The very first sentence awakens the reader's curiosity about the island. Whitney claims that it is a mysterious island:
OFF THERE to the right--somewhere--is a large island, said Whitney. It's rather a mystery--
Rainsford and Whitney continue to have a conversation about the island. Whitney claims that the crew has been rather tense since they have been in the area:
Didn't you notice that the crew's nerves seemed a bit jumpy today?
Rainsford agrees that the crew did seem a bit strange. There is obviously something dreadful about the island. Even the Captain is concerned as they pass through the area. He confirms that the "place has an evil name among seafaring men...."
Whitney and Rainsford continue to talk about the superstitions of the island. It is a black, moonless night which makes things seem even more eerie. The reader is definitely curious at this point. Also, there is a fear that captures the reader's attention when Whitney and Rainsford talk of the evils of this island.
There is a doom and gloom present in Whitney's and Rainsford's conversation at this point. The fear of the unknown is real. Whatever is on that island is dreadful. Whitney definitely peaks the the reader's interest by his eerie details of the island. He shares more of his conversation with the Captain speaking first as they pass through the area:
'Don't you feel anything?'--as if the air about us was actually poisonous. 'Now, you mustn't laugh when I tell you this--I did feel something like a sudden chill.'
Whitney admits that he felt an eerie chill. There is something dangerous about the island. The reader is convinced of the dangers that exist on the island. The last thing one would want to do is to fall off the yacht in this God-forsaken area.
Also, the name of the island is "Ship-Trap Island". That doesn't exactly inspire confidence in the reader that everything's going to be okay.