“Whew!” Mia waved her hand in front of her face. Okay, they were beautiful but they were definitely outstaying their welcome.

Suddenly a huge tail shaped like a giant letter Y began to rise out of the water, dead ahead. Water cascaded off its two halves, which were the size of aircraft wings.

There was a whale right in front of them. Bear spun the wheel to turn. The tail rose up, and up, and up. The whale must have been standing on its nose. Then it began to slide down into the sea. The tail slapped down with a mighty crash, and water sluiced over the front deck. The whole boat rocked, from end to end and side to side.

Ursula had turned away from the whale in front – but now Mia saw another danger. A massive grey bumpy back was surfacing like a submarine just a few metres away.

“Whale coming up behind!” she shouted. Bear started to turn the wheel again, but too late. The enormous back slid closer and closer, and then there was a crunch and Ursula shook again. The boat span around in the water, with its two humans clinging on for dear life.

Bear pointed at a rope connected to a kind of winch next to the wheel.

“Release that!” he said. “Just let it go.”

Mia fumbled with the rope, while Bear did the same to a similar rope the other side of the wheel. Mia’s rope suddenly came loose and whizzed through her fingers. At the same time the sail at the front dropped down to the deck. The main sail dropped down a moment later as Bear released his rope.

The loose canvas waggled about in the wind.

Bear passed Mia a handful of bungee cords.

“See if you can tie the main sail to the boom, and the foresail to the rail, to stop them flapping. I need to inspect the damage.”

It wasn’t easy, but Mia worked out how to do what Bear had asked. She could bunch up a bundle of sail canvas in her arms, and press it to the boom, and then wrap the bungee cord around it. She did the same with the front sail – what Bear called the foresail – tying it to Ursula’s rail.

The whales had all passed by and Mia and Bear were alone in the sea again. Suddenly a hatch in the deck at Mia’s feet flew open.

Bear was down below, pushing up a large canvas bag with both hands.

“Can you take this, please?”

Mia helped drag the heavy bag up onto deck. Bear clambered up after it.

“That first knock split some planks just behind the bow,” he said. “Water’s coming in below.”

Mia stared.

“You mean – we’re sinking?”

“Only very slowly. Let’s make it even slower.”