It was believed that the driver of the Holden that had been towing the boat stopped in the southbound lane, perhaps to rectify a problem with the trailer, with the four-wheel-drive ramming the Holden while it was stationary.
"It then seems that the driver of the 4WD, who, given the amount of blood that was smeared everywhere, was presumably injured, decamped, possibly in the Holden with that driver," Mr Beddows said, leaving a small terrier in the vehicle.
It was given a bed for the night and handed over to animal welfare officers next morning.
The firefighters used an appliance to drag the 4WD clear of the southbound lane, and with the assistance of police manhandled the boat and trailer off the road.
"Those who were first on the scene had already acted responsibly and moved the boat so it was out of the centre of the highway and traffic could get past," he said.