I find it remarkable now (given the current state of the Arctic sea ice) that the ice was so thick back in the summer of 1975. Regarded as the worst years for many decades from an Arctic navigation point of view. I can't believe this has changed so much in my lifetime.
I came across this account of the navigation difficulties encountered by the Foss tugs endeavouring to make it to Prudhoe Bay.
http://www.mxak.org/community/jeffrey_foss/Pages%20from%20TowBitts_April2013.pdfThe ice at Point Barrow did not yield as 'normal' in early August. It wasn't until Sept 2nd before the first lead opened to allow tugs navigate through the pack ice. It took 2 days to work through the 165 miles of ice clogged waters and make it to Prudhoe.
But all through September the ice never relented and by Sept 28, 6 inches of new ice had formed. They needed the assistance form the coast guard ice breaker to make it through.