Divers spent another day combing the waters of St. Ann’s Bay, but they have yet to find a car that plunged off a cable ferry and into the bay Monday night.

RCMP say the divers are using a side scan sonar device, which emits fan-shaped pulses to create an image of the sea floor.

“This instrument can pick up any images under the water,” says Staff Sgt. Craig Yorke of the Baddeck RCMP. “It’s viewed from the deck of the fishing vessel. Those images should be able to identify a vehicle or body.”

RCMP Sgt. Alain LeBlanc says the car drove from a dock onto the Englishtown Ferry and picked up speed before plunging off the end of an upright ramp at around 8:45 p.m. Monday.

“The person working on deck tried to gain the attention of the driver by tapping on the window to get his attention, but the person continued on through the gate and over the side,” says Yorke.

The car landed in the water, about 20 to 30 metres from shore, and was last seen about 200 metres from where it entered the bay.

The make of the car or the number of occupants inside remain unknown.

Adding to the mystery, police say no one in the area has filed a missing persons report.

“There’s very little information,” LeBlanc told CTVNews.ca on Tuesday. “It happened very fast and the ferry crew didn’t have a lot of time to look at the car.”

“It could be somebody from out of province, somebody from the U.S.,” says Yorke. “It could be someone travelling in a rental car.”

The divers have now spent two full days combing the bay, but their efforts have been hampered by its fast-moving current.

“The undertow there is ridiculous,” says local fisherman Keith Burroughs. “It’d pull you away in a second, as soon as you hit the water.”

Search efforts have been concentrated mostly on an area where an oil slick was spotted Tuesday morning, but weather has prevented some spots from being searched.

“The wind, current, and freezing cold temperatures of the water, and we have an ice flow that’s coming in…once that comes in, it’s not going to be safe to dive any further,” says RCMP diver Const. Darryn Sampson.

At this point, search crews believe the submerged vehicle has only been carried farther away by the strong current, lessening the chances it will be found anytime soon.

“If it stayed neutrally buoyant, it could be below the surface, maybe 15 to 20 feet,” says Sampson. “If it floated 300 to 400 feet, from there it could have gone out even further, further from the area we’re looking in right now.”

There is no word at this time on what caused the vehicle to plunge off the ramp.

“Anything could have happened,” says Yorke. “We don’t know what was going on in the mind of the individual at the time, or if it was a medical problem or what.”

Police say they won’t know what happened until a body is found, but they remain hopeful for answers.

“Eventually the car’s going to fill with water and going to sink to the bottom, wherever that is,” says Sampson. “It’s a 99 per cent chance it’s going to stay right there.”

RCMP say they don’t know how long the search will continue, but a decision will be made at the end of each day.

The Englishtown Ferry, which links the communities of Englishtown and Jersey Cove, went into service in 2008.

It will be out of service until further notice.

With files from CTV Atlantic's Ryan MacDonald and CTVNews.ca