The fire aboard was something that was known about after the event and it is even mentioned at the original inquires held in New York and in England as survivors gave evidence. Only the passengers weren't told during the trip about a fire onboard
I'd recommend watching the programme as a lot...
I think that it was said in the programme that they would probably have run out of coal if they had slowed for the ice and then sped up again (the country had a coal strike and the Titanic only took on just enough to make the trip - The original coal bunker fire could have been burning for...
Watch the documentary if you can, it covers things like the coal strike meaning that they only just had enough coal on board and had they slowed for the ice flows that they would have probably run out of fuel and failed to make their maiden voyage unaided through to the effects of the fire and...
Which is why the authorities probably chose to basically ignore the fire when carrying out the public inquiry into the disaster.
Was that national pride / fear of the damage it would have on the British reputation, etc..., political pressure or simply something like bribery by those involved to...
If you haven't already seen this documentary, it's well worth a watch (only available for another 17 days)
http://www.channel4.com/programmes/titanic-the-new-evidence/on-demand/64665-001