As a North Carolinian, it has always amazed me how closely to US shores that Operation Paukenschlag boats were able to operate. We know how poorly US Atlantic coastal defences were organized, manned and equipped in 1942 but still, the capability of U-boats to operate and attack is (and certainly was) stunning. And we tend to forget that for the first 2/3rds of the War, submarines were really surface torpedo boats that could dive underwater temporaily to approach a victim or, after an attack, to try to avoid defensive action. To travel any distance, to run their only effective means of propulsion (their diesel engines), to charge their batteries and compress air, to provide air for their men, to navigate and fully observe their surroundings, U-boats had to be surfaced.
And if a defensive component had few ships or patrol boats and limited attack aircraft and an offensive force was by necessity required to operate in the open, one the most effective means of assistance for the defense was to have as many patrol and observation resources as possible. I'm sure that no CAP plane bombed and sunk a U-boat, but that doesn't matter. If they hadn't been there for that 18-month period early in the War, there would have been relatively nothing.
But for every U-boat commander who was forced to operate further off-shore, or had to use fuel to move to an area less patrolled by CAP planes, or felt that it wasn't safe to move to the easiest pickings along the shore, the CAP presence was an important -- even vital -- part of the US Atlantic defense which was still being organized.
I would urge that we all look not at the bombs dropped but the everyday contribution made by CAP planes being "eyes in the sky" in important areas where there would have otherwise been no defense. The work of the CAP and the fact that they were there was valuable, the dropping of bombs was not so much.

Bruce Henderson, (coastal) NC, USA