The night grew darker and colder.
Oliver was still up on deck, wrapped in a museum blanket that had mysteriously appeared, feeling the sea breeze on his face.
Suddenly, there was a strange sound.
Not a crash, not a bang, but more like a long, gentle 'thump' and a shudder that ran through the whole ship, from top to bottom.
It felt like a giant beast had brushed past the ship, or like the ship had just bumped into a very big, solid wall of ice.
A tiny shiver went down Oliver’s spine.
Most passengers didn't seem to notice much, or they thought it was just a little wobble.
But Oliver, who had been listening to the crew, knew this was something important.
Quickly, crew members started rushing through corridors.
Their faces were serious, and they carried lanterns, checking different parts of the ship.
Oliver saw them go down below deck, where the big engines and special 'watertight compartments' were.
“What are watertight compartments?” Oliver wondered quietly.
He remembered reading about them in a book at the museum.
They were like separate rooms inside the ship’s bottom, with special doors that could close to keep water out, even if one part got a hole.
But soon, the serious faces of the crew told Oliver that something was very wrong.
He saw little puddles of water forming in places they shouldn’t be, even in the fancy corridors.
“Water is getting into the lower compartments,” he heard an officer say, his voice low.
The great ship had scraped against a giant iceberg, a huge floating mountain of ice that had broken off from a glacier in a very cold place.