From what I understand, working from a tired memory, the third piece was part of the ship's bottom around the area of the break. Since it was the ship's bottom, I suppose it's unlikely that it would have been above water for anyone to see -- since I don't believe Titanic was more than fifteen or twenty degrees or so by the bow when her hull failed.
You need an expert. Let's hope a techie, perhaps Roy Mengot, will pop in.
Well, quite a few people saw well enough to know that the ship had broken in two. Check out day 8 of the testimony in the U.S. Senate inquiry. For all that, nobody could see what was happening underwater which was where this section of double bottom seperated from the rest of the hull.
There was a documentary back in 2001 I believe where an expedition to map the Titanic site for posterity revealed the "third piece" of the Titanic's hull and it was remarkably intact, though laying on it's starboard side however. The large section is believed to contain the other half of the ship's engine as well as some intact boilers. Now as for where it separated, I would have to say it left the ship below water because when the bow and stern wrenched free from each other, that third piece, along with the keel plate were the only two items holding the ship together, so when it broke free I believe it was the first part of the ship to hit bottom, maybe a few minutes ahead of the bow.
I don't mean to be patranising but what third piece. Nobody saw it during the sinking and no one saw it when Dr. Robert Ballard discovered it. It's possible but unfortunately i didn't get to see the recent expeditions
Since the portion we're talking about is a large section of the double bottom, I'd be very surprised if anyone saw it come off even if the breakup had happened in broad daylight. This section was found in the debris field between the bow and stern sections.
Also, I'd say it's a fair bet that somebody "saw" it when it was discovered by the Ballard expedition. It just didn't become widely known until the later expeditions were presented by the Discovery Channel.
Yes I saw it on video from the 98 expedition. It likely broke when the aft expansion joint let go. The bottom was in anticlastic bending, so there would have been two stress hot spots, which is where she broke.
Cassie, the expeditions were extensively covered by the Discovery channel's documentaries such as Titanic, Answers From The Abyss and Titanic, The Investigation Begins. The latter, if I recall correctly, was the one where they presented the first attempt to recover the section of hull plating known as The Big Piece.