The Titanic H&G team have released what I believe is their final demo before Steam release of 'Project 401', which is their walkable Titanic model. It's in Unreal 4 and really is quite fantastic - now 50% of the vessel is modeled.
https://www.youtube.com/watch?v=TOogM9SagAY&t=961s
The Britannic is less famous, but equally sunk.