Hence Germanic is correct, but German highly unlikely.
Given the history of the British isles, I would also venture that English is more influenced by Old Norse than Old German.
It's probably hard to tell in which of the languages (Norse, German, English) it originated, because there are little sources in that time (talking mid-first millennium here). From what I know German is a little older than Old Norse (700 vs 900).
Regarding "viking boats", I used that as an example for a type of boat, I'm pretty sure it was a common way of building boats at the time - the Romans used similar rudders. The concept would have been known to all people building ships.
See https://en.wiktionary.org/wiki/starboard#Etymology for details.