Kapitan Khlebnikov in Loose Pack Ice
Pack ice is sea ice that formed somewhere else and floated to where it is now, this may have been a few miles away or several hundred miles away. In the summer months as in this picture, the ice may have been recently broken up or has not encountered conditions cold enough to freeze it all together again.
Such loose pack is relatively easy to make a way through as the pieces of ice are generally just pushed out of the way to the side rather than being broken unless they are particularly large.
Photo; © Mike Usher - Pictures from an icebreaker cruise to Eastern Antarctica.