The Britannic was the sister ship to the Titanic.
And, like her unsinkable sister ship, the unsinkable Britannic sank as well.
Oh, sure, their reinforced the Britannica’s hull. And added more life boats.
And the Britannic spent her life as a hospital ship in warmer waters than Titanic.
But where the Titanic’s spotters failed to spot an iceberg, the Britannic’s spotters failed to notice a mine.
Which is understandable, since mines are much smaller than icebergs.
And make for less interesting movies, I suppose.
The third sister ship, Olympic, was sold for scrap and demolished.
Even less interesting, I suppose.