Some one may don't like its 127mm gun,I know it's a little big,not like 127mmSingleGE it used in GWX.
Radar works.
Notice,radar in my warship mod has fixed to your ship yet(so what you use is FuMO 23 or anything like that,not small u-boat's radar),so you needn't and mustn't choose radar or any other u-boat's equipments in menu.