North Pole Since 2002, the Russians have also annually established a base, Barneo, close to the Pole. This operates for a few weeks during early spring. Studies in the 2000s predicted that the North Pole may become seasonally ice-free because of Arctic ice shrinkage, with timescales varying from 2016 to the late 21st century or later. The sea depth at the North Pole has been measured at by the Russian Mir submersible in 2007 and at 4,087 m (13,410 ft) by USS "Nautilus" in 1958. The nearest land is usually said to be Kaffeklubben Island, off the northern coast of Greenland about
Skipjack-class submarine planes were moved to the massive sail to cut down on flow-induced noise near the bow sonar arrays. They were known as sail planes or fairwater planes. The "Skipjack"s were the first class built with sail planes; they were later backfitted on the "Barbel"s. This design feature would be repeated on all U.S. nuclear submarines until the improved , the first of which was launched in 1988. The small "turtleback" behind the sail was the exhaust piping of the auxiliary diesel generator. The "Skipjack"s also introduced the S5W reactor to U.S. nuclear submarines. It was known as ASFR (Advanced Submarine