The cruise, organized by the Flat Earth International Conference, promises to be a lovely time. Flat earthers – who include the rapper B.o.B. and reality television person Tila Tequila – will be able to enjoy restaurants, swimming pools and perhaps even an artificial surf wave.

There’s just one problem for those seeking to celebrate the flatness of the Earth. The navigational systems cruise ships, and other vessels, use rely on the fact that the Earth is not flat: theoretically puncturing the beliefs of the flat Earth crowd.

“Ships navigate based on the principle that the Earth is round,” said Henk Keijer, a former cruise ship captain who sailed all over the globe during a 23-year career.

“Nautical charts are designed with that in mind: that the Earth is round.”