That is, Captain Spark would be in charge of the boat for six hours, and then Mr.Carr would go on watch for the same length of time, until it became the captain's turn again.

In this way each one could get sufficient rest.
The two sailors, Bob and Mr.Tarbill were divided between the two heads of the watch, Bob and Tim Flynn being chosen by the captain.
The food had been carefully stowed away in the lockers, the captain's charts, chronometer and sextant were put where he could easily get at them, and as they had breakfasted before they set off on their voyage, there was nothing to do for several hours but to make themselves as comfortable as possible in the boat.
Had it not been for the worry over what might be the outcome, and had not the dreadful memory of the shipwreck been in all their minds, they might have enjoyed the sail.

As it was, no one felt very jolly.

Mr.Tarbill was particularly miserable, and was continually finding fault.
"Oh, dear! It's dreadfully hot!" he exclaimed when they had been sailing for several hours and Bob's Island was out of sight.

"I'm afraid I shall be sunstruck." "Get in the shadow of the sail.