Shades over mesh and other small problems

Hi everybody!
Here I am again with my newbie questions. Started modeling, doing ok I think but noticed that I get some wird “shades” on my meshes, mostly when the “smooth” shading is activated. Its not the normals, I pushed the “Recalculate” button, no change and I also tried the “remove doubles” option, no good. I post both the problem screenshot and also an Edir mode one, so the meshe is visible. Got the same after an extrude at the stern of the ship I´m currently modeling and I just can´t figure out why.
Also I´ve noticed that sometimes the Cntrl+Z “Undo” button doesn´t work, don´t know why. Happens from time to time, without no apparent reason and it´s not good! Maybe I disable it without knowing?

    I´d really appreciate any help, specially with the mesh problem, thanks in advance!!

Attachments



Depending on the effect you want, adding an edge-split modifier may help.

Oh! That made a difference for sure! If I only knew it before! I´m afraid that many the shades that still show, are made by me trying to makes things better. Right from the start this could make miracles!! Thanks a lot mate, appreciate it!

  I still got the problem with the Cntrl+Z combo, it won´t work! Loaded " Factory settings" but nothing! Maybe it´s my keyboard??

Problem solved, it was my keyboard, was set to English, don´t know why or how…