I have a ton of old B&W photos of the Bathyscaphe Trieste II if anyone is interested. I was stationed on her in 1970. She was undergoing a major refit after the operations to survey the Scorpion off the Azores. I also have some photos of the Trieste (one) in the Navy yard in DC somewhere. Probably the best book I have seen on the TI is
Seven Miles Down: The Story of the Bathyscaph Trieste: Jacques Piccard & Robert S. Dietz
Just to add to the history, the original Trieste was used to survey the remains of the Thresher a few years after her famous dive in the trench. I am not sure when but she was replaced by the Trieste II between the two submarine disasters. The TII had a working depth of 20,000'. The major difference was she could sit on deck without a cradle thanks to the addition of four legs. The TI required a pretty hefty crane to pull her out of the water and set in a cradle. Both had to be de-gassed to pull out of the water. The TII was supported by a floating dry-dock, the White Sands, and a tug of opportunity.
As far as I know, the TII's last major mission was surveying the remains of the Soviet submarine K-129 of Hawaii before the Glomar Explorer was built for Project Jennifer. I left for First Class Diving School weeks before she left for that deployment. Everyone was told it was a "Scientific Mission" and only a few people knew the actual purpose.
The technology behind the Bathyscaphes was to use gasoline (lots of it) for floatation. Iron shot was stored in silos fore and aft using an electromagnetic field as a valve. Shot was released for trim and fine buoyancy control but the idea was that all the shot would fall out when power was lost -- like when something goes wrong on the bottom and the batteries drain. For backup, both solos were held to the hull/gas tank by electromagnet levers so even if the shot got stuck the entire tub is dropped. All that gasoline is why they were so huge by today's standards. The TII held 67,000 gallons of Av-Gas.
Thankfully, syntactic foam eliminated the need for using gasoline as a virtually non-compressible buoyancy material. It varies by depth rating but the weight to volume ratio is far better than gasoline. It is basically bunch of varying size hallow glass spheres held together by epoxy. Most modern submersibles use it when needed, pump water for fine buoyancy control and trim, and drop weight (like batteries) for emergencies. Deeper boats today use Titanium hull$ and far more efficient batteries which dramatically reduces the amount of buoyancy required.
. My hope is the MPA's will make more of our ocean playgrounds like this. Sorry for the thread hijack.
