Trieste shortly after her purchase by the US Navy in 1958
|Builder:||Acciaierie Terni/Cantieri Riuniti dell'Adriatico|
|Launched:||26 August 1953|
|Fate:||Sold to the United States Navy, 1958|
|Reclassified:||DSV-0, 1 June 1971|
|Fate:||Preserved as an exhibit in the U.S. Navy Museum|
|Displacement:||50 long tons (51 t)|
|Length:||59 ft 6 in (18.14 m)|
|Beam:||11 ft 6 in (3.51 m)|
|Draft:||18 ft 6 in (5.64 m)|
Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe, which with her crew of two reached a record maximum depth of about 10,911 metres (35,797 ft), in the deepest known part of the Earth's oceans, the Challenger Deep, in the Mariana Trench near Guam in the Pacific. On 23 January 1960, Jacques Piccard (son of the boat's designer Auguste Piccard) and US Navy Lieutenant Don Walsh achieving the goal of Project Nekton.
Trieste was the first manned vessel to have reached the bottom of the Challenger Deep.
|This section does not cite any references or sources. (January 2011)|
Trieste consisted of a float chamber filled with gasoline (petrol) for buoyancy, with a separate pressure sphere to hold the crew. This configuration (dubbed a bathyscaphe by the Piccards), allowed for a free dive, rather than the previous bathysphere designs in which a sphere was lowered to depth and raised from a ship by cable.
Trieste was designed by the Swiss scientist Auguste Piccard and originally built in Italy. His pressure sphere, composed of two sections, was built by the company Acciaierie Terni. The upper part was manufactured by the company Cantieri Riuniti dell'Adriatico, in the Free Territory of Trieste (on the border between Italy and Yugoslavia); hence the name chosen for the bathyscaphe. The installation of the pressure sphere was done in the Cantiere navale di Castellammare di Stabia, near Naples. Trieste was launched on 26 August 1953 into the Mediterranean Sea near the Isle of Capri. The design was based on previous experience with the bathyscaphe FNRS-2. Trieste was operated by the French Navy. After several years of operation in the Mediterranean Sea, the Trieste was purchased by the United States Navy in 1958 for $250,000.
At the time of Project Nekton, the Trieste was more than 15 m (50 ft) long. The majority of this was a series of floats filled with 85,000 litres (22,000 US gal) of gasoline, and water ballast tanks were included at either end of the vessel, as well as releasable iron ballast in two conical hoppers along the bottom, fore and aft of the crew sphere. The crew occupied the 2.16 m (7.09 ft) pressure sphere, attached to the underside of the float and accessed from the deck of the vessel by a vertical shaft that penetrated the float and continued down to the sphere hatch.
The pressure sphere provided just enough room for two people. It provided completely independent life support, with a closed-circuit rebreather system similar to that used in modern spacecraft and spacesuits: oxygen was provided from pressure cylinders, and carbon dioxide was scrubbed from breathing air by being passed through canisters of soda-lime. Power was provided by batteries.
To withstand the enormous pressure of 1.25 metric tons per cm² (110 MPa) at the bottom of Challenger Deep, the sphere's walls were 12.7 centimetres (5.0 in) thick (it was overdesigned to withstand considerably more than the rated pressure). The sphere weighed 13 metric tons in air and eight metric tons in water (giving it an average specific gravity of 13/(13-8) = 2.6 times that of sea water). The float was necessary because of the sphere's density: it was not possible to design a sphere large enough to hold a person that could withstand the necessary pressures, yet also have metal walls thin enough for the sphere to be neutrally buoyant. Gasoline was chosen as the float fluid because it is less dense than water, incompressible even at extreme pressure, thus retaining its buoyant properties and negating the need for thick, heavy walls for the float chamber.
Observation of the sea outside the craft was conducted directly by eye, via a single, very tapered, cone-shaped block of acrylic glass (Plexiglas), the only transparent substance identified which would withstand the external pressure. Outside illumination for the craft was provided by quartz arc-light bulbs, which proved to be able to withstand the over 1,000 atmospheres of pressure without any modification.
Nine tons of magnetic iron pellets were placed on the craft as ballast, both to speed the descent and allow ascent, since the extreme water pressures would not have permitted compressed air ballast-expulsion tanks to be used at great depths. This additional weight was held in place at the throats of two hopper-like ballast silos by electromagnets, so in case of an electrical failure the bathyscaphe would automatically rise to the surface.
Transported to the Naval Electronics Laboratory's facility in San Diego, California, Trieste was modified extensively by the Americans, and then used in a series of deep-submergence tests in the Pacific Ocean during the next few years, culminating in the dive to the bottom of the Challenger Deep during January 1960.
The Mariana Trench dives
Trieste departed San Diego on 5 October 1959 for Guam aboard the freighter Santa Maria to participate in Project Nekton, a series of very deep dives in the Mariana Trench.
On 23 January 1960, she reached the ocean floor in the Challenger Deep (the deepest southern part of the Mariana Trench), carrying Jacques Piccard and Don Walsh. This was the first time a vessel, manned or unmanned, had reached the deepest known point of the Earth's oceans. The onboard systems indicated a depth of 11,521 metres (37,799 ft), although this was revised later to 10,916 metres (35,814 ft); fairly recently, more accurate measurements have found Challenger Deep to be between 10,911 metres (35,797 ft) and 10,994 metres (36,070 ft) deep.
The descent to the ocean floor took 4 hours 47 minutes at a descent rate of 0.9 metres per second (3.0 ft/s). After passing 9,000 m (30,000 ft) one of the outer Plexiglas window panes cracked, shaking the entire vessel. The two men spent barely twenty minutes on the ocean floor, eating chocolate bars for sustenance. The temperature in the cabin was 7°C (45°F) at the time. While at maximum depth, Piccard and Walsh unexpectedly regained the ability to communicate with the support ship, USS Wandank (ATA-204), using a sonar/hydrophone voice communications system. At a speed of almost a mile per second (about five times the speed of sound in air), it took about seven seconds for a voice message to travel from the craft to the support ship and another seven seconds for answers to return.
While at the bottom, Piccard and Walsh observed a number of small sole and flounder. Their claim the fish were swimming would prove at least some vertebrate life can withstand the extreme pressure at the oceans' deepest point. They noted that the floor of the Challenger Deep consisted of "diatomaceous ooze". The ascent took 3 hours 15 minutes.
Other deep dives by Trieste
Beginning in April 1963, Trieste was modified and used in the Atlantic Ocean to search for the missing submarine USS Thresher (SSN-593). Trieste was delivered to Boston Harbor by USS Point Defiance (LSD-31) under the command of Captain H. H. Haisten. In August 1963, Trieste found the wreck off the coast of New England, 8,400 ft (2,600 m) below the surface. Trieste was changed, improved and redesigned so many times that almost no original parts remain. She was transported to the Washington Navy Yard where she was exhibited along with the Krupp pressure sphere in the National Museum of the U.S. Navy at the Washington Navy Yard in 1980. Her original Terni pressure sphere was incorporated into the Trieste II.
In art and literature
The song 'The Trench' by Danish composer Ste van Holm is a tribute to the Mariana Trench dives.
The producers of the TV show Star Trek: The Next Generation named ship's captain Jean-Luc Picard after Jacques Piccard. They would later name one of the show's starships the U.S.S. Trieste, after the bathyscaphe. She was noted for being small and slow. 
|This article may be expanded with text translated from the corresponding article in the Norwegian (bokmål) Wikipedia. (May 2013)|
- Amos, Jonathan (7 December 2011). "Oceans' deepest depth re-measured". BBC News. Retrieved 7 December 2011.
- NGC: On the sea floor
- To the Depths in Trieste, University of Delaware College of Marine Studies
- Seven Miles Down: The Story of The Bathyscaph Trieste., Rolex Deep Sea Special, Written January 2006.
- "Wandank (ATA-204)". historycentral.com. Retrieved 3 June 2009.
- Meet the only man alive who has been to the deepest ocean (in English). BBC. 2012. Retrieved 24 February 2012.
- "Meet the creatures that live beyond the abyss". BBC. 22 January 2010. Retrieved 24 February 2012.
- Brand, V (1977). "Submersibles - Manned and Unmanned". South Pacific Underwater Medicine Society Journal 7 (3). ISSN 0813-1988. OCLC 16986801. Archived from the original on 1 August 2008. Retrieved 10 July 2008.
- Okuda, Michael; Okuda, Denise (1999). The Star Trek Encyclopedia. Pocket Books. p. 360. ISBN 0-671-03475-8.
- Okuda, Michael; Okuda, Denise (1999). The Star Trek Encyclopedia. Pocket Books. p. 522. ISBN 0-671-03475-8.
- Piccard, Jacques and Dietz, Robert S. (1961). Seven Miles Down; The Story of the Bathyscaph Trieste. G. T. Putnam's Sons.
|Wikimedia Commons has media related to Trieste (submarine, 1953).|
- US Navy - Trieste
- Animation of Trieste
- HNSA Ship Page: RV Trieste
- History of the Bathyscaphe Trieste
- 50th anniversary recollection by retired Navy Captain Don Walsh.
- 2008 obituary of diver Jaques Piccard
- Seven Miles Down the story of the Bathyscaphe Trieste