On 15 July, "Thornback" sighted submarine , and the two boats exchanged information on their hunting areas. They also swapped movies, precious commodities for boosting morale on board the crowded boats. Six days later, "Thornback" proceeded north to patrol off Erimo Seki, an area which had recently seen a series of devastating carrier raids by Admiral William F. Halsey's Fast Carrier Task Force 38. The submarine's commanding officer noted somewhat humorously, "This area should be about as heavily traveled as the Sahara Desert after the working over it just had..."