It was based on a miscalculation.
What seemed to him a desirable sailing breeze was a cause of grave discomfort to half the party.
Simpkins began to give way in less than an hour.

He yawned, pulled himself together, and then yawned again.

After that he ceased to take any active part in the conversation.

Then Miss King began to lose colour.

Meldon, who was sitting forward with his legs dangling over the combing of the cockpit, winked at Major Kent.