<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Thanks Carsten,</div><div>I hadn't thought of the water in a sail.</div><div>Good picture.</div><div>Alan<br><br>Sent from my iPad</div><div><br>On 30/11/2013, at 11:51 PM, " " <<a href="mailto:MerlinSub@t-online.de">MerlinSub@t-online.de</a>> wrote:<br><br></div><blockquote type="cite"><div>
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<font face="Courier New" size="2">Hi Alan, <br><br>additional the sub can dynamic
unstable during surfacing.<br> <br>There is a lot of water in the free
flooding open sail.<br>If you surface fast and with to small opening in the
<br>bottom of the free flooding sail the extra weight can <br>move
the CG so high that the sub tends to get heavy <br>side angles during
surfacing until the water rush out. <br><br>The picture 8382a shows the
higher waterlevel during surfacing <br>in the sail and the MBT sadlle tanks
still under water <br>but for this sub the extra weight was not
critical.<br><br>But on a military one with there tons of <br>water in the sail
during a fast emergency surfacing <br>it can be a problem. <br><br>By the way
Euronaut has no Kingston valve without any problem<br>and a positve GB alltimes
greater than 2". <br>On dive station or surfaced. <br>And great openings in the
bottom of the sail. <br><br>Boats without Kingston valve tends to lost some
<br>bouancy during rough sea. The tanks and the seastage<br>work like a air pump
and some water enter the tanks.<br><br>On the otherside a boat with Kingston and
a <br>compressed air blow out system can blow away the <br>tanks very fast if
you forget to open the Kingstons <br>during blowing the tanks or have a air leak
<br>in the in the pipe to the tanks.<br><br>vbr Carsten <br> </font>
<br>
<br>"Alan James" <<a href="mailto:alanlindsayjames@yahoo.com">alanlindsayjames@yahoo.com</a>> schrieb:
<blockquote style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<div style="FONT-SIZE: 14pt; COLOR: #000; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; BACKGROUND-COLOR: #fff"><div></div><div id="yiv3971601525"><div><div style="FONT-SIZE: 14pt; COLOR: #000; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; BACKGROUND-COLOR: #fff" class="yui_3_13_0_ym1_1_1385770452280_2271"><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">http://maritime.org/doc/fleetsub/chap5.htm</a><br></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></div></div></div></div><span></span><div></div></div>
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<font face="Courier New" size="2"> </font><font face="Courier New" size="2"><br><br>-- <br><br>Carsten Standfuß<br>Dipl.Ing.Schiffbau @ Meerestechnik<br>Heinrich Reck Str.12A<br>18211 Admannshagen<br><br>0172 8464 420<br><a href="http://WWW.Euronaut.org">WWW.Euronaut.org</a><br><a href="mailto:Carsten@euronaut.org">Carsten@euronaut.org</a></font>
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