For the next few minutes Win and I take it in turns to look at the Beulah and watch the baboon crew lolloping around the deck. I’m hoping we might catch up with them and even go on board, but a fog drifts across the sea and soon she vanishes from sight.

“Ahoy there!” shouts Rose. “Trim the sails. There’s a fearsome haar blown in!”

I peer down at her. “What?”

Even from up here I can see her roll her eyes. “It’s getting foggy, Arthur. Take in the sails. We need to slow down!”

“Aye, aye, cap’n!”

Soon the sails are slack and the Bowt is creeping slowly through the cold fog. Win and I are still in the crow’s nest. Our hoods are pulled low over our heads and we’re both grateful for our moon boots. The fog is thick. Win’s standing close to me, but he’s almost invisible in his white furry suit.

Wordlessly we pass the telescope between us, but the fog is so dense I doubt we’d spot anything until we were on top of it. This makes me nervous and thoughts of the Titanic and icebergs flit across my mind.

“Arthur . . . ,” says Win. “Can you hear something?”

I hold my breath and listen. I pick out waves striking the hull . . . ropes snapping . . . the groaning of the ship . . . but the groaning is too loud. There’s something about the creaking that doesn’t match the slow pace we’re moving at.

I lower the telescope and turn in a circle, trying to see into the fog that swirls around me. The groaning gets louder.

Suddenly, a dark shape looms out of the fog. The shape grows bigger and bigger, until I see masts and sails. A man-of-war is bearing down on us like a beast hunting its prey.

“Ship!” I yell. “SHIP!” Win starts to ring the warning bell, and he doesn’t stop.

“What’s wrong?” Rose looks up, panic written across her face.

I point desperately behind us. “There’s a massive ship! It’s chasing us! What shall we do?”

Win stops ringing the bell and grabs hold of my onesie. “It’s got orange sails, Arthur, and loads of orange monkeys are watching us!”

No, those are amber sails. This is Alisha, my A ship. And the monkeys glaring at us from the rigging are orangutans. She was the biggest and the most deadly of all my ships, and when I first made her up I wasn’t that good at spelling.

“Let out the sails!” Rose shouts. “We’ll try to outrun her!”