CHICAGO (CBS) — On frozen Belmont Harbor sits a maritime mystery.

A sailboat left floating at the dock at the end of last season is now frozen in the ice-covered water, a curiosity to local ice fishermen, and people who pass by on the lakefront path.

The name on the boat’s stern (at least, we think it’s a name) is NJRDR. It’s not a registration number. That appears elsewhere on the vessel.

The main sail is still on the 30-or-so-foot boat, under a cover.

The sailboat is white, with a somewhat faded light blue stripe running along the upper portion.

For privacy reasons, the Illinois Department of Natural Resources would not release the owner’s name. Neither would Westrec Marinas, the private firm that operates the city’s harbors for the Chicago Park District.

Westrec did say the boat was abandoned, and the owner couldn’t be found. It’s unclear why the boat was abandoned – whether the owner died, or just lost interest – along with money – in using the boat.

If the boat survives the winter without being crushed by the ice, it would eventually be sold at auction.

A U.S. Coast Guard officer said there are any number of things that could happen to the boat in the ice, which was measured recently by ice fishermen to be about 10 inches. The hull might be crushed by the ice, or it might pop up out of its icy prison, if conditions are right.