On the sort of site which doesn't deal with real climate science, much is made of the idea of 'open water' in the Arctic. The suggestion is that open water is not an unusual occurrence. That is true, but it must be remembered that the term 'open water' is ambiguous: it is entirely indifferent to area. The term 'open water' is applicable equally to a small polynya or the great expanses of open ocean seen in this, the 21st century.
The Arctic ice has always been mobile and so has always had some amount of open water within the main pack. Pushed first this way and then that by strong variable winds, continuous ice tends to form cracks called leads. These can be just wide enough for a kayak or wide enough for a very large ship. A lead can stretch for a few meters or for many kilometers. In winter, leads and polynyas are likely to freeze at the surface.
Almost any report of Arctic exploration will make reference to 'open water' at some stage. In a region where close-packed thick ice is everyday fare, it is only the extremely unusual discovery of a fairly large stretch of open water that is worth reporting. Unless, perhaps, the explorer is in a submarine, in which case even the tiniest amount of open water is of interest. In his book "Surface at the Pole", Commander James Calvert, USN remarked of the 5th polyna found in 1959:
I could see through the periscope two small black spots on the underside of the thin ice. Suddenly I could make out ripples in them. It was the first open water we had seen on the cruise. The puddles, about 2 feet in diameter, showed that the ice in this lead must be very new.That 'open water' was found in March 1959, about 100 miles from the New Siberian Islands, a few days after surfacing at the pole. Previously, having found no open water, the USS Skate had surfaced at the pole through a frozen lead on March 17th. The ice was so thick that it did not obstruct the conning tower with fragments as previous thinner ice had done. Not only was the ice thick, but it was hummocked to a height estimated at 18 feet, "... the tallest we had yet seen in the Arctic."
USS Skate surfaced at the pole, March 17 1959.
Source: Surface at the Pole, Commander James Calvert, USN, pub:Hutchinson, 1961
These pictures were taken in Arctic twilight, two days before polar dawn. Thick ice covers the after deck in the top image. The lower picture was taken in the light of flares, such as the one held by the crewman, third from left foreground. The three men on the foredeck are ready to fire a salute following a brief memorial ceremony and the scattering of the ashes of Sir George Hubert Wilkins, MC and Bar.
In the days of wooden ships, the tactic of Arctic explorers was to make for a previous 'furthest north' and then hope to find that local weather variability had produced conditions suited to further progress. It is very common to find reports of open water where previous explorers had found solid ice. It is also very common to find that any report of open water is swiftly followed by a report of solid ice, or even of the ship being trapped in the ice.