Regarding Sam's two questions--
1. Was there some particular piece of information that someone knew about but failed to communicate which might have made a difference to the outcome?
No, there was no one "key" to the loss or lack of situational awareness. This question reflects a misunderstanding the situation. It is possible for a bridge team to have all of the facts at hand, but still be unaware. It is how the information is handled and how the decisions are made that is critical.
2. Was there something that happened that caused someone to loose sight of something that they were aware of that contributed to the accident?
As with question #1, there was no single event that triggered the loss of awareness. However, I do believe that
Captain Smith's arrival on the bridge may have been the final major contributing factor. He effectively took the "deck" while leaving Murdoch with the "con." But,
Captain Smith's role was never spelled out. It was just the nature of the supordinate/superior relationship in pre-WW-I British society, especially the quasi-military society of ship's officers.
Loss of situational awareness can be caused by one instantaneous event. But, this is not usually the case. It is more often the slow buildup of events, actions, assumptions, and even standard operating procedures.
Sam will understand if I say that loss of situational awareness is much like to a machine where all of the parts are in tolerance, but all too big. The machine won't work because as a whole it is totally out of the range of tolerance.
Factors leading to the awareness problems in Titanic range from the layout of the bridge to the unofficial rules governing the use of telephones. They range from the usual and customary practice of dead reckoning in 1912 to the time of night. They include the odd lack of discussion about ice between Murdoch and Lightoller. And, we can't forget
Moody's early prediction of ice did not raise the hairs on the back of Lightoller's neck. The passengers sleeping below had their role to play, as did Ismay. The success of the ships Nessmore (twice) and Arizona with ice encounters did not help. Even the procedure for forwarding ice reports and posting them had influence, as did the relationships between captain and officers as mentioned above. So many things came into play. Most were relatively minor. By themselves, they were non-events, non-factors. But, added together, they meant Titanic was doomed to ride over an iceberg.
--David G. Brown