[PSUBS-MAILIST] Drop weight design

[Alan via Personal_Submersibles]

Brian,
We discussed this a few years back, & I can remember Vance making 
some negative comments about the system, saying that on the slightest
interruption to the power the ballast would drop.
It may be that because the subs mentioned, are going so deep,
there are very few other alternatives.
I have a stack of magnets for fire safety doors, that keep doors open
& release them to close in event of fire. They don't seem to draw much
in the way of amps, from memory.
Of course you would have to epoxy them or something, & they would loose
a bit of power with the bigger gap caused by the insulation.
You would need a manual system to hold them in while transporting &
when the power was off for storage. 
A big plus would be the instantaneous response in an emergency, but
you could get that other ways.
Alan


Sent from my iPad

> On 18/09/2016, at 7:59 am, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> I wonder how many watts those electromagnets take?   I could do some tests to see what it would take to hold back the pressure of the shot.
>  
> Brian
> 
> --- personal_submersibles at psubs.org wrote:
> 
> From: via Personal_Submersibles <personal_submersibles at psubs.org>
> To: personal_submersibles at psubs.org
> Subject: Re: [PSUBS-MAILIST] Drop weight design
> Date: Fri, 16 Sep 2016 15:12:10 -0400
> 
> Oops, that would be Nautile, the French sub.
> 
> 
> s 
> -----Original Message-----
> From: via Personal_Submersibles <personal_submersibles at psubs.org>
> To: personal_submersibles <personal_submersibles at psubs.org>
> Sent: Fri, Sep 16, 2016 3:09 pm
> Subject: Re: [PSUBS-MAILIST] Drop weight design
> 
> The French didn't have anything to do with Trieste except for escort duty. It was built in Italy (in Trieste, don't you know) and belonged to Auguste Picard, who was Swiss. Then the US Navy. And yes, steel shot was used on all the bathyscaphs, including the French one, which was built later and called Archimede. And a few others, as well (like Nalutile). All of them had some variation of a ring electromagnet at the throat which served as a valve.
> Vance
> 
> 
> -----Original Message-----
> From: Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
> Sent: Fri, Sep 16, 2016 2:46 pm
> Subject: Re: [PSUBS-MAILIST] Drop weight design
> 
> Actually they used steel shot rather than lead, and the flow was started or stopped via an electromagnet. A benefit of this was that you could easily shed increments of weight, and another was that if you lost power, the sub would drop it's ballast automatically (i.e. fail-safe).
> 
> Best,
> 
> Alec
> 
> On Fri, Sep 16, 2016 at 8:48 AM, Jens Laland via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> Gentlemen,
> 
> If I'm not wrong, I think the French used a whole lot of off-the-shelf
> lead balls (as used in shotguns) in two individual pellet ballast
> hoppers when they operated the "Trieste" back in the 50's, ref
> https://upload.wikimedia.org/wikipedia/commons/3/31/Trieste_nh96807.svg
> 
> Best regards,
> Jens Laland
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