, the average boat size has stretched to 147 feet from 104 feet in 2003. The Lady Pat, owned by Ralph and Pat Horn of Memphis, features five staterooms, granite countertops and a teakwood deck.

Customers who already own boats want larger ones, and often they want to stick with the same brand, so companies at all size points are lengthening their boats, Dammrich said.

“It’s what the customer is demanding, so you’ve got to do it,” he said.

Starting out small

People often start with smaller boats then move up to larger ones as they become more involved in the sport, said Dusty McCoy, chairman and CEO of Brunswick Corp., the world’s largest manufacturer of pleasure boats and marine engines, based in Lake Forest, Ill.

“There is a phenomenon in boating where people do come into boating in smaller sizes, really enjoy it as a recreational activity and things get larger,” McCoy said. “They begin to understand the family possibilities, the entertainment possibilities, the enjoyment possibilities, and they begin to buy larger boats.”

Ralph Horn and his wife, Pat, owned a 65-foot boat for two years but decided to go bigger two years ago after they realized how much time they spent on water.

Horn, 65, had retired early after a career in the banking industry, and the couple couldn’t decide where to spend their retirement.

“We didn’t have a place to go to in the winter, and we couldn’t find a spot,” said Horn, of Memphis, Tenn. “Both of us agreed this is what we really want, so I said, ‘Let’s try a floating condo.”‘

In two years, they have gone boating at least one week a month to places such as the Grenadines, Maine and the Caribbean on their 98-foot Burger Boat, which has five staterooms, granite countertops in the kitchen and a full-time crew.

Horn said he’s been buying larger and larger boats ever since his first boat as a kid – four oil drums hitched to a piece of wood with wire. Now he spends his time entertaining friends and family on his favorite part of Lady Pat, an 11-foot teakwood deck overlooking the water. He’s got no plans to upgrade again just yet.

“I’m just as happy as I can be,” he said. “We have the perfect boat for us.”

Kansas competition

Power boat sales, which includes any boat with a motor, were $9.4 billion last year, but while units were down less than 1 percent from 2004, spending was up 4.4 percent, according to the NMMA’s annual report. Sales are expected to be flat this year, Dammrich said.

Considering that the average American boat is 25 feet long and costs $25,000, megayachts still comprise a small part of the American boat market, he said. There are between 12 and 20 such manufacturers nationwide, Dammrich said, and there are only 250 of these boats produced worldwide each year.

And new rivals are appearing.

Cobalt Boat, which makes boats in the 20-foot to 30-foot range, recently built a factory in Tennessee for its new venture into yachting. It will make yachts between 42 feet and 52 feet initially and then gradually increase size, possibly into the 70-foot range, said Shireen Fitts, a spokeswoman for the company based in Neodesha, Kan.

“I believe this market is continuing to grow,” Ross said.