I always thought running in to the iceberg played a big part in the sinking.
Seriously, wasn’t the steel very poor quality as well? Very low carbon IIRC..??..
Poor rivets also IIRC?
I once heard that if they hadn’t thrown it into reverse, but merely slowed down and turned, that they may have done a better job at avoiding the iceberg. The throwing it in reverse made it jam for a few precious minutes instead of just slowing down first and then going in reverse. I have no idea of that’s true or not.
High sulphur content which made the steel brittle at low temps. Also the rivets were of poor quality even for the time.
There were also some design issues with the watertight bulkheads which contributed.