[PSUBS-MAILIST] (no subject)

Thu Aug 27 10:27:37 EDT 2015

Sean,This is the big debate, VBT or no VBT.  I used to like the idea of no VBT and that is the way the Nekton subs operate, just not sure anymore.  I have to admit, my regulator idea is riddled with potential problems.  I am just being lazy, if I keep the sub with in 15 lbs (as per the operating manual)  or less of buoyant with tanks flooded, and I pay attention, it is easy to operate.   I can sink as slow as I want and hover at any depth if I take my time.   I need to correct a bad habit  that I have.  I know the bottom is soft, so I sink fast.  I need to practice what I preach and always sink as if there is a hard hazard below.  Hank 

     On Thursday, August 27, 2015 7:26 AM, Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Hank, your best bet is to arrange your MBTs such that they flood completely every time with no residual bubble(s), at which point you should have very slight positive buoyancy when correctly ballasted. Add a small VBT, either internally or externally in a hard tank (you could blow this with HP air instead of pumping, but would need to valve it to isolate it from ambient pressure changes), to compensate for minor crew weight differences, and compensate for the major ones by adding or removing lead.You want to avoid a situation where a depth change creates a buoyancy change, except in the sole case where you have blown your tanks to ascend.Sean

On August 27, 2015 7:13:27 AM MDT, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

| Alan,
It won't work unless there is a check valve between the second stage regulator and the ballast tank. Okay to complicated, bad idea.
Hank 

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 hank pronk via Personal_Submersibles ; 

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 Personal Submersibles General Discussion ; 

 Subject:

 Re: [PSUBS-MAILIST] new video 

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 Thu, Aug 27, 2015 11:36:09 AM 

| Alan,I am not sure if my idea will work .  When I sink Gamma, there is an air bubble remaining in the ballast tank, the size  is determined by the weight of the sub.  If I have a first and second stage regulator feeding air to the ballast tank, the regulator will feed air into the ballast tank as I sink keeping the bubble the same size while I sink.  Right now it is completely manual and takes practise but it works.  I can use both systems ( manual or regulated) by simply turning the air supply on or off to the external regulators.   With the regula! torsystem, I would not have to worry about keeping the sub at an ideal weight.  Hank 

     On Thursday, August 27, 2015 12:03 AM, Alan via Personal_Submersibles wrote:

 Thanks Hank,must be this one, the umbrella dive.https://m.youtube.com/watch?v=sflIEnkTth4Sent a reply to your post about using a second stage attached to yourballast tank, but it didn't come back to me.not sure how it would work!Alan

Sent from my iPad
On 27/08/2015, at 1:30 pm, hank pronk via Personal_Submersibles personal_submersibles at psubs.org> wrote:

made some dive
 video's today, posted one on youtube under Hank Pronk

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     From:  hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>; 
  To:  Personal Submersibles General Discussion <personal_submersibles at psubs.org>; 
  Subject:  Re: [PSUBS-MAILIST] new video 
  Sent:  Thu, Aug 27, 2015 11:36:09 AM 

| Alan,I am not sure if my idea will work .  When I sink Gamma, there is an air bubble remaining in the ballast tank, the size  is determined by the weight of the sub.  If I have a first and second stage regulator feeding air to the ballast tank, the regulator will feed air into the ballast tank as I sink keeping the bubble the same size while I sink.  Right now it is completely manual and takes practise but it works.  I can use both systems ( manual or regulated) by simply turning the air supply on or off to the external regulators.   With the regulator system, I would not have to worry about keeping the sub at an ideal weight. Hank 

     On Thursday, August 27, 2015 12:03 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Thanks Hank,must be this one, the umbrella dive.https://m.youtube.com/watch?v=sflIEnkTth4Sent a reply to your post about using a second stage attached to yourballast tank, but it didn't come back to me.not sure how it would work!Alan

Sent from my iPad
On 27/08/2015, at 1:30 pm, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

made some dive video's today, posted one on youtube under Hank Pronk

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