Regarding the 'rotation' of the stern section, here's an abbreviated version of Jack Thayer's account of events as seen from his viewpoint in the water, forward and to starboard:
"Long and I had been standing by the starboard rail, about abreast of the second funnel ... I sat on the rail. I faced out, and with a push of my arms and hands, jumped into the water as far out from the ship as I could ... The ship was in front of me, forty yards away ... The water was over the base of the first funnel. The mass of people on board were surging back, always back towards the floating stern ... Suddenly the whole superstructure of the ship appeared to split, well forward to midship, and bow or buckle upwards. The second funnel ... seemed to be lifted off, emitting a cloud of sparks. It looked as if it would fall on top of me. It missed me by twenty or thirty feet. The suction of it drew me down and down, struggling and swimming, practically spent. As I finally came to the surface I put my hand over my head, in order to push away any obstruction. My hand came against something smooth and firm with rounded shape. I looked up, and realized that it was the cork fender of one of the collapsible lifeboats, which was floating in the water bottom side up ... Sitting on my haunches and holding on for dear life, I was again facing the Titanic
There was the gigantic mass, about fifty or sixty yards away. The forward motion had stopped. She was pivoting on a point just abaft of midship. Her stern was gradually rising into the air, seemingly in no hurry, just slowly and deliberately. We could see groups of the almost fifteen hundred people still aboard, clinging in clusters or bunches, like swarming bees; only to fall in masses, pairs or singly, as the great after part of the ship, two hundred and fifty feet of it, rose into the sky, till it reached a sixty-five or seventy degree angle. Here it seemed to pause, and just hung, for what felt like minutes. Gradually she turned her deck away from us, as though to hide from our sight the awful spectacle. Then, with the deadened noise of the bursting of her last few gallant bulkheads, she slid quietly away from us into the sea."
Compare that with The testimony of the Chief Baker, Charles Joughin, who remained on board the stern section right to the end. He described not a rotation in the sense of a change of heading, but rather a great increase in the list to port, sufficient to throw hundreds of people on the well deck off their feet. At that point he was able to maintain his footing only by holding onto the starboard rail and climbing over it to stand on the side of the ship. The greatly increased list to port would of course account for Thayer's observation that the stern "turned her deck away from us".
Quincy, you will be particularly interested in this comment from Thayer: "I afterwards heard from my friend, Richard Norris Williams, that his Father and mine were standing in a group consisting of Mr George D. Widener and his son Harry, together with some others. They were close in under the second funnel, which was very near to where Long and I were". That confirms that your Grandfather was on the starboard side. Thayer's account of the falling second funnel is more of a puzzle. According to Lightoller, it was only the first funnel that came down on the starboard side.
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