Wolfgang - shouldn't it be potum instead of portum? Sounds more like the Pott.
For foreigners: Wolfgang's joke can only be deciphered in its true sense by Germans; navigare meant schiffen = to go by boat in older German, but now only to piss.
Students are used to express their wish for a short leave to the loo politely with the words navigare necesse est, but not with the intention of supporting the Imperial Navy.
McGrath - another version of cows and ducks:
Civile si ergo
Fortibus es in ero
Gnoses mare Thebe trux
Vatis inem
Causan dux.