The vessel, which was flying a giant Mexican flag and had 277 people aboard, then drifted into a pier on the riverbank as onlookers scrambled away.
Sailors could be seen aloft in the rigging on the damaged masts but, remarkably, no one fell into the water, officials said.
Sydney Neidell and Lily Katz told The Associated Press they were sitting outside to watch the sunset when they saw the vessel strike the bridge.
“We saw someone dangling, and I couldn’t tell if it was just blurry or my eyes. And we were able to zoom in on our phone, and there was someone dangling from the harness from the top for like at least like 15 minutes before they were able to rescue them,” Katz said.