What happened Shares of Norwegian Cruise Line Holdings (NYSE:NCLH) took a tumble on Thursday after the cruise line operator announced plans to sell as much as $2.1 billion worth of senior secured notes due in 2027, senior unsecured notes due in 2029, and exchangeable senior notes due in 2027 -- none of which terms investors need to pay close attention to. Just think of them all as debt. The company will use the cash raised from the sale of these notes to roll over debt that it sold previously, such that the net result of all this activity should be...