Here is a video on youtube which describes in good detail how the bow rose up.
The theory defies several things:
1.) The principles of buoyancy.
2.) MOST eyewitness testimony.
3.) What we know about the timeline of those who left the ship (because there were still lifeboats being lowered at the point in which this could even be remotely plausible).
4.) What we ascertain from the wreckage itself.
BUOYANCY:
Once the bow has submerged, even a breach in the amidship hull would not cause it to rise out of the water. It would simply go down even faster. The time frame and the rate of Titanic's sinking excludes such a scenario.
EYEWITNESSES:
While a small handful of people said that the bow rose up, most did not. Even most of those who testified to the ship breaking apart did not see the bow rise.
When it comes to the eyewitnesses, there was obviously some conflicting recollections of the sinking. However, we need to remember that VANTAGE is very important in this. Why?
Someone in a lifeboat or in the water is viewing the sinking from sea level. Some lifeboats are on the port and some of them are on the starboard side. Some lifeboats went forward and some went aft. Most were not far enough away to see the entire ship. Many people in the lifeboats are not looking back at the ship (because of the positioning of the seats). Some would turn look, turn back and then turn and look again. It is very plausible that wreckage and debris might look like the ship.
Someone still on the boat itself is at a particular spot on the boat. They do not see the "big picture" of the sinking. As the ship listed to port, the starboard side would seem to rise up out of the water. Thus, those in the water might have "seen" Titanic rise.
Don't forget that many people were in something of a shock and "fog of war" trauma. Others may have had their "recollection" influenced by what others had seen. The questionable reliability of eyewitnesses is better understood in certain scenarios today. Consider suspects named by eyewitnesses only to be exonerated by DNA or verified alibis. Remember "hands up, don't shoot" eyewitnesses in Ferguson, Missouri?
TIMELINE:
There is a well-established timeline for the sinking. This includes what different people did at different times in the course of the night -- including when lifeboats were released. The ship itself stayed afloat for a remarkable amount of time too. A hull breach in the middle of the ship would not allow that to happen. Titanic sank in 2 hours and 40 minutes. By the time the ship is accepted to have broken apart, the bow was almost completely underwater. The timeline (and rate) of the sinking wouldn't make sense if the ship broke apart earlier. Moreover, there just wasn't enough buoyancy to make the bow rise. It is scientifically impossible.
WRECKAGE:
The remains of Titanic coincides with the commonly held belief about how the ship when down. The 2012 sinking theory by National Geographic and James Cameron -- particularly in terms of what happened after each ship went underwater -- coincides with everything we know about the remains of Titanic on the ocean floor.
CONCLUSION:
The V theory -- based upon just a few eyewitnesses -- just isn't plausible. Moreover, most advocates of this theory base their assumptions upon the drawings of Jack Thayer. Yet, in reality, Jack Thayer did not actually "see" the sinking from the perspective of the drawings.
Thayer and his friend jumped off the starboard side of Titanic amidship. He landed in the water, was nearly crushed by the second funnel, was shocked by the wave caused by that funnel before luckily feeling the overturned Collapsible B. He stated that he was helped up on it and was facing the ship.
Collapsible B had to be close enough to Titanic for all of this to happen. After all, after the breakup, he stated that the stern corkscrewed around to the point that the propellers were nearly above them (*and they feared that it would come crashing down on them).
Jack Thayer certainly witnessed the breakup. However, it was from this perspective at sea-level. He was never at a vantage point depicted in those drawings.
Now, I think that the perspective of Jack (according to his own testimony) might give a better image of what he saw. He was on the starboard side when the ship broke apart.
By most estimates, the ship took a sudden list to port. The list was sudden and violent enough to cause bodies on the stern to "pile up" (according to testimony of individuals like Charles Joughlin and others). That indicates not only a "yank" of the bow downward but a list to port dramatic enough to cause hundreds to lose their balance toward the same general direction.
To a person in the water on the starboard side, the sudden "yanked" notable list to port would seem to have made the ship "rise" (at least on the starboard side). This is especially true at the moment of the breakup (particularly if Collapsible B had drifted toward the aft of the ship (still on the starboard side). So, the angle of perspective of Thayer would have been from a vantage point at sea level and drifting slightly toward the rear of Titanic.
