WASHINGTON -- Supreme Court justices on Monday jousted and even joked a little as they confronted a Florida floating home dispute that could shape U.S. maritime law.

The hour-long oral argument left no obvious winner or loser in the case pitting the town of Riviera Beach, a town in Palm Beach County, against former commodities trader Fane Lozman. The argument did, though, expose the potentially broader stakes, as well as the willingness of the justices to entertain possible scenarios ranging from inner tubes to rafts.

“It’s kind of a fun case for them,” Stanford Law School professor Jeffrey Fisher said after the oral argument. “They played with the hypotheticals.”

Fisher represents Lozman, a 51-year-old former Marine Corps officer who owned the floating home in question and docked it at the Riviera Beach marina. The rectangular “structure,” as Fisher called it, lacked an engine, bilge pumps, navigation aids, lifeboats or other devices that usually characterize waterborne vessels. It was equipped for connection to land-based sewer lines and received its power through an extension cord.

But Riviera Beach officials, following extended conflict with Lozman, employed U.S. maritime law in 2009 to seize Lozman’s home as a vessel. They subsequently had it towed to Miami, where they bought it at auction and then had it destroyed.

“The city faced a very real specter of being sued if the uninsured houseboat [became] unmoored and caused damage,” attorney David C. Frederick, representing Riviera Beach, told the court. “Our position is that the houseboat is a vessel … because it floats, moves and carries people or things on water.”

Enter the hypotheticals, some of them seemingly hostile to Riviera Beach’s legal position.

Chief Justice John Roberts Jr. pressed Frederick on whether the city would also deploy federal law to regulate inner tubes. They carry people on water, Roberts noted, adding that floats carry people, too.

“Most of the body parts of a person would be underwater and would be through the water,” Frederick said, seeking to draw a distinction.

That prompted the justices to suggest a dizzying array of other vessels potentially subject to regulation under the city’s theory. Justice Stephen Breyer asked about regulating a cup that floats, Justice Sonia Sotomayor asked about a floating garage door. Justice Elena Kagan suggested: “Take the inner tube and, you know, paste a couple of pennies on the inner tube. Now it carries things. There are things on the inner tube, and it floats.”

The Obama administration is siding with Lozman, arguing that the test of whether a structure can be regulated as a vessel depends on its “objective purpose or function,” rather than simply on whether it can float. The court’s ultimate decision on what a vessel is will affect the activities of a number of federal agencies, including the Labor Department and the Coast Guard, administration lawyers said.

“If it is permanently moored to the shore and is never going to sea again, then it’s not a vessel,” Breyer stated.

“That’s true,” Assistant Solicitor General Curtis Gannon said, adding that “something that used to be a vessel can cease to be a vessel if it is semi-permanently or indefinitely moored.”

Neither Fisher nor Frederick would predict after the argument how they think the court will eventually rule. The court is expected to issue its decision before the newly opened term expires next June.