On Saturday night, a routine Coast Guard safety check of a 50-foot Viking yacht ended with its owner under arrest for boating while intoxicated. Charles W. Robins, 50, of Westport, Conn., was intoxicated at the time the Coast Guard patrol pulled alongside the Insight, about a mile northwest of Montauk Harbor, officials said.Lt. Martin Betts, chief public affairs officer for the Coast Guard in the Long Island Sound region, explained on Monday that the agency conducts random boardings as part of its mission. “Usually these checks cover things like making sure there are adequate life buoys on board, and that the boat has proper documentation,” he said. This time, though, the process took a different turn.Mr. Robins, who was on board with two other adults and two children, allegedly failed sobriety tests. East Hampton Town police were notified, and the boat was brought into the harbor, where a member of the town’s marine patrol took over.“What is one glass of wine, a .08?” Mr. Robins reportedly asked the harbormaster. “I had two or three, I don’t know.” Police said he failed a second set of sobriety tests, this time on shore, before being arrested.At police headquarters in Wainscott, Mr. Robins consented to take a breath test, which reportedly produced a reading of .11. At his arraignment in the morning, he told Justice Steven Tekulsky he was an executive with Numis Securities, with offices in London and Manhattan, and that his job requires him to fly frequently to the United Kingdom. This made setting a return date for him to answer the misdemeanor charges, which include reckless operation of a vessel, difficult.Justice Tekulsky and Mr. Robins compared their calendars, searching for a Thursday, the court’s criminal-calendar day, when Mr. Robins was in the U.S. and Justice Tekulsky was on the bench, until they hit upon July 30.“Okay, it’s a date,” Justice Tekulsky said, setting bail at $350, which was posted.