This is World War One correspondence between the naval command at Wilhelmshaven and the commander of the Santa Cruz docked at Emden. I understand some of the cover but not all of it. I'd appreciate help interpreting and characterizing this. I can't read all of the script (handwriting). Thankfully this style of writing has fallen out of use.
Its a turned cover. I do not understand the boxed rubber stamp on the return side of the cover. I can't identify shiftpost no. 170. I suspect it's connected to the Santa Cruz. I cannot find a reference to the SMH Santa Cruz, though I turn up a similarly named ship built later and used in World War Two. Any observation will help.
Looks like internal business correspondence. The handwriting is pretty clear, no Sütterlin as could be expected. The rectangular stamp probably is a mark to register incoming mail, as is still customary in businesses.
S.M S. Stands for Seine Majestät Schiff (his majesty's ship/vessel). It was manually changed to S.M.H. which means Seine Majestät Hilfsschiff. So the Santa Cruz was an auxilliary ship. So far no information has come up when this is entered in Google.
Im Gegensatz zu den sogenannten Express- oder Postdampfern der Cap-Klasse wurden die nach 1900 gelieferten Frachtschiffe für die Hauptlinie als Santa-Klasse bezeichnet, da bei 15 der 16 bis 1914 gelieferten Schiffen der Namen mit Santa begann. Aber wie bei den Cap-Dampfern gab es auch bei den Santa-Dampfern verschiedene Gruppen. Die Schiffe die nur Fracht oder auch Zwischendeckspassagiere befördern konnten, wurde in fünf Gruppen von zwei bis fünf Schiffen geliefert.
So there were in total 16 ships whos name began with "SANTA"