<font color='black' size='2' face='arial'>
<div><font size="3">The Navy training film on youtube I linked to earlier is from 1955 and not from WW2. Here's a good, brief article of historical development of saddle tanks on military subs. Since the mid-1950s most military subs have had their ballast tanks <em>inside</em> the pressure hull. </font><a href="http://en.wikipedia.org/wiki/Saddle_tank_(submarine">http://en.wikipedia.org/wiki/Saddle_tank_(submarine</a>)</div>
<div> </div>
<div><font size="3">Surprisingly the ballast tanks on WW1 German subs were low inside the pressure hull with flat tops. This sometimes presented problems when the crew needed to blow at depth. </font></div>
<div><font size="3"></font> </div>
<div><font size="3">Jim</font></div>
<div> </div>
<div><font size="3"></font> </div>
<div></div>
<div></div>
<div style="color: black; font-family: arial,helvetica; font-size: 10pt;">-----Original Message-----<br>
From: Joe Perkel <josephperkel@yahoo.com><br>
To: personal_submersibles <personal_submersibles@psubs.org><br>
Sent: Sat, Nov 30, 2013 5:50 am<br>
Subject: Re: [PSUBS-MAILIST] Stability & Buoyancy<br>
<br>
<div id="AOLMsgPart_2_e7deb527-2687-41cf-a31b-096c4f8c2a3d">
<table border="0" cellspacing="0" cellpadding="0"><tbody><tr><td valign="top">BTW Alan, that document you stumbled upon is an excerpt from the NAVPERS 16180 Fleet Type Submarine manual from WW2. I have had a copy of this on CD for years and this manual while chock full of interesting and informative stuff, it has been the single biggest influence on me with regards to an upward design spiral. <br>
<br>
Stop reading it, it's pure evil! )<br>
<br>
Joe<a href="http://overview.mail.yahoo.com?.src=iOS" target="_blank"><br>
<br>
Sent from Yahoo Mail for iPad</a></td></tr></tbody></table>
<div id="_origMsg_">
<div>
<br>
<div>
<div style="font-size: 0.9em;">
<hr size="1">
<b>
<span style="font-weight: bold;">From:</span>
</b>
<a href="mailto:MerlinSub@t-online.de">MerlinSub@t-online.de</a> <<a href="mailto:MerlinSub@t-online.de">MerlinSub@t-online.de</a>>; <br>
<b>
<span style="font-weight: bold;">To:</span>
</b>
Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>; <br>
<b>
<span style="font-weight: bold;">Subject:</span>
</b>
Re: [PSUBS-MAILIST] Stability & Buoyancy <br>
<b>
<span style="font-weight: bold;">Sent:</span>
</b>
Sat, Nov 30, 2013 10:51:00 AM <br>
</div>
<br>
<table border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td valign="top"><font face="Courier New" size="2">Hi Alan, <br clear="none"><br clear="none">additional the sub can dynamic
unstable during surfacing.<br clear="none"> <br clear="none">There is a lot of water in the free
flooding open sail.<br clear="none">If you surface fast and with to small opening in the
<br clear="none">bottom of the free flooding sail the extra weight can <br clear="none">move
the CG so high that the sub tends to get heavy <br clear="none">side angles during
surfacing until the water rush out. <br clear="none"><br clear="none">The picture 8382a shows the
higher waterlevel during surfacing <br clear="none">in the sail and the MBT sadlle tanks
still under water <br clear="none">but for this sub the extra weight was not
critical.<br clear="none"><br clear="none">But on a military one with there tons of <br clear="none">water in the sail
during a fast emergency surfacing <br clear="none">it can be a problem. <br clear="none"><br clear="none">By the way
Euronaut has no Kingston valve without any problem<br clear="none">and a positve GB alltimes
greater than 2". <br clear="none">On dive station or surfaced. <br clear="none">And great openings in the
bottom of the sail. <br clear="none"><br clear="none">Boats without Kingston valve tends to lost some
<br clear="none">bouancy during rough sea. The tanks and the seastage<br clear="none">work like a air pump
and some water enter the tanks.<br clear="none"><br clear="none">On the otherside a boat with Kingston and
a <br clear="none">compressed air blow out system can blow away the <br clear="none">tanks very fast if
you forget to open the Kingstons <br clear="none">during blowing the tanks or have a air leak
<br clear="none">in the in the pipe to the tanks.<br clear="none"><br clear="none">vbr Carsten <br clear="none"> </font>
<br clear="none">
<br clear="none">"Alan James" <<a href="mailto:alanlindsayjames@yahoo.com">alanlindsayjames@yahoo.com</a>> schrieb:
<div class="yqt0464134751" id="yqt85816"><blockquote style="padding-right: 0px; padding-left: 5px; margin-right: 0px; margin-left: 5px; border-left-color: rgb(0, 0, 0); border-left-width: 2px; border-left-style: solid;">
<div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 14pt; background-color: rgb(255, 255, 255);">
<div></div>
<div id="yiv3971601525">
<div>
<div class="yui_3_13_0_ym1_1_1385770452280_2271" style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 14pt; background-color: rgb(255, 255, 255);">
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">Hi everyone,</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">While reading through some background info for the G.L.</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">certification document, I came across this link with a good</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">explanation of stability & buoyancy</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554"><a href="http://maritime.org/doc/fleetsub/chap5.htm" target="_blank" rel="nofollow" shape="rect">http://maritime.org/doc/fleetsub/chap5.htm</a><br clear="none"></div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">There is a phenomena described, where submarines can be </div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">unstable to the point of turning over during the transition from</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">surface to diving & vice versa.</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">This has to do with the centre of buoyancy moving upward past</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">the centre of gravity. As it approaches the centre of gravity the</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">submarine is at it's most vulnerable point.</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">This would be different for individual designs & a worry
if</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">you dropped your emergency drop weight.</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">I had been told by a pilot that he never stuffed around while</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">descending & liked to drop as quick as he could.</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">I didn't have a full understanding of this & thought there may</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">be others in the same boat.</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554">Regards Alan</div>
<div id="yiv3971601525yui_3_13_0_ym1_1_1385768974238_2554"><br clear="none"></div>
</div>
</div>
</div>
<span></span>
<div></div>
</div>
</blockquote></div>
<font face="Courier New" size="2"> </font><font face="Courier New" size="2"><br clear="none"><br clear="none">-- <br clear="none"><br clear="none">Carsten Standfuß<br clear="none">Dipl.Ing.Schiffbau @ Meerestechnik<br clear="none">Heinrich Reck Str.12A<br clear="none">18211 Admannshagen<br clear="none"><br clear="none">0172 8464 420<br clear="none"><a href="http://WWW.Euronaut.org" target="_blank">WWW.Euronaut.org</a><br clear="none"><a href="mailto:Carsten@euronaut.org">Carsten@euronaut.org</a></font></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</div>
<div id="AOLMsgPart_3_e7deb527-2687-41cf-a31b-096c4f8c2a3d" style="margin: 0px; color: rgb(0, 0, 0); font-family: Tahoma, Verdana, Arial, Sans-Serif; font-size: 12px; background-color: rgb(255, 255, 255);">
<pre style="font-size: 9pt;"><tt>_______________________________________________
Personal_Submersibles mailing list
<a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a>
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a>
</tt></pre>
</div>
<!-- end of AOLMsgPart_3_e7deb527-2687-41cf-a31b-096c4f8c2a3d -->
</div>
</font>