<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_ym19_1_1479007606283_2431"><span>Hank,</span></div><div id="yui_3_16_0_ym19_1_1479007606283_2512"><span id="yui_3_16_0_ym19_1_1479007606283_2511">GL says in Section 7 Arrangement for Diving/Ballasting, Control/Compensating & Trimming....</span></div><div id="yui_3_16_0_ym19_1_1479007606283_2514"><span id="yui_3_16_0_ym19_1_1479007606283_2513">In the event of the failure of the compensating tank system, the submersible shall be capable</span></div><div id="yui_3_16_0_ym19_1_1479007606283_2674" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_2680">of surfacing by jettisoning of ballast & or emergency blowing of the diving tanks, & has to float</span></div><div id="yui_3_16_0_ym19_1_1479007606283_2724" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_2726">on the surface in an upright stable position.</span></div><div id="yui_3_16_0_ym19_1_1479007606283_2727" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3214">Section 15 Rescue system, 3.1 .... Mathematical proof is to be furnished that, after release of</span></div><div id="yui_3_16_0_ym19_1_1479007606283_2875" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3017">the solid ballast the submersible rises safely to the surface & floats there in a stable position.</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3039" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3110"> They stipulate elsewhere that you have to have a drop weight; but from section</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3109" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3108">7 it seems that it is there only to cover a failure of the compensating tank. I assume the compensating</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3112" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3111">tank is a hard tank. So you would need enough ballast in your drop weight to cover the full </span></div><div id="yui_3_16_0_ym19_1_1479007606283_3114" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3113">condition of your compensating tank. This seems a bit funny because your air for blowing your</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3181" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3180">tanks has to be enough to cover the event of any major failure of a cavity such as the battery</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3176" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3175">pod. You would think that this air might also suffice for the compensating tank failure.</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3179" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3178"> So as long as you have enough to cover that, & don't turn upside down on the surface or way up,</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3177" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3209">ie. your centre of buoyancy is still above your center of gravity, you should be right.</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3254" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3253"> According to section 7 it seems that as long as there is enough compressed air to compensate for any of these</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3255" dir="ltr"><span id="yui_3_16_0_ym19_1_1479007606283_3353">failures at your dive depth, then you would need very little weight. I say very little because</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3354" dir="ltr"><span>of the rule that you need a drop weight. :)</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3395" dir="ltr"><span>Let me know if it is not making sense.</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3396" dir="ltr"><span>Alan</span></div><div id="yui_3_16_0_ym19_1_1479007606283_3338" dir="ltr"><span></span> </div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1479007606283_2515"><br><br></div><div class="yahoo_quoted" id="yui_3_16_0_ym19_1_1479007606283_2678" style="display: block;"> <div id="yui_3_16_0_ym19_1_1479007606283_2677" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym19_1_1479007606283_2676" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym19_1_1479007606283_2675" dir="ltr"> <font id="yui_3_16_0_ym19_1_1479007606283_2679" face="Arial" size="2"> <hr size="1" id="yui_3_16_0_ym19_1_1479007606283_2745"> <b><span style="font-weight: bold;">From:</span></b> hank pronk via Personal_Submersibles <personal_submersibles@psubs.org><br> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br> <b id="yui_3_16_0_ym19_1_1479007606283_3041"><span id="yui_3_16_0_ym19_1_1479007606283_3040" style="font-weight: bold;">Sent:</span></b> Sunday, November 13, 2016 2:45 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> [PSUBS-MAILIST] drop weight<br> </font> </div> <div class="y_msg_container"><br><div id="yiv1354825615"><div><div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12px; background-color: rgb(255, 255, 255);"><div id="yiv1354825615yui_3_16_0_ym19_1_1479001374322_5258">Can someone tell me what the proper weight of a drop weight is. There must be a rule.</div><div id="yiv1354825615yui_3_16_0_ym19_1_1479001374322_5258">Hank</div></div></div></div><br>_______________________________________________<br>Personal_Submersibles mailing list<br><a href="mailto:Personal_Submersibles@psubs.org" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br><br><br></div> </div> </div> </div></div></body></html>