Picture this: a property owner you rent from decides to sell to a developer who intends to convert the property to a condominium.

Nothing unusual about that, right?

Not unless the property in question is a marina, the units are boat slips, and the tenants are boat owners.

Several hundred boaters on the Chesapeake Bay have found themselves in just that position over the past few months, as two existing marinas have converted to condominiums and a third is being built as a condominium.

Converting marinas to condominium status is not a new idea. It's been done in other parts of the country with mixed success, but the idea only came to the Bay last summer.

As with most investments there are pluses and minuses to weigh.

Piney Narrows Marina, now known as Piney Narrows Yacht Haven, is located on Kent Island on Maryland's Eastern Shore and is the first Bay marina to attempt a condominium conversion.

Piney Narrows was followed late in the year by the largest marina in Maryland, Bowley's Point Yacht Basin, now called Bowley's Quarters Condomarina.Bowleys is located north of Baltimore, on the Middle River.

A third marina, Flag Harbor Yacht Haven, located in Maryland's Calvert County, in the Long Beach area near St. Leonard, is not a conversion but is being built as a condominium.

Owning a condominium marina boat slip in many ways is very similar to any other kind of real estate investment. In a number of ways, however, it is a bit bizarre.

A boat slip, no matter what it's called, is not more or less than a rectangular space in the water bounded on three sides by pilings and/or a dock, and open on the fourth.

Boaters themselves appear divided over the idea of condominium marinas. For some, owning a boat slip is appealing for the same reasons homeownership is attractive: growing scarcity of rental stock, rising rental prices, tax benefits.

A boater, or simply an investor, wanting to buy a condominium marina slip is faced with the same confusing choices as any prospective condo buyer: location, price, amenities and financing.

At Flag Harbor, prices range from $8,000 for an uncovered 30-foot slip to $13,750 for an uncovered 40-foot slip, with covered slips available as an option. A 40-foot covered slip would cost an additional $5,800.

Bowleys is selling 27-foot slips for $7,800, and prices go up to $15,800 for a 54-foot slip. The marina has no covered slips.

Piney Narrows prices are most expensive, ranging from $10,000 for a 30- to 35-foot open slip to $23,000 for a 60-foot covered slip.

At this point, financing for the three marinas is done through the developer. Lenders contacted in the area express little enthusiasm over the prospect of lending on a condo marina slip.

The president of a large savings and loan association in the area said his institution "wouldn't touch" a loan on a condominium marina slip because "we'd be too exposed for too little security."

Another S&L executive said his institution might make up to a 50 percent of value loan on a condo boat slip, but only to a borrower already known to the association, and "somebody we've had good experience with. If a borrower wanted to buy a boat slip," he went on, "I might try to get him to add this loan to his house loan, and then we might could do a little better than 50 percent. "It would be very difficult to make 'spot' loans in a marina," he said. "How could you foreclose on a single boat slip?"