It is very unlikely that anyone reading this site takes the myth of the Bermuda Triangle seriously. MAC cannot count the times he’s received messages along the lines of “If it’s a myth why are all seafarers scared of it?”, to which the answer is that they are not.
Nevertheless there are interesting cases, one of which is the US navy’s Proteus Class colliers of which four were built and three lost in unknown circumstances, two of them in that rather loosely described area known as the Bermuda Triangle.
Chief among the case is the USS Cyclops and the USS Nereus, which vanished while still owned by the US Navy while the Proteus, from which the class drew its name, vanishing after decommissioning and being sold off. Nazi U-Boats are widely presumed to have been involved but that is not supported by records. So what could have happened to them?
Two keywords: Liquefaction and free surface effect.