My knowledge of hydrodynamics is a bit sketchier than aerodynamics.
That being said. Several years ago I saw a large scale model of RMS Titanic at the National Geographic Explorers Hall several years back.
My first thought on seeing how small the rudder was in relation to the hull, was that it was about 1/4th what I expected.
It may not have been the cause of the sinking, but my gut tells me that it didn't help a lick.
The "wrong way turn" thing seems unlikely to me, but I don't have a dog in this fight either way.