They were modern adventure travelers, following the doomed route of Sir Ernest Shackleton to the frozen ends of the earth. They paid $7,000 to $16,000 to cruise on a ship that had proudly plowed the Antarctic for 40 years.

But sometime early yesterday, the Explorer, fondly known in the maritime world as “the little red ship,” quietly struck ice.

There were the alarms, then the captain’s voice on the public address system calling the 100 passengers and the crew of about 50 to the lecture hall, according to passengers’ accounts on the radio and others relayed from rescuers and the tour operator.

Image The cruise ship Explorer seen from the National Geographic Endeavour, a small research vessel that was nearby. Credit... Michael S. Nolan/Lindblad Expeditions Inc.

In the lecture hall, they were told that water was creeping in through a fist-size hole punched into the ship’s starboard. As it flooded the grinding engine room, the power failed. The ship ceased responding.