Out of curiosity, I tried Googling "alt Somerstadt" and saw an article about a Norwegian ship "Somerstadt" struck by a torpedo... I don't know more about it, and only pursued it far enough to get the link which contains a poor OCR version of the document and may not offer much additional information -- here is the paragraph I found inside (poor OCR and all)"
TORPEDO TURNS TO STRIKE
The case of the Norwegian steamer
Somerstadt, which was sunk on August
12th ofT Fire Island by a recurving tor¬
pedo, as stated in the official report, has
raised the question among experts as to
whether the Germans have not utilized the
American invention of radio or wireless-
directed missiles of that character.
While there is nothing in the official re¬
port to indicate that the torpedo whitffi
destroyed the steamer took its eccentric
course of passing the bow and returning
to strike fatally on the port side by the use
of radio power, it is not denied that such
might be the case.
Anyway, it occurred to me that your ancestor might have been aboard this steamer, hopefully prior to the torpedo incident. The document itself was written in 1919, so the incident must have happened before that.