So. This theory was made by me, If you see when the stern sinks after the breakup, it can’t start sink again so fast, and sink look like it’s being dragged, so i think that when it breaked up the lower part was dragging the stern along with stern, then it’s destroys due to the stern and bow was getting a little farther and farther until it breaks, but the break up was caused by overload and boiler explosion of third or second funnel. May sound very fake, but it’s first time trying to make my theory.
