As ship's bow is designed to break the waves, the physics (something like hydrokinetics) makes it should look like a wedge. And it really is, if we look from above. This should be also kept if look from side.
This is a picture of the bow of a modern ship (let's call it a 7-shape):
Wikipedia has also different kinds of bows on this picture, but all are very similiar:
Looking at warships bow during historic eras we can notice that shapes have changed.
This trireme bow was designed to operate as a ram and destroy enemy's ships.
A caravel was not intended to touch other ships, so her bow is physically correct:
HMS Africa, which fought in the Battle of Trafalgar, had "normal" bow too:
But in 19th century and early 20th the ships bow was again looking like the one of the trireme, but more C-shaped, having keel longer than the deck:
German postcard comparing losses during the Battle of Jutland:
I think however it is not as long as in ancient galleys.
The RMS Titanic did not have a ram, as she was a civilian ship:
Then again, in WW2 and later, we go back to "correct" 7-shape, for example:
Modern USS Bainbridge:
And my question is:
What was the reason of C-shaped bows in 19th century and WW1? Was it the same as a ram in ancient galleys? Why did everybody expect to ram enemy's ship? Were there any successful attempts in the age of heavy naval artillery?