Decompressing through an underwater horn shaped tunnel

[Jimijel]

Since the Titan sub disaster I have been thinking about the issue of protecting people from the dangers of the pressure changes associated with deep sea exploration. Reading about the Byford dolphin tragedy in particular was chilling. This was just a thought experiment of mine and I was wondering how feasible it was.

So take a horn shaped tunnel of solid steel and place the wide end on the sea floor and the narrow end on the surface. If a submarine where to travel through it, if my rusty high school level knowledge of physics is correct, the hydrostatic pressure acting on it will reduce as the diameter of the horn reduces (P= pgh). So if the sub travels slowly enough for the body to incrementally adjust, could this method get people safely from deep sea to the surface?

 

[hutchphd]

Sorry but your physics is in fact rusty (from the salt water!). The cross section matters not at all.

 

[Frabjous]

P=ρgh is the equation for incompressible water ignoring atmospheric pressure. More importantly, h is the depth.

 

[DaveC426913]

If the sub travelled slowly from the sea floor to the surface, the pressure on it is going to decrease to a safe level as it does so. Full stop. No horn.

So what exactly does the horn accomplish that is not accomplished without it? That's a rhetorical question for you to answer.

 

[russ_watters]

So what exactly does the horn accomplish that is not accomplished without it? That's a rhetorical question for you to answer.

I'd like to unrhetorical it: @Jimijel what exactly do you think the horn will do? And how do you think it relates to either the OceanGate or Byford dolphin tragedies?

 

[Flyboy]

If we're talking about the issues of pressure on the human body, we run into physiological issues long before mechanical/physics issues. Decompression sickness, anyone?

 

[sophiecentaur]

If we're talking about the issues of pressure on the human body, we run into physiological issues long before mechanical/physics issues. Decompression sickness, anyone?

There are two distinct issued to discuss here.

Firstly, a deep submersible maintains surface pressure inside it and the passengers' bodies are not affected by the outside pressure. At any significant depth, the hull has to be immensely strong to withstand the ambient pressure.

Secondly, without the protection by a rigid hull, our bodies can only tolerate a very moderate pressure. 40m is the limit of water depth that recreational scuba divers can tolerate safely and, even at that depth, there are time limits and 'stops' during the ascent. Deeper, extended diving requires long periods of decompression - I have read one day of slow decompression time per 100m of dive depth - to allow the dissolved gasses to be breathed out safely.