Why is it that deep sea creatures can withstand huge amounts of pressure when submarines made of steel and alloys cannot?

It's kind of strange that you include real subs with pie-in-the-sky fake ones. Specifically the Triton 36000 that you've linked. It does not exist. It may never exist. Or if they actually get around to building one, they may find that they have to trash the whole designs and start from scratch.

Far as I can tell, the company has only sold the Triton 1000's and a single Triton 3300. They built the prototype in 2012 and the single sale makes their News page.

Building submarines for 1000 feet or 3300 feet is a hell of a different thing than building one rated for 36,000 feet. The materials and design change completely, one is not just a scaled up model of another. None of their hatch technologies would work at 36,000 feet. Nothing at all can be allowed to pierce the glass shell.

They talk about designs to overcome these constraints, but they haven't even built a prototype, nothing that has actually been tested in any ocean. On one page they claim they will sell you one within 18 months of payment, but on another page they warn that they're in the habit of using "forward looking statements" so don't even think of suing if they turn out to be wrong.

Some of their claims are just unbelievable, like for the Triton 36,000 they say "pay for your submarine by providing adventure dives for $250,000 per seat". That is just so fucking ridiculous. Assuming the submarine costs a few million, it would take a dozen dives to pay just for the submarine, not counting launch ship costs at all, which would likely double or triple the cost. So they are claiming that not only can this submarine dive to 36,000 feet, it can do it repeatedly a dozen times or more.

No submarine (or even unmanned submersible) that has gone down that deep can repeat the feat without an extensive overhaul that practically amounts to rebuilding it. Trieste never repeated its dive to the bottom of the Challenger Deep, it was displayed at exhibitions for a bit then sold. Most of it was scrapped except the pressure hull, which was bought by the US Navy and became part of the Trieste II. But it was downrated to 20,000 feet only. Cameron's Deep Sea Challenger never made another dive, despite his numerous statements about a planned series of 4-6 dives. It did just the one and then was promptly shipped off to a museum. Damn near everything broke down when he reached bottom - the robot arm got stuck, 3 of his 4 maneuvering propellers failed, all he could do was spin around in the same spot for a couple minutes, then he dropped weights and ran for the surface.

And yet this company that hasn't even built a prototype claims it can build one for a third the cost, for 3 passengers, not one, in a fully glass shell not steel, and be good for multiple dives so you can "pay the cost off" with paying passengers?

It stinks of bullshit.

/r/askscience Thread