The word enormity refers to something strikingly awful, such as a grave social transgression or an act of great moral evil. It does not refer to great physical size.
The Titanic was an enormous ship. It was not a ship of great enormity. It's quite possible that some gentleman traveling first class on that ship came down to dine with mismatching cuff links, thereby committing a social enormity. (That poor fellow probably felt like drowning himself.)
Were I but King of Anglophonia
Oh, the Enormity!