What significant item does Gulliver use to help him navigate Lilliput?

The correct answer is that Gulliver uses a compass to help him navigate Lilliput. As a skilled navigator and ship's surgeon, Gulliver relies on the compass not only for its practical function but also as a representation of his maritime knowledge and experiences. The compass helps him orient himself in an unfamiliar environment, which is critical when he finds himself in the strange land of Lilliput after being shipwrecked. While the other items listed, such as a map or sextant, may be useful in navigation, they do not play a role in Gulliver's journey in Lilliput as prominently as the compass does. A giant pocket watch, while interesting, is not relevant in the context of navigation in this particular narrative.