Hey, mate!
I dont think that german subs like 212 were ever created to dive such depths...so 700m are quite a lot! 212 is not a deep sea sub...it was produced for shallow water operations like shoreregions or the baltic sea.
Wikipedia is not the best source to get information about secret stuff like submarines
About the Sachsen: On point is that 3D-Models arent that necessary because you dont have to see it - you have to hear it
3D-models are for cosmetic purpose only! And I know how hard it is to design out these models and to give them good looking textures... :/
Sorry for that buddy, but there are many more significant aspects to be solved first...
My desire to fix a multi-station bug with the towed array audio was also not accomplished yet, because the general preferences are (unfortunately for my sonar operator) just different...
liebe grüße
panzermensch