I went through the whole Speaking With Silence quest in finding Karliah, and then went to the Skyrim wiki about it and read that the model ship, one of the larcency targets, was in the cave. I knew I hadn't picked it up (and checked just to be sure) and then went back to find it. I watched a Youtube video so that I knew the exact location, went to the room, and it wasn't there. On my first trip through the cave, I had gone to the same room, and was confused by it since the pillar thing was there with nothing on it. When I first went in the room, no oil was on the floor, the lamps weren't hanging above it, and the ship wasn't there (I also highly doubt that Mercer went in there and somehow set it off himself)...I'm guessing this is a bug. Do I need to redo the whole entire cave from the beginning so that I can get the ship?