[PSUBS-MAILIST] (no subject)

Thu Aug 27 09:25:29 EDT 2015

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 
> <br clear="none">
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> <b>
> <span style="font-weight:bold;">From:</span>
> </b>
>hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>;
><br clear="none">
> <b>
> <span style="font-weight:bold;">To:</span>
> </b>
>Personal Submersibles General Discussion
><personal_submersibles at psubs.org>; <br clear="none">
> <b>
> <span style="font-weight:bold;">Subject:</span>
> </b>
> Re: [PSUBS-MAILIST] new video <br clear="none">
> <b>
> <span style="font-weight:bold;">Sent:</span>
> </b>
> Thu, Aug 27, 2015 11:36:09 AM <br clear="none">
> </div>
> <br clear="none">
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>style="color:#000;background-color:#fff;font-family:HelveticaNeue,
>Helvetica Neue, Helvetica, Arial, Lucida Grande,
>sans-serif;font-size:12px;"><div><span>Alan,</span></div><div
>dir="ltr"
>id="yui_3_16_0_1_1440673788233_2986"><span>I am not sure if
>my </span>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.  </div><div
>dir="ltr"
>id="yui_3_16_0_1_1440673788233_2986">Hank</div> <br
>clear="none"><div class="qtdSeparateBR"><br
>clear="none"><br clear="none"></div><div
>class="yahoo_quoted" style="display:block;"> <div
>style="font-family:HelveticaNeue, Helvetica Neue, Helvetica,
>Arial, Lucida Grande, sans-serif;font-size:12px;"> <div
>style="font-family:HelveticaNeue, Helvetica Neue, Helvetica,
>Arial, Lucida Grande, sans-serif;font-size:16px;"> <div
>class="yqt1649066208" id="yqt52696"><div
>dir="ltr"> <font size="2" face="Arial">
>On Thursday, August 27, 2015 12:03 AM, Alan via Personal_Submersibles
><personal_submersibles at psubs.org> wrote:<br clear="none">
></font> </div> <br
>clear="none"><br clear="none"> <div
>class="y_msg_container"><div
>id="yiv1047596452"><div><div>Thanks Hank,</div><div>must be
>this one, the umbrella dive.</div><div><a rel="nofollow"
>shape="rect" target="_blank"
>href="https://m.youtube.com/watch?v=sflIEnkTth4">https://m.youtube.com/watch?v=sflIEnkTth4</a></div><div>Sent
>a reply to your post about using a second stage attached to
>your</div><div>ballast tank, but it didn't come back to
>me.</div><div>not sure how it would work!</div><div>Alan<br
>clear="none"><br clear="none">Sent from my
>iPad</div><div class="yiv1047596452yqt7882620191"
>id="yiv1047596452yqt69389"><div><br clear="none">On
>27/08/2015, at 1:30 pm, hank pronk via Personal_Submersibles <<a
>rel="nofollow"
>shape="rect">personal_submersibles at psubs.org</a>> wrote:<br
>clear="none"><br
>clear="none"></div><blockquote
>type="cite"><div><div
>style="color:#000;background-color:#fff;font-family:HelveticaNeue,
>Helvetica Neue, Helvetica, Arial, Lucida Grande,
>sans-serif;font-size:12px;"><div dir="ltr"
>id="yiv1047596452yui_3_16_0_1_1440638982967_2475">made some
>dive
>video's today, posted one on youtube under Hank
>Pronk</div></div></div></blockquote></div><blockquote
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