Believe it or not that is probably why it sank. The fire itself may bnot have sunk it. Improper firefighting can easily sink a ship. Water is ineffective on open fires of that type. It can be used in enclosed areas in some conditions.
Let me be the first to advance the ever popular theme that the fire should have been put out with an ATOMIC BOMB! There’s nothing that can’t be fixed with an ATOMIC BOMB! Just ask the Russians...
I was pinging UCANSEE2 to this thread. What I linked and blockquoted was UCANSEE2's response to me, when I said the rig may have been lost on account of firefighting efforts.

"As firefighters on shore and in fire boats poured water on the blaze, the ship developed a dangerous list to port due to water pumped into the seaward side by fireboats. About 2:45am on February 10, Lafayette capsized, nearly crushing a fire boat."
http://en.wikipedia.org/wiki/SS_Normandie