Oh yeah. They sunl lots of ships on the east coast
They went all of the way into the gulf of Mexico.
According to this rather interesting site, about 175 (!) merchant ships were sunk off the east coast during WW2.
http://www.usmm.org/eastgulf.html#anchor473040
[detailed list]
http://www.usmm.org/shipsunkdamaged.html
[more of a summary list]
Per my very quick read of the site, that 175 number almost *exactly* matches the number sunk in the North Atlantic. (+/- 1 or 2 ships)
I have not sorted the listings into “damaged” versus “sunk”, but you can see the vast majority were sunk.
They would surface early in the war and sink merchant ships with the deck gun using the lights from east coast cities to silouette them.
“Close to the coast?”
The Germans sailed right up into the Chesapeak Bay and up the Patomac River!
VietVet
At the outbreak of war, the navy Department had just a handful of ships and planes to defend the entire coast from Maine to Texas. This small force proved totally inadequate to deal with the U-boat offensive launched against America by German submarines. Over the first seven months of 1942, the Germans sank nearly 400 vessels, including more than thirty-five ships off Florida.
The most dramatic sinking in Florida waters took place the night of April 10, 1942, when U-123 torpedoed the tanker Gulfamerica off Jacksonville Beach.
The resulting fiery explosion was clearly seen onshore and curious crowds gathered to view the ship's destruction and looked on in shock as the German submarine surfaced and fired its deck gun at the tanker.
In response to the Gulfamerica sinking, in which nineteen crew members were lost, Governor Spessard Holland ordered a blackout of lights that could be seen at sea and might silhouette passing ships.
The number of sinkings declined dramatically in the fall of 1942 due to increased escort and anti-submarine patrols by ships and blimps of the U.S. Navy and Coast Guard, as well as by Civil Air Patrol aircraft and private vessels. The continued presence of U-boats in Florida waters was confirmed, however, by the shooting down of an American military blimp by a German submarine in waters off the Florida Keys in July 1943.
German Saboteurs in Florida:
Florida became the scene of a bizarre plot in June 1942 when four saboteurs came ashore from German submarine U-584 near Ponte Vedra Beach. They buried boxes of explosives and other equipment in the dunes for future use. The men then boarded a bus for Jacksonville, before splitting into two groups that traveled to New York and Chicago. The agents were to join with four other saboteurs, who had landed on New York's Long Island, and then planned to bomb key railroads, bridges and factories producing goods for the war. Fortunately, one of the New York band had misgivings about his mission and surrendered them to the FBI.
By June 27 all of the men had been apprehended. A military court later tried the eight Germans and found them guilty of spying. Six of the spies, including all of the Florida group, were executed.