Re: [PSUBS-MAILIST] Hookah Sub (First Try)

[DJACKSON99@aol.com]

Sorry for the incomplete post  I cant type and eat at the same time!
 
> 2) I don't have enough info here, but if you want to descend to 33', how long 
> will it take your compresor to raise the volume of the cabin by 1 atm? 
Can it 
> give you the volume you need, fast enough?

It provides about 10 cfm at the surface.  But I was thinking about venting the ballast tanks throught the cabin too.

 I'm sure other ambients use
> bottled air which would compensate the cabin much faster. I'm curious to see the results of your calculations.
>
> 3)How long will your supply lines be? If you want to be able to descend to 
> 60', you might need lines a couple hundred feet long. How does having supply 
> lines that long affect the volume of air supplied? 


I plan to have air tanks along too if needed.  And they will be when I forget to fill the gas tank.  On hookah alone I am sure the accent will be much slower.  The system is designed to supply 4 divers at 65 feet, so we will rise sooner or latter.  We rarely go below 35 as there isnt much light, and if we dont exit for a dive the wait shouldn't be too long.
 

> Here's the clincher: I have a feeling that if you simply tow the hooka, a 
> slight  tug on the lines might pull your hooka under! When you use the hooka 
> for diving, you obviously can't pull hard enough with you mouth to do this, 
> but your proposed sub has hundreds? of pounds of thrust, and is vastly more 
> massive than your hooka float.. I think this is the real spoiler with this 
> particular design.


Yep, that would be a problem.  We can extend the lines to beyond 100' and in 60' of water depth will not be a issue but we have had the unit get snagged on trees and such.  I plan to learn how fast the sub can stop and the have twice that lenght of hose on the back deck.  Velcro will secure the line and when that pulls loose a simple dc switch would open and trigger an alarm in the cabin
.
> As an alternative, could you redesign your sub to put more of the structure on 
> the surface? How about a small barge that tows you behind it? Maybe the 
> underwater portion could have minor attitude adjusters, but to really move 
> from place to place, the barge would provide the main thrust.


I saw that ambiant glider on the web site and its what got me thinking about the investment I already have in the hookah.  I just wanted more control on the bottom end and want someting that my wife and I could use together without surface support.  Do you know if anyone is using that type of design.  Perhapse commercially for cable inspection/service?


> JP
>
>
> > > Hi all
> > >
> > > I am trying to design a low cost
> > > easy to construct,
> > > 2-person dry ambient submersible for shallow lakes (60 ft). Visibility is
> > > poor so speed is not important.
> > > Materials must be common and not special ordered.
> > > It must be able to be constructed using only hand tools and a welder.
> > > I want to be able to exit the sub while it's down for dives. The cabin
> > > cannot flood (much) when I exit to dive,
> > > and I want a second egress that allows me to stay relatively dry.
> > > It also has to weight less that 1 ton so its easy to tow, launch and
> > > recover.
> > > The primary air supply will be 3 air lines coming down from the surface
> > > where my towed hookah system will be following along. One of the line
> > > will be used for cabin air and ballast contorl the other 2 will have
> > > regulators and enter the sub through the dive hatch.
> > > Hookah means I can exit the sub without a BCD or scuba tank and very
> > > little weight. The hatch can therefore be relatively small.
> > > You can see my 1st design "H1" at
> > > http://members.cox.net/djackson99/sub/Sub_H1.htm
> > >
> > > I would love to see other designs that meet some of these requirements
> > > and I welcome any suggestions from the group.
> > >
> > > Thanks!
> > > Doug Jackson