OK, when the weather was good, they probably used flags. But what if the weather turned bad and the ships lost sight of each other. Columbus couldn’t say, “Meet me in Nassau a week from Tuesday”.
He didn’t. The captains of the other ships had a general idea where they were heading, or at least what heading they were on, and they kept in visual contact or were screwed. There are copious examples of ships becoming separated from their companions and never being seen again.
Columbus’s ships actually became separated on his first voyage, both in the Caribbean and on his way home. While the expedition was off Cuba, the Pinta, commanded by Martin Alonso Pinzon, became separated on November 21. Pinzon, who had had a falling out with Columbus, is believed to have wanted to look for gold on his own, although some say the separation could have been accidental.
Columbus went off to Hispaniola, where the Santa Maria was wrecked on December 25. Since the Santa Maria’s crew wouldn’t fit in the smaller Nina, Columbus left some of them behind in a fort. (They would later be killed by the Indians before Columbus could return.) The Nina and Pinta re-encountered one another on January 6, and headed back to Spain on January 8. The two ships were separated by storms near the Azores, and reached home separately, Columbus first landing in Lisbon, while Pinzon reached a port in Spain.
Ships would sometimes designate a rendezvous site in case of separation, but of course this might not be possible if they were sailing in unknown waters.
If Columbus were a teen-aged girl, he would have texted.
Im on the C LULZ