Re: [PSUBS-MAILIST] An Idea for a PSUB Periscope

["Gary R. Boucher" <protek@shreve.net>]

     It's not that easy.  Lets say you get a pump.  It has to be a low 
voltage pump unless you plan to use a converter.  Pumps designed to work on 
the surface will not necessarily work 20 feet below the surface.  You may 
have to pressure compensate the pump.  You could put the pump inside the 
hull but then you have to have some way to get the water through the hull 
interface.  Of course the pump will have to be able to handle the pressure 
at depth.
     The double pane idea seems reasonable at first but the problem you 
have is two-fold.  Not only are you trying to make the outside temperature 
of the tube as low as possible you WANT the heat generated inside the 
camera to pass through the tube and on our, otherwise the temperature 
inside will increase till there is damage.  You want conduction through the 
tube, as much as possible.  You just want the tube to be a good radiator of 
the heat absorbed and generated.  What would help would to be to place a 
shield on top of the tube where air can circulate under the shield.  This 
would place the tube in the shade in essence lowering the temperature that 
would exist if exposed to sunlight.
     BTW whatever method you use has to be able to stand the pressure.
     I took some photos with my digital camera of what I have, but am 
having some trouble uploading them into the computer.  I will get them 
uploaded one way or the other.  When I do, I will send photos of my design 
out to anyone interested if they will send me an email.

Gary Boucher


>Heat isn't a problem.  We have billions of gallons of cooling water 
>:)  get a small edmound scientific pump, or winshield wiper pump, or 
>whatever pump you have handy. and run water up through a coil or cooling 
>jacket inside the camera housing.  if the housing is dry when you make it 
>you won't have condensation problems.  of if that's too much of a concern 
>create a thermal window pane (2 layers with an insulating air gap)  and 
>that should solve all your cooling problems :)
>
>*********** REPLY SEPARATOR  ***********
>
>On 8/7/00 at 9:33 AM Karl Fuller wrote:
>
> >Gary, thanks for passing on the benefit of your experience. I had planned to
> >use such a camera.Never would have thought the internal/external heat thing
> >would be a problem, now I know. If you don't post the info to the group, I
> >would like to have it too thanks. fullerk@voyager.co.nz
> >
> >Regards, Karl.
> >