Agent Issues Passport Online reports big growth in cruise tool By Kate Rice / March 08, 2013 Share 1 -- Passport Online reported that its Tandem cruise booking engine had a 200% year-over-year growth in bookings in January and February.The company said the number of agency users has doubled in the past year.Passport Online introduced Tandem in 2011. It is the preferred cruise booking platform for the American Express Travel Representative Network, Ensemble Travel Group and dozens of individual agencies. Tandem integrates marketing, shopping and booking capabilities. Agents have the option of using a booking engine for consumers on their websites.Passport enhanced Tandem's functionality last year, adding the ability to book Allianz trip insurance within the booking path. Passport Online also added Tandem to Trams Live Connect, allowing agents to move customer profile data into the cruise booking process from ClientBase and back.Tandem currently sells 12 cruise lines and supports preferred-supplier preferencing.Follow Kate Rice on Twitter @krtravelweekly.