Empress of Ireand sunk in the St Lawrence river (29th of May 1914). 1,012 people were killed, as the ship went down in just 14 minutes, after colliding with a Norwegian freighter, the SS Sorstad Near Rimouski. 465 of the original 1477 people on board survived.
It seems the story of the Empress has been lost, as it's death-toll was overshadowed by that of the Titanic two years earlier, and the story in international news at the time was pushed aside weeks later by the outbreak of the Great War.
Not to lessen the tragedy of such a wreck, but to ignore it's gaming potential, especially for Call of Cthulhu, would be to deny the reason for this blog's existence. My first thought on this, was to use the Titanic as a starting point. As a more famous wreck, in the same time frame and with a very similar passenger list, it would be foolish not to see what was already out there.
Pelgrane Press's RMS Titanic: The Millionaire’s Special is a one-shot adventure placed on the Titanic (before it sinks obviously), a review of which can be found on RPG.net here, with another review by Pookie here. I do not own this adventure, but I would guess it could be as easily placed on the Empress of Ireland, with a bit of rewriting, as you would still get the same feeling of ship-borne claustrophobia, however, with the sinking of the Empress being a lesser known event, maybe the feeling of fore-boding and imminent sinkage would be lessened.
The other issue with the Empress is that it had left from Quebec, heading for the U.K., meaning it was just over 1 day into it's voyage, not much time to build up a narative, meaning an adventure ending here would have to have a build up in Montreal of Quebec City. The other option is to have the Empress being on a return trp when she sinks. It is here that the lack of general knowledge of the disaster works in the Keeper's favour.
For those that read German, there is also Fantastische Spiele GbR's adventure Titanic Inferno, but it seems this has never been translated into English.
CBC article here (the above image is from that story).
Centennial Commemorations of the disaster here.