A week after the bridge collapsed

A week after the bridge collapsed, Merthin had built a ferry.
Caris admired Merthin’s work. The raft was large enough to carry a horse and cart without taking the beast out of the shafts, and it had a firm wooden railing to keep sheep from failing overboard. New wooden platforms at water level on both banks made it easy for carts to roll on and off. Passengers paid a penny, collected by a monk – the ferry, like the bridge, belonged to the priory.
Most ingenuous was the system Merthin had devised for moving the raft from one bank to the other. A long rope ran from the south end of the raft across the river, around a post, back across the river, around a drum and back to the raft, were it was attached again to the north end. The drum was connected by wooden gears to a wheel turned by a pacing ox. A lever altered the gears so that the drum turned in either direction, depending on where the raft was going or coming back – and there was no need to take the ox out of its traces and turn it around.
‘It’s quite simple,’Merthin said when she marvelled at it – and it was, when she looked closely. The lever simply lifted one large cog wheel up out of the chain and moved into its place two smaller wheels, the effect being to reverse the direction in which the drum turned. All the same, no one in Kingsbridge had seen anything like it.
During the course of the morning, half the town came to look at Merthin’s amazing new machine. Caris was brsting with pride in him. Elfric stood by, explaining the mechanism to anyone who asked, taking the credit for Merthin’s work.
Caris wondered where Elfric got the nerve. He had destroyed Merthin’s door – an act of violence that would have scandalized the town, had it not been overtaken by the greater tragedy of the bridge collapse. He had beaten Merthin with a stick, and Merthin still had the bruise on his face. And he had colluded in a deception intended to make Merthin marry Griselda and raise another’s man child. Merthin had continued to work with him, feeling that the emergency outweighed their quarrel. But Caris did not know how Elfric could continue to hold his head up.
From the book ‘World without end’ by Ken Follet