Well, to each his/her own.
I do "cheat"... when it comes to renown. The way the game assigns it is, imho, bullocks. As far as I know, and I may be wrong on that, GWX does not assigns renown for time at sea, patrols completed, assigned area patrolled, etc . Only tonnage counts.
Which sucks if you play by certain house rules, such as no attacks in heavy sea states, or you transfer to another flotilla that uses a different type of u-boat, and you can't afford the type that is used in the flotilla because.. well.. you did not sink enough ships.
Don't get me wrong, I love GWX... but the renown is unfortunately the currency of the game. I think we are getting a bit short changed.