It was a seemingly lovely afternoon to go out on the East River and do something memorable. For the group that left the marina in College Point, Queens, on Sunday in a dragon boat, the authorities said, that was exactly the plan.

One of the men onboard was ready to propose to his girlfriend.

But soon after he popped the question, the authorities said, the fairy tale became more dramatic, as the wake from larger vessels passing by overwhelmed the dragon boat and capsized it. A rescue call was made at 1:39 p.m.

Lt. Robert Greer of the New York City Fire Department arrived at the scene about five minutes later. “It was shocking to see that many heads bobbing in the water,” he said.

By then, he said, the boat — a low-slung and narrow human-powered watercraft — was completely submerged.

In all, the authorities said, there were 19 people on the boat, all of whom had flotation devices. No one was injured.

Lieutenant Greer said that some pulled from the water were shivering and frightened. He, too, was concerned. He wanted to make sure no one was left behind. But all were accounted for and brought back to the College Point Marina.

As for the proposal?

“I hope she said yes after all that,” Lieutenant Greer said. “I’m pretty sure she did say yes.”

He said the couple had looked jubilant as they returned to land, and not just because they were out of the water. Later, he saw the man bend down on one knee in a re-enactment. With such a harrowing beginning for their engagement, Lieutenant Greer predicted, “it can only get better from this point.”

“It should be smooth sailing,” he said, “if you’ll excuse the pun.”

In another boating mishap on Sunday, a man was rescued after his canoe capsized in the Hudson River near the Riverdale Yacht Club in the Bronx.

Martine Baum, a steward at the club, said in a telephone interview that the Fire Department and a boat from the club had rescued the man.

“He was rescued almost immediately,” Ms. Baum said. “Everything is O.K.”