3. שאלה מצוינת: צוללות 'רגילות' - עד עובי של מטר, צוללות ארקטיות - עד עובי של 3 מטר בתגובה להודעה מספר 2
(...) while some submarines in the Arctic have features to help surface through the ice, they still cannot surface through ice that is greater than three meters (nine feet) thick. Submarines that are not ice-strengthened can only surface through ice that is less than one meter (three feet) thick. Submarines must be able to quickly locate leads or thin ice to surface quickly during emergencies, to send messages, or to launch missiles.