Troop Ship Sunk??

A student in my WWII class, who lived on the East Coast as a kid during the war, has claimed in class that a German U-boat sunk a U.S. troop ship off the coast, with a loss of life around 3,000. He provided no documentaion save his memory of the event.

Has anyone heard of this? I had not and remain very skeptical. But I have also learned never to say categorically that something did not happen during this mysterious war.

Just after the US joined the war, there were a great deal of U-boat sinkings off the East Coast and (I think) in the Gulf as well, until we wised up and initiated a coastal convoy system and blackouts of coastal cities. The Germans called it 'happy time'.

I don't know of any troopship sinkings but in the context of the time it wouldn't be a bit surprising. I can't answer you for sure, though.

I think you are thinking of the USAT Dorchester, torpedoed and sunk off Newfoundland in February 1943, and famous for the 4 Chaplains who stayed with the trapped, and drowned with them.
The loss of life was lower than the figure you give, but was still substantial.
In addition, the SS Leopoldville was torpedoed and sunk in the English Channel in 1945 with significant loss of life amongst the US troops being ferried to Europe.