This is a massively detailed CG model of the German Type II submarine. THe hull is split horizontally along the long axis of the boat, offering superb access to the interior. The layout is optimized for RC implementation. 
 
The largest part is 188mm along the longest axis, making most printers capable of printing it without modification. Overall length of the boat, once assembled, is 141cm (55.5"). Hull opening for a cylinder is 86mm wide. 
 
NOTE: These files were created in cm, meaning most slicing programs will require scaling the parts up by 1000% to get the correct dimensions in mm.