why were the men grumbling??? what did they do when they saw the island

The men grumble because they do not want to work. Once they get close to the island they relax in their work.

The heat was sweltering, and the men grumbled fiercely over their work. Anderson was in command of my boat, and instead of keeping the crew in order, he grumbled as loud as the worst.

"Well," he said with an oath, "it's not forever."

I thought this was a very bad sign, for up to that day the men had gone briskly and willingly about their business; but the very sight of the island had relaxed the cords of discipline.

What were rhe men grumbling?what did they do when they saw the Island√?