Re:AIPs,WaterJets and Propulsion

[Mike Young <tvcmikey@yahoo.com>]

Mike here,from Malaysia,
The design I've been working on for a submersible is in the shape of a
giant manta ray, using a waterjet propulsion system. The intake in
front and the propulsion from what would be its tail. The air to water
ratio you mentioned could be taken care of by a vacuum created to
remove CO2 at the same time and replacing the air in the sub by using
two large pressurized tanks, one pure oxygen, the other plain
compressed air (like a regular scuba tank), and both holding about 6
hours worth. Water flow can also be used for steering with a small
trolling motor to get water flow started when you start up your dive.
I noticed a picture of a deep submersible(3000+ ft.) which used
pressure banding to hold a clear bow dome in place and to seal the
whole thing to the metal hull. Once I can scan the picture into my
computer, I'll try to send it as an attachment.




---Sean Walinga <swalinga@telusplanet.net> wrote:
>
> 
> 
> >        Is waterjet propulsion for a relatively *slow* moving
object like
> >a personal submarine practical?  I know it's used on some speed
> >boats, and on "jet ski" type watercraft.  Seems like I've read or
heard
> >that waterjet propulsion isn't practical for slower moving vehicles.
> 
> I have looked into this one a little. The air to fluid ratio in a
jetski waterjet is
> crucial. The air is mandatory in the vaccum created within the
waterjet. Also; the
> jet thrust creates a turbulence in the water located behind the jet.
This is
> difficult to design around if this trailing water is in contact with
your sub. The
> net effect is a craft that doesn't track properly and also shudders...
> 
> The air needed is also an issue in a sub...
> 
> >        It seems to me that a waterjet system would eliminate the
> >problems [if any] associated with sealing a through-hull drive shaft
> >turning a propeller.  It would also eliminate any dangers a spinning
> >prop would have on anyone swimming near the sub.
> 
> The waterjet still needs the driving shaft. This means that you
still have the
> "problem".
> 
> If safety is an issue, you may consider a caged propellor. Like the
air fan in your
> home (except different).
> 
> ttfn
> Sean
> 
> 
> 

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