So, let me get this straight. The iceberg struck the ship on the side and ripped it open just below the waterline. The iceberg was able to do this only because the hull metal had been weakened by a 1,000 degree fire. The fire had been burning for three weeks straight (presumably at or near 1,000 degrees). That necessarily implies that the external hull metal was sufficiently exposed to this 1,000 degree fire that it was weakened.
Now, I know for a fact that metal is a very good conductor of heat. That means that the external surface of the hull would have been at or near that 1,000 degree temperature if the internal surface was at that temperature. Now, I also know that the external surface of a ship's hull is in direct contact with the surrounding ocean. Now, I also know that the ocean consists mainly of water and that water boils at around 212 degrees F (the salt content of the ocean most likely changed this a little).
Which leads to a question: how come this boat was able to toddle along for three - three! - weeks without anyone noticing a big plume of steam coming off the side that was exposed to this 1,000 degree fire?