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Very cool. Does need to be updated since the deepest discovered shipwreck is no longer the USS Johnston[1] as of 2022. > The wreck of Samuel B. Roberts lies at

Very cool. Does need to be updated since the deepest discovered shipwreck is no longer the USS Johnston[1] as of 2022. > The wreck of Samuel B. Roberts lies at a depth of 6,895 meters (22,621 ft; 4.284 mi), making her the deepest known shipwreck and the deepest shipwreck ever identified by a crewed submersible. It exceeds the previous record of 6,469 meters (21,224 ft; 4.020 mi), set in March 2021 when Vescovo's team found and identified the wreck of the destroyer USS Johnston, which was sunk in the same battle. [1] https://en.wikipedia.org/wiki/USS_Samuel_B._Roberts_(DE-413)#Discovery_of_wreck https://en.wikipedia.org/wiki/USS_Samuel_B._Roberts_(DE-413)...

gausswho 3y ago
How is it the structure of a ship, even thin bars of steel, can withstand the pressure of that depth? How many pounds per square inch would be applied here? Is the pressure a danger for submersibles because of the pressure differential rather than the pressure itself?
- gostsamo 3y ago
  If the ship hulk is full of water, the pressure is on both sides. Worst that can happen to such a material is to be compressed, but metal is okay in that regard.
- giantrobot 3y ago
  Pressure differential is definitely one of the bigger problems. In a manned submersible the interior pressure is usually roughly sea level. So you've got hundreds of atmospheres on the outside vs one of the inside. Anything that requires some pressure differential requires a strong pressure vessel. So not just the crew compartment but also camera housing and the like. This is all compounded by the fact the deep ocean is very cold so as a submersible descends there's a thermal gradient with "survivable" on the inside and sun-zero on the outside. Temperature differentials interact with the pressures because the atmospheric pressure and low temperature will both cause material to compress/contract. The whole vessel structure needs to be able to remain structurally sound with all of that expansion and contraction. The submersible is also in salt water which corrodes different materials and can cause electrical shorts. A submersible could have a few successful missions then fail because some corrosion was missed on an inspection. Building a manned or unmanned device to travel to and return from an extreme environment is really hard. You need to understand or at least make educated guesses about the target environment, understand your building materials, your construction processes, validate and bench test as much as possible, and have the same amount of thought go into actual operations. "Fuck it we'll do it live" is not a recipe for success.

gausswho 3y ago

How is it the structure of a ship, even thin bars of steel, can withstand the pressure of that depth? How many pounds per square inch would be applied here? Is the pressure a danger for submersibles because of the pressure differential rather than the pressure itself?

gostsamo 3y ago
If the ship hulk is full of water, the pressure is on both sides. Worst that can happen to such a material is to be compressed, but metal is okay in that regard.
giantrobot 3y ago
Pressure differential is definitely one of the bigger problems. In a manned submersible the interior pressure is usually roughly sea level. So you've got hundreds of atmospheres on the outside vs one of the inside. Anything that requires some pressure differential requires a strong pressure vessel. So not just the crew compartment but also camera housing and the like. This is all compounded by the fact the deep ocean is very cold so as a submersible descends there's a thermal gradient with "survivable" on the inside and sun-zero on the outside. Temperature differentials interact with the pressures because the atmospheric pressure and low temperature will both cause material to compress/contract. The whole vessel structure needs to be able to remain structurally sound with all of that expansion and contraction. The submersible is also in salt water which corrodes different materials and can cause electrical shorts. A submersible could have a few successful missions then fail because some corrosion was missed on an inspection. Building a manned or unmanned device to travel to and return from an extreme environment is really hard. You need to understand or at least make educated guesses about the target environment, understand your building materials, your construction processes, validate and bench test as much as possible, and have the same amount of thought go into actual operations. "Fuck it we'll do it live" is not a recipe for success.