"For a seemingly endless time he fought the sea" Rainsford fights against the current of the ocean for a long time as he attempts to make it to shore while swimming to Ship-Trap Island.
"Rainsford had fought his way through the bush for two hours" Rainsford must figure out how to utilize the environment of Ship Trap Island as he tries to survive the hunt and runs from Zaroff in the forest.
"He heard the hounds. Then he leapt far out into the sea" Rainsford jumps into the ocean to escape death and must fight the waves again. The story cycles back to where it started, as Rainsford begins and ends his expeperience in the sea.