About 18 years ago, a California fisherman named Chester Buethe decided he could build a better boat dock.

He built a floating dock of laminated wood planking -- a dock that lies on the water like an enormous tree with boat slips formed by its branches, with the strength and flexibility to withstand waves and tides as a tree survives a storm.

"We tell customers it works like a tree," said J. Keith Larson, president of Marinas Internationale Ltd., the company that bought the fisherman's system and has used it to build about 200 marinas worldwide. "A tree can last 200 to 300 years, bending back and forth in winds and in storms."

Marinas Internationale, based in the landlocked D.C. suburb of Herndon, grew out of the plans of a McLean developer who wanted to build a real estate project with a marina.

Seven years ago, Dwayne Stevenson was looking for a marina design for his project when he came across Buethe's system of floating wood-planked docks.

Stevenson's real estate plan never made it to the construction stage, but he bought the system and went into the marina business. The privately held, stockholder-owned firm has grown since then from a two-man operation to a company with more than 25 employes and annual sales of more than $10 million, Larson said. Stevenson is a major stockholder and sits on the board of directors.

Marinas is one of the top five builders of floating docks that markets its expertise on a national basis, industry experts say. About 30 firms across the country build or supply equipment for floating and fixed marinas, according to the National Marine Manufacturers Association.

The company serves as architect, contractor, developer and manager on the water, offering clients services needed to guide a marina from idea to operation.

With six offices in the continental United States and finished projects scattered from Delaware to Hong Kong, Marinas offers services that begin with an evaluation of a proposed marina site.

If a water basin is appropriate for marina development, the firm can propose layout, refine it into an engineering plan, organize and supervise the construction and run the marina when completed. Besides the dock walkway and boat slips, a marina design can include elements such as a manager's office, a convenience store, fire suppression systems and arrangements for utilities, sewage disposal, cable TV and telephone service.

The company offers assistance in securing state and federal permits, finding local engineers with the needed expertise, providing design information to government authorities and altering the design to win approval if necessary.

"Marinas are more than docks," said Larson, a power-boat fan who says most of the company's management has some boating experience. Marinas Internationale does believe, however, that its docks are among the safest because of the Buethe system.

Unlike fixed docks, a floating dock can rise and fall with the tide, providing easy access to boats. A floating marina is required for sites where the water is very deep or the tidal range is very large, said Clint Chamberlain, manager of the marina design division of Warzyn Engineering Inc. of Madison, Wis.

Floating marinas are more common in the lower Chesapeake Bay, nearer the ocean, than in the upper area because of the difference in tidal conditions, said Al Simon, a spokesman for the National Boating Federation, a nonprofit association of boat owners.

Winter storms blowing water out of the lower bay reduce the water level and can leave a boat hanging by a rope tied to a fixed dock, while spring floods can submerge a vessel tied too securely, Simon said.

Marinas also contends that its laminated wood planking can give and bend slightly with the elements, unlike solid surfaces made of materials such as concrete, aluminum or fiberglass.

"Other systems are very solid and rigid," Larson said. "They work against the forces of nature and can be destroyed. Ours works with the forces of nature."

Some docks are built of segments connected with hinges to allow for sway and movement, but Larson promotes the Marinas system as better.

"A tree is not segmented; it bends all the way down so the forces are absorbed throughout. Our docks are engineered as one piece with many branches."

However, Chamberlain, of Warzyn Engineering, said various types of marina technology are appropriate under different conditions. "All makers feel they have a good system. . . . But what is good in one situation is utterly wrong in another," he said.

The choice of a dock material depends on a combination of factors, including aesthetics, weather, maintenance, durability and engineering considerations, said George R. Rounds, director of association services for the National Marine Manufacturers Association.

Marinas uses various types of pine, hemlock and cedar, cut in 2-by-4-foot or 2-by-6-foot planks and treated with a substance to prevent decay.

"Laminated wood does cost more," Larson concedes. A typical 200-slip Marinas Internationale project, including floating piers, a manager's office, showers and lockers, restrooms and sewage pump-out system, would cost about $1.7 million, according to company estimates.

The tree-like dock can grow to fill any size water basin, Larson said. The South Shore Harbor marina in Clear Lake near Houston will have slips for 2,000 boats when completed, making it the largest privately owned marina in the country, Larson said.

South Shore is the company's flagship marina, partly because of its size, but primarily because it survived the rage of Hurricane Alicia, which pounded the Texas Gulf Coast in August 1983.

The newly opened marina, with slips for 500 boats at that time, was unharmed by the 100 mile-per-hour winds and rose with the 10-foot tide. The company says that, of more than 400 boats berthed at South Shore during the storm, none suffered serious damage.

Marinas Internationale currently is riding a rising tide of construction activity in the United States, after weathering the recent rough periods of high inflation, high interest rates and recession.

"Things are picking up," Larson said. "We're affected by the decline in interest rates, just like the construction business. Marinas are amenities to other projects. . . . If developers can't borrow money, we can't build marinas."

About 3,000 boat slips were built in this country during each of the last two years, said Chamberlain, adding that his firm alone is planning to design 4,000 this year. And the nation's largest marina firm, Meeco Marinas Inc., based in McAlester, Okla., said its business has increased about 50 percent over the level of activity of three years ago.

One aspect of the general economic recovery that has favored marina construction is that people in the upper-income brackets -- those who can afford large boats -- have prospered, Chamberlain said. Manufacturers of smaller boats, the 10- to 20-foot vessels often stored on trailers, are "not doing as well."

Another reason for the increase in marina construction is the "growing awareness of municipal governments, large and small, that a marina is a definite asset," said Rounds, of the National Marina Manufacturers Association, noting successful waterfront redevelopment projects in cities such as Baltimore, Philadelphia and Boston.

In November, Marinas Internationale began installing 188 floating boat slips at Boston Harbor's Shipyard Quarters Marina.

Other current projects include the Waterfront City Marina in Kuwait, one of six projects completed or planned in the Middle East. The company also has projects in various stages of completion in the Caribbean, Singapore and Hong Kong.

Marinas Internationale has the largest number of overseas projects of its half-dozen competitors, Larson said. It wants to expand overseas by establishing sales agents in the United Kingdom and Mexico this year and in the Mediterranean next year, he said.

The company's Washington-area headquarters is convenient because it is near Dulles Airport and is centrally located on the Eastern seaboard, Larson said.

Anyway, "you don't have to be on the water to provide services," Larson said of the company's location. "You could put it anywhere."