[PSUBS-MAILIST] Progress report

[Alan via Personal_Submersibles]

Hi Brian,
this is what can happen if you get your ballasting wrong.
https://m.youtube.com/watch?v=CGu6tpYpXLE
It is the Chinese oil barrel submarine having to be pulled out of the water.
I guess he has gotten in to such an angle that any ballast air he feeds in
goes straight out the bottom vent.
Alan

Sent from my iPad

> On 16/08/2014, at 11:40 am, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Thanks Alec, That means a lot coming from you.  Your project was the first one that peeked my interest the very first time I found the Psubs web site.    The inside is actually baffled but not really on purpose.  There are ribs that are part of the frame work on the inside every 18 inches.  However I was worried that the air trapped in there would make for less control ( not being able to keep a neutral buoyancy condition)  because Ideally you want your soft ballast tank completely flooded, so I put holes at the top of the ribs so I could completely flood the soft ballast.  But listening to Vance tell about "riding the bubble" I'm really not sure what the best procedure would be.   I have bottom vents in two locations, the front vent I will probably cap off because if the front got too high air could potentially escape from there.
>  
>   I don't want to get into a situation where the shrinking air bubble, while descending, sends me to the bottom before I can compensate for the reduction of the buoyancy . 
>  
> Brian     
> 
> --- personal_submersibles at psubs.org wrote:
> 
> From: Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Progress report
> Date: Sat, 16 Aug 2014 10:34:34 -0400
> 
> Hi Brian,
> 
> I really enjoyed that because its in every way so radically different to any other design. I've always wondered how you would see anything, and that the sphere end might make a better bow for that reason, so the most interesting comment to me was that you intend to use go in one direction when diving and the opposite direction on the surface or mid-water. I never thought of that. My other big concern would be the free surface effect of such long MBTs. Are they baffled or sub-divided? If not, I'm afraid I'd you could have serious instability when MBTs are partially flooded, which is to say when diving or surfacing the boat. The instability could also end up putting the boat in a position such that the vents are no longer at the highest spot of the MBTs.
> 
> Thanks,
> 
> Alec 
> 
> 
> On Sat, Aug 16, 2014 at 3:25 AM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> I did a video of the present state of my sub.  Been making some significant progress,  once the conning tower and hatch are on I'll feel a lot better - and the viewports.
>  
> https://www.youtube.com/watch?v=luabNVU0QW0
>  
> Brian
> 
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