Hallo TF,

On [www.uboat.net] you can search for and see the locations of uboats on a particular day, also those near the US coast.

Our [historisches-marinearchiv.de] does not list any boats attacked attacked/damaged off the US coast 11 July 1942.

If some uboat was attacked on that day and did not return to port, then there would be no war diary (KT for that boat's patrol, and the attack would then be unknown from German sources.

For you to see which uboats operated off the US coast around the date of the attack but did not return home...

Hope this puts you in the right direction to continue your search.

It might help could you tell us more about the attack on July 11, 1942. Who attacked a uboat: airplane, blimp, escort vessel,...? Where did the attack took place?
Perhaps the attack that has your interest is already defined elsewhere as being on a non-sub...

Best regards,
Walter