After Germany declared war, the commander of the German U-boat forces, Admiral Karl Dönitz, a former U-boat man from the First World War, was tasked with drawing up plans for the U-boat offensive on America and Allied interests in the Caribbean.
The Germans had been developing just the boat for the job too, the large Type IXC (see above). It had a much longer range and greater torpedo capacity than the smaller Type VII's that had been battling it out in the North Atlantic. The larger diameter hull allowed for the addition of a second torpedo tube at the stern. It also had a larger main deck gun (105mm vs. 88mm). The main armament was supplemented with a 37mm single shot "quick firing" canon on the aft deck. Both types of U-Boats relied on a single 20mm automatic canon for anti-aircraft defense, and also for suppressive fire for close-in attacks.
As a side effect of its size, the Type IXC's were a bit more tolerable on these longer patrols, although they could never be described as roomy. Both types were designed to provide the best combination of performance and lethality, with little consideration for crew comforts. There is a Type IXC that was captured later in the war, the U-505, which is on display at the Museum of Science and Industry in Chicago. I had the opportunity to take a tour of the boat a couple years ago just after it's remarkable renovation, and let me tell you it's not for the claustrophobic. We had one person leave the tour before it really got started, and they were standing 4 feet away from the large rectangular doorway the museum chopped into the side just forward of the control room to allow easier access. If the Type IXC had a weakness, it would have to be the slower dive rate when compared to the Type VII. This wouldn't really be a factor though in these early operations, since we were so unprepared.
There were really two main reasons for this:
1. Lack of a serious airborne countermeasure. There was a vast area of the Mid-Atlantic cleverly called the "Mid-Atlantic Gap" that was either out of reach of most of the planes of the day, or not patrolled by those that could reach it (see Admiral King below). The Germans were even comfortable enough to hold age-old Navy ceremonies such as the 'crossing the line' ceremony to initiate new sailors who are crossing the equator for the first time. There are some amazing pictures from the granddaughter of one of U-126's crewmen showing just such an event here (along with a collision that took place earlier in her career). Note that the lookouts are still hard at work scanning for targets or danger on the horizon, however.
This would change and change rapidly. The allies were working hard on airborne radar systems that would help them locate the U-boats and new and more effective weapons like compact but powerful depth charges and acoustic air-dropped torpedoes that would home in on an escaping submerged U-boat's propellers. Dedicated hunter-killer groups comprised of destroyers and destroyer escorts with escort aircraft carriers that could launch radar equipped aircraft anywhere in the Atlantic. British cracking of the German enigma codes and Dönitz's obsessive micro-management gave us a general idea of where to hunt. The combination of better intelligence and improved technology was lethal. Before it was all over, aircraft would become as lethal as the destroyers and nearly equal their number of U-boat sinkings.
2. The second reason would be the limitations of the U-boats propulsion system. In the automotive vernacular of today, U-boats were hybrids, although it wasn't because of the Nazi's environmental concerns. They used powerful marine diesel engines while surfaced which gave them a top speed of over 18 knots, plenty to run down Merchant ships plodding along at 10 or 11 knots, although not enough to escape destroyers capable of over 30 knots. This brings us to their electric motors powered by lead-acid batteries. U-boats typically dived to avoid Destroyers as their mission was to stop the flow of supplies. These motors propelled the U-boat underwater, but for a limited amount of time, and at a much reduced performance level, about 7 knots max, but usually between 2-4 knots. This was fine for quietly exiting stage right, but not much use in a chase. Submerging in a U-boat was like running down a dock at top speed and jumping into the water. Everything goes into slow motion after you're in the water. At this stage of the war they would submerge mainly for defensive purposes. Due to the lack of performance, offensively they would only submerge if they were already in position near a convoy or spotted a target moving in their direction in the daytime or under heavily moonlit situations at night.
Both of these issues would have a significant impact on the design and tactics of the U-boats. The Germans were working on new designs such as the Type XXI and Type XXIII with much better underwater performance. These would be the first true submarines, designed from the start to operate primarily while submerged. Lucky for us, they ran out of time and were a case of 'too little, too late'. In the mean-time the Type VII and IX would have to adapt to bridge the gap. The deck guns would go away and more anti-aircraft guns would be added in their place. Schnorchels would be added to allow the Diesel engines to operate under water (at least at periscope depth). Newer, smarter 'fire and forget' torpedoes would be introduced that would home in on acoustic signals, or run pre-set patterns through a convoy increasing the chance of a hit, and allowing the U-boat to retreat before it was detected. There were other surprisingly advanced features that would be introduced by war's end, but at the time of Arkansan's attack it was still pretty basic and not all that different from the First World War.
Unlike the "wolfpack" tactics used on the North Atlantic convoys where multiple U-boats would form a patrol line and fold in on a convoy when contact was made, nearly all of these attacks would be one on one engagements between a solo U-boat and a solo merchant ship. In some cases groups of armed merchant ships would try to provide protection for each other, but it was still a lopsided affair in which the U-boat had the advantage of surprise in a now "target rich" environment.
The first official strike would be against the US East Coast and would be called Operation Paukenschlag (Drumbeat). The five Drumbeat U-boats were U-125, U-123, U-66, U-130 and U-109, which had all left their bases in France by the end of December.
The man responsible for countering this attack was U.S. Admiral Ernest J. King. King was a very controversial figure. He was known to be very intelligent, but abrasive, which caused him to make many enemies. As far as Drumbeat, his detractors blame him for not instituting escorted convoys, not requiring coastal cities to institute blackouts, not utilizing our long range 4 engine patrol aircraft over the Mid Atlantic Gap, and an over reliance on regularly scheduled surface patrols. His supporters say King didn't have the resources, which were committed to other engagements, and that the lack of blackouts were a political issue, brought on by community leaders worried about the impact it would have on tourism. Whatever the reasons, the carnage would happen on King's watch. The U-boats would quickly learn to work around the scheduled patrols, and the brightly lit up coastal cities would back-light the freighters, making them sitting ducks for the U-boats.
January 13th was to be the official start but U-123 sank the first ship, the British steamer Cyclops on the 11th near Nova Scotia. British, Canadian, Norwegian, and Panamanian flagged vessels actually bore the brunt of this first wave. Out of the 23 ships sunk and 2 damaged, only 8 were American flagged ships (although other flagged vessels, especially Panamanian likely had American's aboard and vice versa). The first American flagged ship lost in the operation was the tanker Allan Jackson, sunk on January 18th, 1942 by U-66, commanded by Richard Zapp.
The Drumbeat boats headed home February 6th after running out of torpedoes, ammunition, fuel or all of the above. The operation was a complete military success. They sank 23 ships for a total of 150,510 tons, with the loss of none of their own. This first wave would also cost 839 Allied lives, with many more injured. The loss of people and ships would only get worse in the months ahead, and wave after wave would continue to strike along the coast and even into the Gulf of Mexico by May. Eventually King caught on and started running escorted convoys along the coast in May, cutting down on our losses and finally costing the Germans U-boats and men.
Another wave of 4 U-boats had left France around the same time the Drumbeaters and were in position around key Caribbean ports by mid-February. This was called Operation Neuland, and consisted of U-67, U-156, U-161 and U-502. On the evening of the 15th of February the Germans brought the war to the Caribbean with a brazen near-simultaneous attack on the ports of San Nicholas, Aruba by U-156, Willemstad, Curacao by U-67, the Gulf of Venezuela by U-502, and U-161 would maneuver into the Gulf of Paria and strike at Port of Spain, Trinidad. Before their patrol was done, these 4 boats sank 17 ships (mainly tankers) and damaged another 8 that would be out of commission for weeks or months. Many of the damaged boats would have been lost if they were sunk in deep water, but they were sunk in relatively shallow water, embarrassingly right at their piers.
Once again the allies were caught completely by surprise. Most of our preparations up to that point centered on protecting the Panama Canal from a Japanese carrier attack; one that would never come. The ports were not even blacked out even though attacks had already started to occur on the East Coast. The only mistake the Germans made was not committing more boats to these initial waves. It could have been much, much worse. There were far more targets than the U-boats had torpedoes for. Convoys were not started in the Caribbean until July, too late for Bernard and his shipmates on the Arkansan.
U-boats would continue to attack these areas in successive waves until the fall of 1942 and then sporadically throughout the remainder of the war, just not in such a concerted effort. The last successful attack in the Caribbean was by U-516 on July 6th, 1944 when it sunk the tanker Esso Harrisburg. The last American merchant lost in our waters was the Black Point (the former Nebraskan), torpedoed and sunk on May 5th, 1945 by U-853 off the coast of Rhode Island, just days shy of Germany's surrender. The U-boat was attacked and sunk by depth charges the following day with the loss of all hands.