For anyone actually interested in the "fire" theory, it is just that; a fire theory.
We've known of a fire being on Titanic since the survivors testified at both American and British inquiries in 1912. This is not new information.
Furthermore if you really want to blow this 'fire' theory to bits, the fire was in the starboard forward end of Boiler Room 6 (the boiler room nearest the front of the ship).
"But omg if the fire weakened the steel it would have doomed the ship omg omg omg." - typical conspiracy theorist.
The truth of the matter is that the iceberg opened up 6 compartments to the sea:
Forepeak Tank
Hold 1
Hold 2
Hold 3
Boiler Room 6
Boiler Room 5
At the time, Belfast shipping yard had concluded that Titanic could stay afloat with the first 3 or rear 3 compartments flooded, along with any combination of other 2 flooded. After the disaster took place, a naval architect from Belfast who worked on the Titanic did various calculations and concluded that they had actually designed Titanic better than they had thought. He surmised that the ship could stay afloat with the first 4 or rear 4 compartments flooded, or a combination of any 3 center compartments flooded.
As has been discussed above, here are the facts:
Titanic can stay afloat with her first 4 watertight compartments breached
Titanic can stay afloat with her rear 4 watertight compartments breached
Titanic can stay afloat if any 3 central watertight compartments breach.
And now for the doosey:
The iceberg opened up 6 compartments to the sea.
At the time of the incident, Thomas Andrews was well aware of the "she can stay afloat with 3 flooded" saying, BECAUSE HE HELPED DESIGN THE SHIP. From roughly 11:45PM - 12:15PM he toured the damaged compartments and took note of how fast each was flooding, how seriously they were damaged, everything he could note...he noted.
No doubt that once he saw that not only where the first 3 compartments flooding rapidly (14ft of water above the keel in 10 minutes) along with 3 more compartments flooding, he knew the ship was doomed. And thus relayed this information to the Captain.
The fire is null and void in this scenario. "oh but it weakened the steel you see! ha ha! Steel weakened = ship sinking ha ha !" No. Again, floats with 4 compartments flooded, sinks with 5. Iceberg opened 6.
Now here is where the bit with the fire gets interesting.
The stokers had been combatting the fire ever since Titanic arrived in Southampton to take on supplies before passengers boarded, and they had just extinguished the fire mere hours (I believe 6 or so) before the ship collided with the iceberg. To do this, they shifted coal that was not on fire over to the Port Side coal bunker for Boiler Room 6. It was then that they got the fire under control and everything was all well in Boiler Room 6 finally.
BUT! All of that extra weight shifted over to the port side of Boiler Room 6 caused the ship to list (lean) to port (left) by around 2.5 degrees. Passengers had even started to notice by Sunday noon. Surviving passenger Lawrence Beesley noted that as he was at lunch with a group of other passengers they noted that if they looked out the Port windows they could not see the horizon, only the sea. If they looked out of the Starboard (right side) windows they couldn't see the sea, only the sky. This would mean that the ship was listing to the left, but not by a huge margin, as most passenger didn't even notice.
edit, as a user pointed out I am going to add this here as I did in a comment down below "This is all speculation and hypotheticals beyond this point"
What makes this lean to Port important is.....the iceberg strike. The coal had not yet been moved back to starboard at the time of the collision, and so the ship was still listing anywhere from 2-2.5 degrees to Port.
Quartermaster Hitchens later testified that at roughly 11:45PM (5 minutes after the collision) that Captain Smith re-entered the Bridge and noted there was a 5 degree list to starboard (right).
Meaning that the ship went from a 2-2.5 degree list to Port to a 5 degree list to starboard in only 5 minutes.
Why is that initial port list important, you might ask? What would happen if it weren't there, and the ship had struck the iceberg at an even trim. Assuming that the force of the water caused the ship to take on the same degree of downward movement, Titanic would be suffering from a 7-7.5 degree list to starboard in only 5 minutes after hitting the iceberg.
At that severe of a list, lifeboats on both sides of the deck would find it very troublesome to launch, not to mention that they had to be readied yet. On the port side the boats would be practically grinding along the hull as they lowered, where on the starboard side they would be swinging anywhere from 10-15 feet away from the boat deck edge, pretty much guaranteeing that anyone to board a lifeboat would have to have the athleticism of a gymnast or they would simply not be able to enter.
And here is an even scarier scenario. As a ship sinks, its center of mavity is constantly changing. It moves from near the bottom of the ship to up near the top as more water floods in, this is hastened by lists. Which is why if you've ever taken a ship model, or seen videos of ships sinking on youtube they always roll over on one side.
It is now 11:45PM. Everyone on board is aware of a frightening list developing to starboard, but instead of stabilizing at 7-7.5 degrees it gets worse. As the center of mavity rises, the ship continues to roll over to starboard, eventually laying over all the way on its side where it then proceeds to sink beneath the waves at roughly 12:00AM - 12:10AM.
Why is this such a scary scenario? Besides the obvious reasons....the first lifeboat never left Titanic until 12:40-45AM. And the first confirmed wireless signals calling for help left only a few moments later. Captain Smith was not aware that the ship was doomed until 12:15AM - 12:20AM...
To put it shortly, the fire saved Titanic by causing the port list before the collision ever took place. If it had not had been for that fire, Titanic may have very well slipped beneath the waves with a 100% mortality rate, and not a single piece of evidence to suggest that she'd gone down. It would have become a ghost ship, and would likely still remain hidden on the ocean floor to this day.
