Technically, if Ismay "fired" Captain Smith he had several more "captains" standing in the wings. Most of the ship's officers were legally qualified to take command. However, if Ismay's motivation was to require the master to do something unsafe...and E.J. Smith refused...the other licensed officers would have had to do the same thing. Dangerous is dangerous. I seriously doubt that Wilde, Murdoch, Lightoller, etc. would have accepted command upon the condition that their first order be to place the vessel in jeopardy.
From a practical standpoint, once a ship sails it is the captain's personal vessel. Even in 1912 the courts would have favored the captain's responsibilities over the rights of the owners -- provided that the captain was behaving in a prudent manner and conducting the voyage to its intended destination.
I must disagree that Ismay wanted the slow the Titanic. It is quite obvious that Ismay wanted a faster voyage than Olympic's maiden crossing. And, Ismay admitted during the U.S. hearings that some sort of speed "stunt" (my word) was planned for the Monday that never dawned. On the night of the accident, Titanic was actually consuming coal at a faster rate than her bunkers could have sustained for a full 7 days. Fortunately, the first part of the trip was slower and there was barely enough coal for a safe passage.
Captain Smith handed that famous Marconigram from the Baltic regarding the ship Deutschland to Ismay because it pointed out the folly of burning more coal than the bunkers contained. The Deutschland was out of coal...a drifting derelict...and as such was a menace to navigation. In effect, Smith used that Marconigram to tell Ismay that he was not going to get a high speed trip all the way to New York. Historians have mistaken the Baltic memo as an ice warning because it mentioned some ice. However, the real message was about a drifting ship where none ought to be.
Smith did not "leave the bridge" while the ship was in the ice. That is another distortion resulting from landlubber historians. (Not to offend anyone, but most books about the ship contain huge mistakes regarding the way ships operate.) Boxhall was very specific that the captain remained in the "rough square" formed by the chart room, forebridge, and the captain's private navigation room the whole evening. And, Smith was on the bridge during the final moments of the accident--this confirmed by Olliver and Boxhall. It is a myth that he was "off duty" in his cabin. He was very much part of the management of Titanic after about 9:45 p.m. that night.
The captain's job is not to take over every detail of conning the ship. Rather, he is to oversee the performance of his officers and crew. A good captain does not sit like a vulture on the bridge waiting to pounce on a bad decision. He gives his men some "breathing room," but stays in contact with events. A captain needs to have some distance from the minute-by-minute operations in order to make judgements of a more global nature.
Smith's actions throughout the evening were those of a prudent captain. He came on the bridge just as Lightoller was ending his watch. This was also the hour when the ship was expecting to enter the ice zone. Smith questioned Lightoller about the sitution...and then held a similar discussion with Murdoch. This ensured continuity of command across the change of watch. It also brought Captain Smith "up to speed" on the general situation.
Later, Smith did his own plotting of Lightoller's 7:30 p.m. star sights. This is unusual for a captain. Normally, that work would have been done by one of the officers and checked by the captain. However, Smith did it himself. This indicates that he had some concern over the ship's position, probably relative to the ice (and maybe to Deutschland).
Smiths famous instruction to, "Call me if it becomes doubtful," is a classic captainspeak. He was reminding everyone that he was the captain and they were to keep him advised. It was not necessarily the statement of a man on his way to bed. He would have said the same thing if he were going inside the chart room for several minutes. (I've used a similar phrase when leaving the wheelhouse for the necessary room.)
Regarding Ismay's "breakdown" aboard Carpathia
. Maybe it happened, but I'm not convinced. Ismay could not have walked out of that cabin without risk of being attacked by several hundred newly-made widows. To the survivors, he was "Mr. White Star."
Beyond that, Lightoller admitted both in testimony and in his autobiography that he and Ismay concocted plans to get the surviving crew out of the United States before they could be questioned. What else went on in that room? Is that where the officers came up with the story that the ship sank intact? What about those coded Marconigrams? Oh, to be a fly on the bulkhead of that cabin.
Mail ships held contracts to carry the mails. To earn those contracts they had to be able to maintain certain minimum speeds. Need I say more?
--David G. Brown