The tides have recently returned smooth music from its ’70s and ’80s island outpost to an eager and growing audience. Steely Dan and Hall & Oates are hot again. Jazz bassist Thundercat recently released a song with guests Michael McDonald and Kenny Loggins. The resurgence of so-called yacht rock was given a Crescent City twist by the dapper band Where Y’acht, masters of musicianship, neckerchiefs and piña coladas.

“I had the name for four years and was trying to put the band together,”...