The theme of the excerpt is overcoming obstacles and difficulties. The author establishes the need to be brave and courageous despite sadness and despair. At the beginning of the fragment the author states the challenging and painful situation the group has to face as well as the slight chances of survival of the pilot whale. This description makes them feel frustrated and sad about the apparent inevitable consequences. Despite this, as the passages continue, Mr. Manning encourages the group to stay calm, to be positive and work hard to overcome this appalling situation.
The answer is when his wife asked for him to wish her four pairs of hands in this excerpt, they didn't believe that the story they were told was true, so she was mainly making fun of the major's warning.