<table cellspacing="0" cellpadding="0" border="0"><tr><td valign="top">Alan,<br/><br/>Very helpful, particularly with regard to failure modes and stability. The single MBT failure mode of particular interest.<br/><br/>I can do stability calcs on various angles of heel for a contiguous hull form, but I still have to study odd shaped underwater sections like a K-350.<br/><br/>Interesting stuff!<br/><br/>Joe<a href="http://overview.mail.yahoo.com?.src=iOS"><br/><br/>Sent from Yahoo Mail for iPad</a></td></tr></table> <div id="_origMsg_">
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<span style="font-weight:bold">From:</span>
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Alan James <alanlindsayjames@yahoo.com>; <br>
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<span style="font-weight:bold">To:</span>
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psubs.org <personal_submersibles@psubs.org>; <br>
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<span style="font-weight:bold">Subject:</span>
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[PSUBS-MAILIST] G.L. Summary Stability & Buoyancy <br>
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<span style="font-weight:bold">Sent:</span>
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Thu, Dec 5, 2013 9:08:25 AM <br>
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<td valign="top"><div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:14pt;"><div id="yiv7320916847"><div><div style="color:rgb(0, 0, 0);background-color:rgb(255, 255, 255);font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:14pt;"><div id="yiv7320916847"><div id="yiv7320916847yui_3_13_0_ym1_1_1386136859721_2431"><div style="color:rgb(0, 0, 0);background-color:rgb(255, 255, 255);font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:14pt;" class="yiv7320916847yui_3_13_0_ym1_1_1386136859721_2403" id="yiv7320916847yui_3_13_0_ym1_1_1386136859721_2430"><div id="yiv7320916847"><div id="yiv7320916847yui_3_13_0_ym1_1_1386065276172_2456"><div style="color:rgb(0, 0, 0);background-color:rgb(255, 255, 255);font-family:HelveticaNeue, 'Helvetica
Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:14pt;" class="yiv7320916847yui_3_13_0_ym1_1_1386065276172_2397 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2404" id="yiv7320916847yui_3_13_0_ym1_1_1386065276172_2455"><div id="yiv7320916847"><div id="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2441"><div style="color:rgb(0, 0, 0);background-color:rgb(255, 255, 255);font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:14pt;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2362 yiv7320916847yui_3_13_0_ym1_1_1386065276172_2398 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2405" id="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2440"><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502"><br></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502">I'm afraid there is nothing simple in this section. It is lacking in a lot of specifics.</div><div
id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502">There
are statements such as "shall generally meet the standard
defined</div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502">in the following unless special operational restrictions reflected in the class</div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502">notification allow a lower level. & ...Depending on the type of submersible & the </div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502">operation area, the distance
between the waterline in fully surfaced condition</div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502">and the upper edge of entrance openings, air pipes,etc. which may be open</div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502">for surfaced operation, has to be approved by G.L.</div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502"> ABS has a minimum distance from the waterline to the hatch opening of 30"</div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502">whereas G.L. states; <span style="font-size:14pt;">For
surfaced; </span><span id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_3357" style="font-size:14pt;">a minimum </span><span id="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2486" style="background-color:transparent;font-size:14pt;">distance between metacentric height & center of gravity </span><span id="yiv7320916847yui_3_13_0_ym1_7_1386063901473_17" style="background-color:transparent;font-size:14pt;">of 10cm. (4") </span><span id="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2596" style="background-color:transparent;font-size:14pt;">And for submerged, a minimum distance between center of buoyancy </span><span id="yiv7320916847yui_3_13_0_ym1_7_1386063901473_21" style="background-color:transparent;font-size:14pt;">& center </span><span id="yiv7320916847yui_3_13_0_ym1_1_1386065276172_2496" style="background-color:transparent;font-size:14pt;">of gravity of 5cm (2") (same as ABS). At no stage will G be
above B. (including after dropping the drop weight)</span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370 yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2414"><span style="font-size:14pt;" id="yiv7320916847yui_3_13_0_ym1_7_1386061802447_54">In the initial paper work sent before construction, a detailed analyses of stability is to</span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416"><span style="font-size:14pt;" id="yiv7320916847yui_3_13_0_ym1_7_1386065276172_24">be </span><span style="font-size:14pt;background-color:transparent;" id="yiv7320916847yui_3_13_0_ym1_1_1386065276172_3315">included. This takes the form of analyzing the heeling levers of 10 different load cases in fresh & salt water, 6 </span><span style="background-color:transparent;font-size:14pt;">on the surface & 4 submerged & at 6 different heeling</span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;">angles. So looks like 120 calculations. </span><span style="background-color:transparent;font-size:14pt;">Heeling forces from free liquid surfaces, turning circles, wind, ice loads, transference </span><span style="background-color:transparent;font-size:14pt;">of equipment & personal & payloads from working devices have to be considered.</span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;">There needs to be sufficient ballast to keep a minimum of 10% of the pressure</span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;">hull out of the water. The draught line has to be marked on the hull. </span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;">When one major ballast tank is damaged the hatch has to be able to open without</span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;">water coming in & the heeling angle shouldn't exceed 22,5 degrees.</span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;">There is an operational in water test at the end of construction with evaluation</span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;">of the center of gravity upon which the pre build calculations were based.</span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;">Alan</span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;"><br></span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;"><br></span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="background-color:transparent;font-size:14pt;"><br></span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><br></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502" style="color:rgb(0, 0, 0);font-size:14pt;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;background-color:transparent;font-style:normal;" class="yiv7320916847yui_3_13_0_ym1_1_1386063901473_2370
yiv7320916847yui_3_13_0_ym1_1_1386065276172_2405 yiv7320916847yui_3_13_0_ym1_1_1386136859721_2416 yui_3_13_0_ym1_1_1386231496534_2369"><span style="font-size:14pt;background-color:transparent;"><br></span></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502"><br></div><div id="yiv7320916847yui_3_13_0_ym1_1_1386061802447_2502"><br></div></div></div></div></div></div></div></div></div></div></div></div></div></div></td>
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