The nuclear submarines Nautilus and Skate were able to navigate below the what in 1958?

Both boats were the first submarines to navigate under the Arctic ice pack. However, the Skate actually surfaced through the ice, whereas the Nautilus did not.

Under Ice navigation, even with modern Sonar, is not easy because of the constant movement of the Arctic ice pack. Though shipping noise is a lot less because of the location, the constant ice movement produces many cracks, pops, hisses, and other noises that make it difficult to detect a stationary submarine that may be surfaced and running with minimal machinery. Detection ranges are also severely limited.

If you wish to see some pictures of Submarine under-ice surfacings, check my Supervisor bio page - I've added some pics from our historic 1986 mission to the North Pole, taken from a C-130 aircraft flown there to document the event. There were 3 boats in all - my own, the RAY, the Archerfish, and the Hawkbill. We all surfaced within a couple of hundred yards, though the Hawkbill surfaced about 30 yards from RAY.

I was actually promoted to First Class on the ice at the North Pole along with a few others as well, and it says so on my promotion certificate. It was a tough trip - we lost our refrigerant capability about 2 weeks after leaving port, being unable to stop all Freon leaks. Freon when heated changes to deadly Phosgene gas, which is a real problem when you're under the ice and can't surface immediately to snorkel and get rid of toxic air. We lost our freezers and the food in them as well. We put fresh, refrigerated stuff in an empty Torpedo tube, as the water in the Arctic is a constant 28 degrees F. We ate a lot of canned stuff, and I've never been able to eat Ham and Cheese together since it was pretty much all we had. We even chopped ice to keep fresh supplies we got from one of the Ice camps, but it didn't last long. I lost over 60 lbs on that trip, others even more.