Ludwig made a practice of visiting docks in New York Harbor and along the New Jersey coast where, from his observations, he could report information to Germany on the identities of the ships and their cargoes. He also visited various U.S. Army posts, and reported on the identities of the individual units of each, as well as their organization and equipment which he felt would be of interest to his superiors. By December, Ludwig had also included information regarding aircraft manufacturing and performance based on his surveillance of aircraft plants in the Long Island area (notably Grumman, to which he assigned the code name "Grace").