When the Crystal Serenity, a 1,000-passenger luxury liner, sails in August on a monthlong Arctic cruise through the Northwest Passage, it will have a far more utilitarian escort: a British supply ship.

The Ernest Shackleton, which normally resupplies scientific bases in Antarctica, will help with the logistics of shore excursions along the route from Alaska to New York through Canada’s Arctic Archipelago.

But the escort ship will also be there should the Serenity become stuck in ice or if something else goes wrong. The Shackleton can maneuver through ice and will be carrying emergency water and rations for the liner’s passengers and 600 crew members, gear for containing oil spills and a couple of helicopters.