In a development surely worth extreme bragging rights, Seabourn, the luxury cruise company, has unveiled designs for its first custom submarines, designed to take intrepid travellers deep in to the ocean on an excursion of a lifetime.

The submarines will offer excursions for guests on their new purpose-built expedition ships, Seabourn Venture and her yet-to-be-named sister ship, which will sail to the far corners of the oceans carrying two custom-made U-Boat Worx Cruise Sub 7 subs.

The subs will carry six guests and one pilot, who will guide the journey up to 300 metres beneath the surface to explore sunken wrecks and observe reefs and marine wildlife.

Guests will sit in two clear acrylic spheres flanking the pilot’s station, giving them a view in all directions, as the seats are mounted on rotating platforms.

Underwater video camera systems will record both inside and outside for viewing back on board the ship in its Discovery Center. And as this is a Seabourn sub, the luxury element hasn’t been dismissed – there are leather seats, a Bluetooth stereo system and a crucially – a Champagne chiller so guests can toast their voyage of discovery.