On getting go to grid XXXX, & patrol for 24 hrs...
is important to note, that for the entirety of those 24 hours, once you cross that grid line, don't matter if you entered it, on the N, S, E or W side of that grid box...
that you NEED to stay within that area...
Now, if in the process of chasing down a target, that crops up... & you inadvertently dip out of the assigned area... NOTE that ALL, is NOT lost on the time you had accrued prior to dipping out of the zone.
What this means, is... will have to tack on that extra bt of time, yu were outside of it, before the time bell, will gong, signifying that you completed that 24 hours patrol in area bell ringer.
Now... as johnny_bass26, points out... there are some patrols, that will be... bolluxed up on getting that bell to ring... just how many, NOT entirely sure...
With GWX, dunno if the gang, ran through the missions and ensured that all was set to rights there... or not... & if there, was NOT a case of some not allowing things to be set to right... as I seem to recall that there are some things, that no matter what gets done... just won't cooperate... no matter what.
Not saying that this is the case, here... just that I don't know & so... am NOT going to say that could or is the case here...
As johnny, rightly sussed out, renown, is NOT a factor (to the best of My knowledge here, at any rate... know that some mods/mod sets... do have renown assigned for completeing patrol here/24 hrs... or was the case, last I know of.) so.... use what torps/deck gun ammo ya got, sink some targets... which is the main thing here... yeah...
Get a good tonnage racked up & the rest'll sort itself out, in the wash.
Gute jagd, ihr Himmelhunde.!
M. M.