Having been a player of SHO, as most referred to it by... can tell you, that a SHO skipper's wolfpacking it, wasn't relegated to them, all being on the same page, year wise... so much... as the ability to wolfpack was.
Could be in a Type II & others in the wolf pack could be rolling with... Type VII's or Type IX's... which as I recall were available... think there was Type XXI & XXIII's, in the workup to them... but... can't swear to that, 100% with any surety... as it was a bit back since then.
Whole basis was. completing objectives, which unlocked a multitude of available plans for getting access to improved U-boats, crew... bunker space... even access to improved torps...
each stage opening up more options for objectives that were further out into the open water's... following the general progression of the war... an almost... SH3 open world experience but 1 in which wolfpacking was the main focus...
If I recall, SHO... closed out, 12/ 2016... as I recall. A shame, as for a browser based set up, it wasn't too terrible of a concept.
I do, however feel... it would have been better served, had Ubi, gone with instead... a launcher-based approach... similar in scope to... say... Star Trek Online or Star Wars The Old Republic... or god forbid My even saying this... but... in a World of Warcraft, manner... but, better in scope as STO or SWTOR.
Hope this info helps... on understanding better about SHO...
from a former SHO player's perspective.