The MacGilvray Shiras was a ship owned by the Kinsman Transit Company. During the winter months, when Lake Erie was frozen, the ship and others moored at docks on the Buffalo River. As oftentimes happened, one night an ice jam disintegrated upstream, sending large chunks of ice downstream. Chunks of ice began to pile up against the Shiras, which at that time was without power and manned only by a shipman. The ship broke loose when a negligently constructed ‘‘deadman’’ to which one mooring cable was attached pulled out of the ground. The ‘‘deadman’’ was operated by Continental Grain Company. The ship began moving down the S-shaped river stern first and struck another ship, the Tewksbury. The Tewksbury also broke loose from its mooring, and the two ships floated down the river together. Although the crew manning the Michigan Avenue Bridge downstream had been notified of the runaway ships, they failed to raise the bridge in time to avoid a collision because of a mix-up in the shift changeover. As a result, both ships crashed into the bridge and were wedged against the bank of the river. The two vessels substantially dammed the flow of the river, causing ice and water to back up and flood installations as far as three miles upstream. The injured parties brought this action for damages against Kinsman, Continental, and the city of Buffalo. Who, if any, is liable? Explain.