Tilman J. Fertitta, the U.S. ambassador to Rome, is summering on his superyacht as President Trump squabbles with Prime Minister Giorgia Meloni of Italy.

Ronald L. Fischer vanished just before he was convicted. After more than 20 years on the run, he was arrested on a sailboat in the East River, the authorities said.

While grand ships with billowing sails made their way in the Hudson River, a crew in a modest tugboat kept watch on the high-traffic day on the water.