Highly recommend this book, points out the extremely poor initial response of the US Atlantic fleet to the U-boat threat. The sub commanders stayed offshore during the day and then snuck up close to cities like NY to see targets silhouetted by the bright city lights, we didn't believe in blackouts.
Torpedo Junction: U-Boat War Off America's East Coast, 1942 (Bluejacket Books)
If lines were to be drawn on a map from Cape Race, Newfoundland, down the east coast of the North American continent and into the Gulf of Mexico and the Caribbean, they would coincide with perhaps the most congested sea lanes in the world. When the United States entered World War II, the industrial cities of the eastern seaboard were particularly vulnerable to the disruption of these lanes. Fuel was required to keep those cities from freezing during the winter, and most of that fuel was provided by ships hauling it from Curaçao and Aruba in the Netherlands West Indies, from Venezuelan oil fields, and from the Gulf of Mexico ports of Corpus Christi, Houston, and Port Arthur, Texas. The United States military was also vulnerable. The oil reserves of the United States were simply not large enough to meet the sustained, high demands of world conflict. To cut her supply lines along the Atlantic coast and to the south would be, in effect, to defeat the United States, to freeze much of her population, and force her out of the war. In January 1942, five German Type IX U-boats set forth to accomplish all that.
Torpedo Junction: U-Boat War Off America's East Coast, 1942 (Bluejacket Books)
If lines were to be drawn on a map from Cape Race, Newfoundland, down the east coast of the North American continent and into the Gulf of Mexico and the Caribbean, they would coincide with perhaps the most congested sea lanes in the world. When the United States entered World War II, the industrial cities of the eastern seaboard were particularly vulnerable to the disruption of these lanes. Fuel was required to keep those cities from freezing during the winter, and most of that fuel was provided by ships hauling it from Curaçao and Aruba in the Netherlands West Indies, from Venezuelan oil fields, and from the Gulf of Mexico ports of Corpus Christi, Houston, and Port Arthur, Texas. The United States military was also vulnerable. The oil reserves of the United States were simply not large enough to meet the sustained, high demands of world conflict. To cut her supply lines along the Atlantic coast and to the south would be, in effect, to defeat the United States, to freeze much of her population, and force her out of the war. In January 1942, five German Type IX U-boats set forth to accomplish all that.
