While wandering around in a bookstore a couple of days ago, I ran across and bought "HITLER'S GREY WOLVES - U-Boats in the Indian Ocean" by Lawrence Paterson. It appears that Hitler had sent right at 40 U-Boats to the Indian Ocean in 1943. And from there, a few actually made their way to the Pacific. This was the very first time that I have heard about this operation and plan to make this book my first read of 2018.
Review of Hitler's Grey Wolves: U-Boats in the Indian Ocean