Sorry for the delay. Notifications apparently are not working for me and Angela has been offline with some medical issues.
In digging a little deeper into this matter, I went and found the name Wilhelmshaven, which is a town in Germany. I found a number of listings for American pronunciation of this word, and it sounds like vil·helmz·haa·fn. According to RUEB, 2nd Edition, 2013, ForeignLanguage, Rule 13.2.3: Use UEB contrcations in words, phrases, proper names and personal titles which are regarded as anglicised. However, do not use a contraction that would unduly distort the pronunciation or structure of a word. This rule seems to contradict itself, so I would be inclined to use the contraction. Of course there is always, "when in doubt, don't contract." I suppose if I was brailling this for a student, the student would understand the word either way: with the "sh" contracted or left uncontracted. Not sure if this is helpful to you or not.