There's always more to be said, I guess, but you may be interested in my earlier answer to What was the popular view of the RMS Titanic between its loss in 1912 and discovery in 1985? At the end I briefly discuss conspiracy theories:

As far as conspiracy theories go ... there are a few alternative ideas as to how the sinking went, largely late-twentieth-century and largely just about technical details. The real conspiracy theory is the one put forth by Robin Gardiner just a few years ago stating that the boat that sank was actually the Olympic, a sister ship that resembled the Titanic and had been somewhat damaged a year earlier, and that the Olympic that sailed after the "Titanic" went down for the insurance money was actually the Titanic. There don't seem to have been any widespread conspiracy theories in the early twentieth century that would be comparable to "jet fuel can't melt steel beams", perhaps because the details were so thoroughly hashed out at the time.