A member of my family served on a US vessel (most likely, and possibly an armed merchant vessel) which allegedly fired upon a german(possibly austrian) u-boat about 1,5 days out of Gibraltar towards Genoa. According to a old letter written in 1920(apparently on board the Easter Light(which he referd to as the S/S Eastern Light, but according to wikipedia it was called the USS Eastern Light and decomissioned in 1919) by him, which was the last time he was heard of by any of my family members. According to the letter they were being followed by said u-boat and the US captain ordered the crew to open fire, firing three shots before the u-boat returned fire.

According to the letter this happened on the 27th November 1916, before the US entered the war. The captain feared my relative would tell people the US vessel opened fire first(with him being Norwegian), and consequently accused him of espionage.

Do anyone have any idea what u-boat it might have been that was following them, and maybe what ship he was serving on. The letter is very hard to read, and i could only make out a T in the name of the US vessel. It kinda looked like he wrote the "S/S Tusculum of London" or something along those lines. I'm 100% sure he wrote "S/S" and "of London" but i'm unsure of what he meant by "of London."

I'd think if there really was an exchange of fire on the 27th of November 1916 between a US merchant vessel and a German u-boat it would be logged, but i cant find anything about it online.