sentences:  Owing to persistent bad weather conditions, part of the stranded crew members and some of the scientists could only be rescued in April 1938.And only on 28 August 1938, could "Yermak" free two of the three ships at 83°4'N and 138°22'E.The third ship, "Sedov", had to be left to drift in its icy prison and was transformed into a scientific polar station.