Both Treasure Island and Robinson Crusoe have seafaring adventure and an island as central elements of their plots. The historic language used in each is similar, and much of the same nautical terminology (stern, bow, aft, etc.) is utilized due to the aforementioned similarities.
The characters in both books are alike in only the most basic of ways: Crusoe is male, as are Long John Silver and Hawkins. Both central characters are seamen, or will try to become such, in the case of Hawkins. Just as Crusoe tries to survive on the desolate island, young Jim Hawkins is trying to survive as a lone boy in a world of men.
Obviously, both books were written by male authors of the period, and that masculinity is seen through the tone of each book. Each story helps us to gain a perspective into the seafaring world of the past. Perhaps a better comparison could be drawn, however, between Stevenson's "Kidnapped" and Defoe's "Robinson Crusoe," as better similarities exist.