The Bathyscaph Trieste: Technological and Operational Aspects (1962)

Wikipedia: &quot;After passing 9,000 metres (30,000 ft), one of the outer Plexiglas window panes cracked, shaking the entire vessel.&quot;<p>If anyone else is curious about why the cracked window didn&#x27;t cause an implosion, I found the answer in an interview: it was a plexiglass window on the entrance tunnel, not the viewport that was part of the sphere.<p>&quot;A Plexiglas window in the flooded entrance tunnel had cracked under the pressure. But Walsh and Piccard were safe inside their cabin, separated from the tunnel by a thick steel hatch.&quot;<p><a href="https:&#x2F;&#x2F;spectrum.ieee.org&#x2F;don-walsh-describes-the-trip-to-the-bottom-of-the-mariana-trench" rel="nofollow noreferrer">https:&#x2F;&#x2F;spectrum.ieee.org&#x2F;don-walsh-describes-the-trip-to-th...</a>

- Main hull of the craft is a tank filled with gasoline: lighter than water and only a little compressible. It is not a high pressure enclosure. A membrane keeps these two fluids apart mostly, but some maneuvers dump gasoline into the ocean.<p>- Ballast is held in place with magnets. You actually want to drop ballast as you descend, to make up for the added seawater.<p>- Sphere on the bottom holds observer and instruments. This is a high pressure part.<p>- There’s no real propulsion or navigation. You land more or less where you land.

&quot;The float has the shape of a cylinder with tapered ends (sausage).&quot;<p>I love that they aren&#x27;t afraid to sound &quot;informal.&quot; I think there&#x27;s been a change in technical writing since this period -- technical and academic writers today are more concerned about sounding authoritative and less concerned with communicating clearly.

FNRS III&#x2F;DSV-0&#x2F;DSV-1 were engineered for fail-safe, elegant simplicity over cost and bulk. Power failure or operator opens the shot releases, and positive buoyancy is assured. There&#x27;s nothing in the buoyancy filler (gasoline &quot;balloons&quot;) that is ever not equalized with external pressure or could be crushed.<p>Archimède was a French Navy contemporary of the Trieste class but weighing 60% less.<p>Deepsea Challenger and Limiting Factor do away with 92% of 150 t of Trieste class mass to roughly 12 t each.<p>HeavensGate&amp; did away with another 2 t but couldn&#x27;t take <i>half</i> the pressure using unsound design, testing, and manufacturing processes and unproven materials in a rush to cash-in on commercial adventure experiences.<p>&amp; I meant OceansGate. Darwin Award engineering failures are best syncretized as an admixture of derision of crackpot approaches but with the seriousness of regulatory safety investigation failure chain analysis translated into an oft-repeated undergrad engineering case study. It also seems apparent to not overlook the breadth and depth of human factors extending into a myriad of areas including design, engineering, manufacturing, maintenance, rework, and testing regimes far beyond just operation. After blameless data gathering for exhaustive contributing factor analysis, final findings uncovering evidence of negligence should be severely punished by regulators (if there&#x27;s anyone still living to sue or foreclose on). <a href="https:&#x2F;&#x2F;www.faa.gov&#x2F;aircraft&#x2F;air_cert&#x2F;design_approvals&#x2F;human_factors" rel="nofollow noreferrer">https:&#x2F;&#x2F;www.faa.gov&#x2F;aircraft&#x2F;air_cert&#x2F;design_approvals&#x2F;human...</a>

Interesting that the overall concept of the Trieste is very similar to the Limiting Factor.<p>The main difference being instead of using gasoline as bouyancy, they use syntactic foam. It seems like that made the overall vessel smaller. But the fundamentals of the pressure vessel is very similar, with modern tech wrapped around inside and outside. And LF using Ti vs. the Trieste&#x27;s Steel vessel.<p><a href="https:&#x2F;&#x2F;lynceans.org&#x2F;tag&#x2F;syntactic-foam&#x2F;" rel="nofollow noreferrer">https:&#x2F;&#x2F;lynceans.org&#x2F;tag&#x2F;syntactic-foam&#x2F;</a>

Slightly obligatory Futurama quote:<p>Leela: Depth at 45 hundred feet, 48 hundred, 50 hundred! 5000 feet!<p>Farnsworth: Dear Lord, that&#x27;s over 150 atmospheres of pressure.<p>Fry: How many atmospheres can this ship withstand?<p>Farnsworth: Well it&#x27;s a spaceship, so I&#x27;d say anywhere between zero and one.

This was written by Don Walsh, who with Jacques Piccard, descended to the bottom of the Challenger Deep in 1960. It explains many engineering details.

A somewhat silly detail of the Trieste&#x27;s Challenger Deep dive is that there was a Rolex watch strapped to the <i>outside</i> of the vehicle. It survived.<p><a href="https:&#x2F;&#x2F;www.rolex.org&#x2F;perpetual&#x2F;trieste-the-deepest-dive" rel="nofollow noreferrer">https:&#x2F;&#x2F;www.rolex.org&#x2F;perpetual&#x2F;trieste-the-deepest-dive</a>

Basically, regular submarines blow compressed air into the ballast tanks when they need to surface. Because the Trieste goes so deep, compressed air wouldn&#x27;t work. It uses fine steel shot instead. But at this point, to make it neutrally buoyant, one needs a large amount of material that is only slightly lighter than water. It also has to be mostly incompressible, so aviation gasoline it is. The Trieste effectively becomes an underwater airship. Or a watership, if you will.

What a beautiful submission.<p>Yesterday I was reading about the Trieste in the Wikipedia. I had already seen an image of it years ago, but just yesterday I realized that only the small sphere was the place where the crew was in while the remainder was for navigation.

Interesting to note all the discussion of how aviation balloon materials aren&#x27;t suitable; I presume this is because Picard was most experienced with building balloons for high altitude exploration and applied similar techniques to the Trieste.

So many fascinating things in this report.<p>One was that the robot arm was made by General Mills (today, mostly a parent brand of breakfast cereal companies).

How many tons of gasoline has this craft put into the see?