Titanic will forever be a monument-reminder to designers to never be too arrogant.
Also in training your crew properly concerning their ship and damage control.
1: even with the undersized rudder they probably would have dodged if they hadn't given throttle orders that deprived the rudder of all turning authority.
2: the form of damage incurred is easily ameliorated with simple shoring components that were readily available; you don't have to stop all the leaking, just obstructing most of it so the pumps can keep up is enough.
