Very good question Goosegrl and very interesting research sought. Though you have much of it down you must know that the bow of the ship was lighter than the stern in weight measurements. The ship did break at the 3/4 mark when the balk heads had become filled up and the ship started going under. The ship then started the process of the stern to rise and with this, it broke in "half". It would be impossible for a ship to break under the surface. The air in the bow of the ship began to release and made the bobbing of the front of the ship short, as you said. But like I said the stern of the ship was made to be heavier because of the bouancy and the displacement of the water when the ship settled in the water. I hope this information ahs helped you in a great way and if any more questions feel free to ask, I know many of us on here have our own theories of the sinking of this great vessel. Have a good day and hope this helped you.

NYMedic130