Thomas begins to think that this is how it will end: they will be drowned in a cog with some Easterlings off the Welsh shore, the roar of the wind in their ears and the taste of brine stopping their mouths. It would be easier to cease now, he thinks, to put aside his bucket, to say his prayers, face the truth. It is only the sight of Katherine that pushes him on. Her hair is plastered over her narrow head and her brittle little shoulders are pumping away as she scoops out the water with a wooden bowl.

On it goes, through most of the afternoon and into the evening, until at last the pitch of the wind eases. The rain hesitates, falters. Thomas looks up. Is it his imagination, but is the next wave shallower, the climb less arduous, the subsequent dive less deep, the rush of water across the deck less powerful? He seizes on the difference. Takes new heart. Digs his bucket into the churning broth and begins again. Soon they are managing to scoop more out than is coming in.

The crew give a muted cheer. They too guess the little cog has made it. They carry on bailing through the night, dipping, lifting, pouring, and by the time they stop Thomas is dizzy and his fingers are bleeding, but the cog is still afloat, and they are still alive.

They sleep all that night and the next morning breaks clear, just a bar of purple cloud across a sky the colour of a dove’s breast, and a steady breeze from the southwest. There is nothing to mark the passing of the storm except a quantity of driftwood in the sea. Then there is a body, floating face down, a man in a pale coat and blue hose.

‘Someone not so lucky,’ is the cog master’s opinion. ‘Keep eye out for survivors.’

But there are none, only more wreckage, a terrified rat on a barrel bobbing in the water, and then a shred of sail. Is it green? Katherine watches it pass, frowning hard, saying nothing.

The land is a shadow on the horizon. The mate, a purple bruise the size of a duck’s egg on his forehead, gets the crew to unfurl and set the sail and the cog master shouts a tired order and gives a heave on the tiller. The canvas slaps for a moment, then tautens and the cog collects herself, and turns in the dimpled green water, and they head northwards, back towards the coast.

‘How far d’you think we’ve drifted?’ Thomas asks the cog master.

The man shrugs.

‘Day, maybe,’ he says. ‘Maybe two. We see.’

The sailors are still bailing out, but above them the seagulls are back.

‘Is good sign,’ the cog master says.

Thomas joins Katherine in the bows where she is letting the wind dry the woollen coat she’s refused to take off. She is scanning the sea.