Prior to America's official entry into World War II, the U.S. Navy was involved in "short of war" operations against Nazi Germany. In some cases this involved escorting merchant ships that were steaming to help supply England.
Tensions between the U.S and Germany increased after a Nazi submarine fired on the destroyer USS Greer (DD 145).
But, as Samuel Eliot Morison pointed out in the "Battle of the Atlantic," the U.S. was still operating under neutrality legislation. So, when they did stuff to Nazi vessels, they needed to have some legal grounds outside of a war declaration.
On Nov. 6, 1941, the light cruiser USS Omaha (CL 4) and the destroyer USS Somers (DD 381) were on patrol in the South Atlantic looking for a German raider. Two months had passed since the Greer had been fired on, and since then, the destroyer Kearny (DD 432) had been torpedoed and the destroyer USS Reuben James (DD 245) had been sunk.
The Omaha and Somers then came across a ship claiming to be an American merchant vessel out of Philadelphia. The interaction with the vessel drew suspicions, and the Omaha, under the command of Capt. Theodore E. Chandler, ordered the vessel to stop. A boarding party came aboard just as scuttling charges went off. The boarding party kept the ship from sinking, and determined its true identity as the German blockade runner Odenwald.
The ship was taken to Puerto Rico, where the cargo – over 6,200 tons, including 103 truck tires and lots of rubber – and the vessel were sold off. According to Samuel Eliot Morison, the Navy justified the intercept by claiming that the Odenwald was a suspected slave trader.
In 1947, the Odenwald's owners sued the Navy over the seizure. It didn't pan out for them at all. The boarding party and prize crew assigned to the vessel, though, made out big-time: $3,000 each. Crew on board the Omaha and Somers got two months of pay and allowances.
That's a prize worth as much as $34,000 today.
Chandler, though, never got that bonus. Although he was promoted to rear admiral, in January 1945, his flagship, the heavy cruiser USS Louisville (CA 28), was hit by kamikazes off Iwo Jima. While assisting in fighting fires, his lungs were badly injured, and he died of his wounds soon after.