Despite searching the internet for quite some time I haven't found answer (forgive me if this has been asked before). I've noticed on some type IXC/40s that the upper/deck bow section tapers in and then out, starting at the water inlets and ending at just before where the railings start. A good example is U-190, but I've also seen it on others and schematics for the type IXD2. Any info as to what it is, and why some boats have this feature while others do not?