[PSUBS-MAILIST] Vacuum vacuum

[Alan via Personal_Submersibles]

Brian,
I am wondering if it is worth doing!
None of the Psubs do it that I know of ( correct me if I'm wrong).
If you pulled a vacuum & the sub stayed at that pressure then you
would need to pressurise the hull to get out! But good test to see 
that the hatch is sealing ok.
Alan

> On 30/04/2019, at 11:03 AM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Hi All,
>                    Tried the Vacuum cleaner , shop vac , method of pulling a vacuum on the sub today.   Works really great!   I pulled about neg 2 psi and it pulled the hatch down instantly and is holding nicely.  The large volume of air vacuum works a lot better than using a vacuum pump since it tends to pull surface area of the hatch all at once , where as when using the vacuum pump I remember having to sit on the hatch to make it grab.   I'm trying to remember Phil Nuytten's procedure after the vacuum is pulled, was it to bring the cabin pressure gauge dial back to zero by turning the dial indicator?  And with his bellows add system there was another adjustment I believe.  
> 
> Brian
> 
> 
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