This water tastes fresh, this must mean I am getting closer inland!
Ouch!! All of my men retreat from here this instant!
"Magellan even relied on the taste of the seawater to guide the fleet. As the water became fresher, he knew he was traveling inland, and once it turned salty, he realized he was approaching the Pacific on the western side of the strait." (Over the Edge of the World by Harper Collins)
"Magellan killed in the battle with local inhabitants." (Map of Magellan's voyage)
"[Magellan] had his right leg pierced by a poisoned arrow, on which account he gave orders to retreat by degrees" (Journal of Antonio Pigafetta)