[REL] Enable starting XVIII U-Boat in Career

[bell117]

Originally Posted by germancrowd

only because i see this mistake in the whole forum XVIII and XXI is very similiar (bloody romans) thats all

It IS the type XVIII, it's just that the game devs got lazy and re-used the model for the type XXI, that and that the XVIII was a proposed alternative to the XXI, but this thing differs cause of that walter-turbine, and also the lack of batteries, (copper-zinc prototypes)