Then he touched something round and knew that a roller had been put under the canoe in order that she might be pulled up without disturbing the cargo.
This was a stroke of luck, because it would help him to run her down.
He touched Drummond, and getting up seized the gunwale.

They strained their muscles, but for a moment or two could not move the craft; then the roller jarred across a stone, there was a crunch of gravel, and she stopped, a foot lower down.

Thirlwell gasped and moved his hands to get another grip.

He thought they had made an alarming noise, but it was too late to be cautious.

They must finish the job.
"Lift her as you shove!" he said.
She went a yard, with the roller jolting in the sand, and there was a splash as her after-end took the water.