# Physics of Hoisting Up Submersible Near Titanic **URL:** \ **Category:** Factual Questions\ **Created:** [June 22, 2023, 1:11am UTC](https://boards.straightdope.com/t/physics-of-hoisting-up-submersible-near-titanic/985912 "2023-06-22T01:11:37Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![Caribbean\_cruiser](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/caribbean_cruiser/32/9349_2.png) [@Caribbean\_cruiser](https://boards.straightdope.com/u/Caribbean_cruiser)\ **Post date:** [June 23, 2023, 9:02pm UTC](https://boards.straightdope.com/t/physics-of-hoisting-up-submersible-near-titanic/985912/21 "2023-06-23T21:02:51Z")
“I’m surprised they’re missing what would be leementary precautions, like a pinger and a big hook to attack a winch cable, not to mention the capability to haul it up if necessary (plus rover to find it) on board the launch ship itself.” Guiding a submersible into crushing ocean depths via a plastic game controller speaks volumes of the CEO’s hubris. Despite being a Princeton-educated engineer, he scoffed at the laws of physics and embraced risk, despite a Greek chorus warning of impending doom. The shattered hull of his “invincible” submersible now rests near the “unsinkable” Titanic, making it a bonus side-trip for future Titanic tourists. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [June 23, 2023, 9:14pm UTC](https://boards.straightdope.com/t/physics-of-hoisting-up-submersible-near-titanic/985912/22 "2023-06-23T21:14:27Z")
Various experts have opined than in another century at most the _Titanic_ will have degraded into a reddish-brown spot on the seafloor, substantially the entire hull and machinery eaten away by bacteria and sea life. Leaving the carbon composite hull of _Titan_ as the sole big structure down there. Ozymandias would be so proud. ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [June 23, 2023, 10:01pm UTC](https://boards.straightdope.com/t/physics-of-hoisting-up-submersible-near-titanic/985912/23 "2023-06-23T22:01:49Z")
> [@LSLGuy](#): > > That exact issue has been covered by a bunch of folks over in the breaking news thread about the _Titan_. A little strategic murder done early enough does have its attractions. I was reminded of an Onion article that paraphrased read as; “In retrospect we may have resorted to cannibalism prematurely, but the elevator had been stuck for over an hour, and some of us had missed lunch”. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [June 24, 2023, 12:58am UTC](https://boards.straightdope.com/t/physics-of-hoisting-up-submersible-near-titanic/985912/24 "2023-06-24T00:58:04Z")
> [@Caribbean\_cruiser](#): > > The shattered hull of his “invincible” submersible now rests near the “unsinkable” Titanic, making it a bonus side-trip for future Titanic tourists. I do have to wonder about the advisability of showing passengers of a submersible the remains of a submersible that didn’t make it. Yeah, most people probably wouldn’t freak out, but there’ll be a few that let their imagination go wild. ---
**Author:** ![Seren359](https://avatars.discourse-cdn.com/v4/letter/s/a87d85/32.png) [@Seren359](https://boards.straightdope.com/u/Seren359)\ **Post date:** [June 24, 2023, 10:15am UTC](https://boards.straightdope.com/t/physics-of-hoisting-up-submersible-near-titanic/985912/25 "2023-06-24T10:15:00Z")
> Blockquote I do have to wonder about the advisability of showing passengers of a submersible the remains of a submersible that didn’t make it. Yeah, most people probably wouldn’t freak out, but there’ll be a few that let their imagination go wild. It’s human nature, the first thing that any future visitors are going to want to see will be the remains of this sub. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [June 24, 2023, 5:38pm UTC](https://boards.straightdope.com/t/physics-of-hoisting-up-submersible-near-titanic/985912/26 "2023-06-24T17:38:39Z")
> [@Dr.Strangelove](#): > > _Almost_ uniformly. The pressure on the bottom is a little bit more than that at the top, and that is what causes buoyancy. I keep thinking there should be an integral with respect to depth. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [June 24, 2023, 9:45pm UTC](https://boards.straightdope.com/t/physics-of-hoisting-up-submersible-near-titanic/985912/27 "2023-06-24T21:45:40Z")
If you want to be as accurate as possible, certainly. Since water is a tiny bit compressible, and the density also varies with temperature, the density at any given depth depends on the entire state of the water above it–which in turn depends on the water above it. So you have to sum up infinitesimal layers as you go down. Fortunately, these factors are _fairly_ small, even kilometers down. Water really is very nearly incompressible. And in the case of bouyancy specifically, you pretty much never have to consider the density variation across the water column height. Vessels aren’t hundreds of meters tall (though maybe some oil platforms do take it into account…). ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [June 24, 2023, 10:41pm UTC](https://boards.straightdope.com/t/physics-of-hoisting-up-submersible-near-titanic/985912/28 "2023-06-24T22:41:56Z")
Salinity gets a vote too. Which also varies with depth and location just as temperature does. As a practical matter you design your machinery against some standard ocean model, plus some fudge for extra cold, extra salty, extra deep = extra3 dense. Then you in effect “weigh” the water where you are right now by adjusting ballast, or cable tension, or hydrodynamic forces to balance everything out. [Previous page](https://boards.straightdope.com/t/physics-of-hoisting-up-submersible-near-titanic/985912.md?page=1)