Before he turned 20, Bill Rosen was a veteran of three trans-Atlantic yacht races. As paid crew aboard such ocean-racing yachts as Xanadu II and the legendary Ondine, Rosen worked his way through college in jobs most sailors only dream about.

But given his background, it's not too surprising. Rosen, 28, grew up in a sailing family on Long Island and spent many of his young years racing dinghies on Manhasset Bay, real yachting country.

What is surprising is that someone with all that racing experience -- which also includes five Newport-to-Bermuda races plus half a dozen other big ocean events -- would fall in love with one of the most unconventional small cruising sailboats on the market today.

Bill Rosen is in love with the Dovekie, a picture of sea- going simplicity, economy and all-around common sense. It's the answer, he says, to the boating riddles of the '80s: It's inexpensive; carries a simple rig; has no engine to burn expensive fuel, stink or break down; sails in as little as four inches of water; can sleep four people in modest comfort; and is easily trailered behind a subcompact. But it's like no boat you've ever seen before.

Imagine a pointed fiberglass shoe 21 feet long with a mast and single sail sticking up from the instep. A fin juts down into the water on either side of the arch. Square hatches are cut through the tongue and the toe, and a seat is wrapped around the inside of the heel -- that's the cockpit.

Now look at what makes the boat go when the wind dies. Two rectangular ports are cut through the hull just forward of the fins (called leeboards) and a removable seat is placed between them. Out of the ports come -- surprise -- nine-foot oars. They don't smoke or make noise, they burn only carbohydrates and they'll never require the services of a mechanic. And they move this 21-footer surprisingly well: At three knots, Rosen claims.

A Dovekie weighs only 600 pounds and has a flat bottom, to allow easy beaching and an upright position when the tide goes out. And it also lets you pull the boat up easily on its specially designed, carpet-covered trailer -- no rollers to position or jam up. And the trailer allows you to launch and retrieve the boat without even getting the wheels wet -- no wheel bearings to repack.

The sail rig is also surprisingly simple: Technically, the boat is a Marconi-rigged catboat, since it has only a triangular mainsail, but a Dovekie uses a sprit instead of a boom. The sail is laced to the mast and they go up together when the mast is stepped on the cabin roof (the instep). The rig can be raised or lowered in two minutes, so fixed bridges are no problem -- and all that thin water upriver is open to you.

The leeboards, which provide the lateral resistance of a centerboard or fixed keel in most sailboats, pivot on the outside of the hull, leaving the cabin floor flat and unobstructed. The boards are raised or lowered to any angle by inside handles. Fully dropped, the Dovekie draws 2'6", yet -- depending on the direction of the wind -- the boat can be sailed effectively with the boards drawing a foot or less. The Dovekie has an outboard rudder with a pivoting blade that will kick up over obstructions.

"If it's blue, you can sail there," says Rosen as he prepares to sail out of a quiet, and very shallow, anchorage in which a raft of Dovekies have just spent the night. Two more of these little ships ghost their way out of Dyer Creek on the light, early-morning air as another, oars outstretched like some miniature Phoenician galley, slides quietly in the opposite direction to explore the creekhead.

Dyer Creek is one of several enchanting little backwaters of the Eastern Shore's Sassafras River that a fleet of 10 Dovekies explored during a three-day weekend last spring. The event was one of a series of Dovekie rendezvous that take place rather informally each year.

In 1980, five Dovekies explored the nooks and crannies around Crisfield, and last year seven met at Kent Harrows for a cruise to Wye Island. This year, the Sassafras River expedition, organized by Rosen, drew boats from as far away as Massachusetts, Connecticut and North Carolina.

Possibly the most significant statement about the Dovekie was made silently that weekend in the parking lot of the Duffy Creek Marina in Fredericktown, Maryland, where fuel-miserly subcompacts bearing license plates from those far-off places waited with empty trailers.

The Dovekie was conceived eight years ago by Gloucester designer Phillip C. Bolger, partially to thwart OPEC both afloat and on the road. Bolger is generally regarded as something of an iconoclast among naval architects and he has come up with some surprisingly successful, if outrageous, designs -- like a 30-foot "folding schooner" that has a big hinge amidships so that it can be folded in half to carry on a trailer.

In 1974 Edey & Duff of Mattapoisett, Massachusetts, built the prototype of Dovekie, named by Bolger after a small, pelagic seabird. The firm went into production in 1978 and has sold 55 boats since. According to builder Peter Duff, most of them have found homes in the mid-Atlantic region.

What kind of person buys this striking, unique and -- well, odd -- boat?

Duff says his customers come in all shapes, sizes, personal interests and ages, including a 65-year-old woman who sails singlehandedly because her husband doesn't like boats, and a 75-year-old man for whom Duff rigged a winch to help raise and lower the mast.

And they keep coming. Duff says he gets six to ten inquiries a day and recently had a three-day run of 26 letters daily.

"I can see a market of 200 boats a year," Duff says, "but we can't supply it." The firm is now building at the rate of about 30 per year, but because it does not sell through dealers, potential buyers must either travel to Massachusetts to see the product or find a local owner who will show his boat.

But the direct purchase keeps the price down, too -- by about 20 percent, Duff says. A Dovekie sells for under $6,000 sailaway, with another $1,000 required for the specially designed trailer. And that seems to be where the spending stops.

"I defy you to spend any money on this boat," says Rosen, a procurement attorney with the Navy. "It doesn't need anything; it's all here and it's ultrasimple.

"I went into a marine store to get some things for my boat after I bought it last year and all I could buy were running lights; I didn't need any fancy hardware or other expensive accessories."

Perhaps the boat's biggest drawback is its unconventional appearance, a point Bolger makes in the chapter on the Dovekie included in one of his four four, books of boat designs. Written after the prototype was tested successfully, he wrote: "Whether Dovekie will be marketed in quantity is undecided . . . to say nothing of whether she'll sell if she is. The doubtful points are psychological rather than technical."

Now, though, the Dovekie may have the psychological advantage, too.