>>but i haven't seen the sites in ages so i'm most likely wrong<<
I'm sure you read it, but just because somebody wrote it doesn't mean they're right. Like Titanic, a lot of myths have grown up out of the affair which have been passed off as history so one has to be careful in fact checking the source material.
>>I am still in doubt over whether the Lusitania's boiler was caused by cold water or ammunition,<<
Since the torpedo hit in the forward machinary spaces while the cargo holds...which is where any ammunition would be...are observably undamaged, I'd say that ruling out ammunition as a cause is about one of the safest bets going.
And if I may, what actual evidence is there that any of the boilers on the Empress of Ireland exploded? Claims are one thing, physical evidence is quite another and the machinary spaces *have* been probed by ROV's. As far as I know, no boilers with burst casings have been found. They may have missed something or something might be out there but not published so if anyone has a photo identifiably from the Empress which supports this, I'd love to see it. (Assuming of course that one has the legal right to post it!)