[PSUBS-MAILIST] Re: Your Message Sent on Thu, 14 Feb 2002 13:38:48 +0000

[Ray Keefer <Ray.Keefer@Sun.COM>]

Hi Kim,

The problem with wet subs is that they are ambient pressure subs. 
The physiological effects on the human body ARE relavant. The
mere fact that if you hold your breath at 10 feet will kill you
if you surfaced because your lungs will expand and explode.

Or stay down too long and you get into decompression issues.

While you can design a simple wet sub that the operator only needs a
"minimum knowledge" about. The user really needs the equivelant knowledge 
of a scuba diver to be safe. 

You should consider taking a scuba diving class to understand first hand
the environment your operator will have to survive.

Design issues are many. Here are a few:

	Power source, battery? If so then how to keep water out? Keep 
	the terminals from shorting out in the water. How to keep the
	water out of the batteries.
	
	Motive source, electric motors. How do you keep the water out?
	Use shaft seals of some kind? Pressure compesation of the motor
	housing.
	
	Control surfaces should be simple enough with cables, pulleys, shafts
	and linkages.
	
	In a fully flooded wet sub the humans will have to breath through
	scuba regulators. If the operators are in an air bubble you will 
	still have to supply air. So a compresses air system will have to
	be provided.
	
	Emergancy drop weight? Dangerous in an ambient pressure sub.
	See above about lungs exploding. The release needs to be
	very secure to prevents any unintentional release and
	should be sized into small enough chunks of weight that 
	controlled amounts can be dropped at a time. What you
	don't want is to drop all your weight at once and to
	rocketing to the surface. A gradual climb at less then
	60ft/minute is good.
	

Regards,
Ray



> X-Originating-IP: [192.173.4.8]
> From: "Kimmy Lim" <kllling@hotmail.com>
> To: Personal_Submersibles@psubs.org
> Date: Thu, 14 Feb 2002 13:38:48 +0000
> X-OriginalArrivalTime: 14 Feb 2002 13:38:48.0509 (UTC) 
FILETIME=[EE710ED0:01C1B55C]
> 
> I am an industrial designer currently doing a project on a personal 
> underwater craft . The objective of it is to design a wet sub which allows 
> user to go corals and reefs diving with the minimum knowledge to use the 
> underwater craft. What are the basic knowledge that I should know in order 
> to design one? Are there any design problems that I could solve as a 
> designer?
> 
> Please advice. Thanks
> 
> Kimmy
> 
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