This is off the Bermuda Triangle, where 16+ ships washed up on a sand bar. The mystery is still unsolved. Actually the mystery of the Bermuda Triangle has been given a scientific explanation: methane vents which have been discovered in that region.
Methane reduces the density of water, causing ships that would normally float, to instead sink.
Methane, when in gas form, messes with the electrical components of aircraft, causing them to fail and sometimes fall right out of the sky.
Methane also causes the water to turn a ghostly greenish color, and the “ghost ships” reported to be seen are simply green reflections of the ships that scatter the bottom of the triangle.