newb looking for the XXI

[dyslexic doggie]

now Im pretty new to the computer gaming world, and please dont bash me for what im about to ask.
how does one go about editing the cgf files to get the type XXI real early in the game,
Ive played the game normaly with only dud torpedoes and fuel usage turned off for a dozen or so missions and I love it. but Im real taken by the idea of the type XXI, just wondering if one of you all could help me out here,
after I get it and get bored with it I will probably go find out how hard I can make the game. but for now I just wanna have fun.
dyslexic doggie.