<html><head></head><body><div style="color:#000; background-color:#fff; font-family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:13px"><div><span>Hi Alec,</span></div><div id="yui_3_16_0_ym19_1_1492161521339_8902"><span>Congratulations !! your issues are pretty minor in the grand scheme of things. The problem with the venting is suspicious to me. If the vent tubes do not have water in them, they should still vent air, even if they are below the water line because the weight of the sub is creating </span>pressure inside the tank witch will force the air down hill so to speak. I was not there to see it of coarse, so I could be out to lunch. From what you describe, changing the lines may not do it, I think you will need individual valves, not per tank but per side. </div><div dir="ltr" id="yui_3_16_0_ym19_1_1492161521339_8900">I had a similar problem with Gamma, but in reverse. When I surfaced the sub would list to one side badly because I have a common vent for the front and back. Ideally you want front and back and side to side. I corrected this by putting extension tubes on the bottom of the ballast tank vents, this forces the water level to self balance because one tank will not vent air out the bottom until the sub is level.</div><div dir="ltr" id="yui_3_16_0_ym19_1_1492161521339_8900">It sounds to me like you have a similar situation. If you have the ability to control venting from side to side, you will also avoid the problem I had, and I suspect may still show up. Your big tall CT could create this effect while transitioning.</div><div dir="ltr" id="yui_3_16_0_ym19_1_1492161521339_8900"><br></div><div dir="ltr" id="yui_3_16_0_ym19_1_1492161521339_8900"><br></div><div dir="ltr" id="yui_3_16_0_ym19_1_1492161521339_8900"><br></div><div dir="ltr" id="yui_3_16_0_ym19_1_1492161521339_8900">Hank</div><div dir="ltr" id="yui_3_16_0_ym19_1_1492161521339_8900"><br></div> <div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 13px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"><font size="2" face="Arial"> On Thursday, April 13, 2017 8:45 PM, Alec Smyth via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br></font></div> <br><br> <div class="y_msg_container"><div id="yiv8386865782"><div><div dir="ltr">Hi Greg,<div><br clear="none"></div><div>Well here's how it went - much better but there's one more issue to resolve. </div><div><br clear="none"></div><div>The change to a raft configuration for the MBTs has solved the surfaced stability issue. It was great, I could walk around to any edge of the deck without excessive list. The longitudinal trim was slightly down by the stern when empty, and trimmed out to perfectly level when a person was lying in the front half of the boat (stability was calculated for the boat with crew). She floats in water only just over waist deep, 38 inches, and the freeboard is 24 inches. The thrusters and their controls worked beautifully, and the "tank drive" is really, really intuitive. </div><div><br clear="none"></div><div>After launching I drove around on the surface a bit. I didn't get a measurement of speed but would say while slower than a K350 she's decidedly faster than Snoopy. I tested a prototype kort nozzle by mounting it on one of the stern thrusters only and then giving both thrusters equal throttle, to see which way the boat tracked. Surprise, the un-shrouded original prop was more efficient because the boat would turn toward the side with the kort. So I'm just going to put on standard prop guards, at least for now.</div><div><br clear="none"></div><div>Part of the surface running I did lying down and looking through the bow dome. The view is ridiculously good! From the CT it wasn't bad either, and I was surprised how the flat domes made objects appear closer, something I didn't recall from the flat bow dome in Snoopy. In this one, the leading edge of the deck as seen through the CT viewports seemed only a foot away. The dome is something else entirely, and optically seemed to have the opposite effect of making things appear further away, but maybe that was just in contrast to the CT viewports I'd been looking though moments before.</div><div><br clear="none"></div><div>And so here is the new problem. The raft MBT consists of a collection of aluminum tanks, each of which has SS tubing coming out the top and gathering at a manifold, which is piped to the ball valves on the CT. As some of the tanks are off on the edges of the raft, some of the tubing runs side to side at an angle (up to 90 degrees) to the centerline. When you start flooding MBT, invariably one side will begin to fill slightly faster than the other. The side that is flooding faster will be lower in the water, and the effect of this list on the opposite side is that the tube connecting tanks to their manifold is now sloping downhill instead of up. This blocks the high side from letting out air, which exacerbates the initial list. It's really obvious when you see it, I should have thought of this effect. But luckily the solution is obvious too. There are two ways to fix it; remotely actuated valves right on the tanks, or new manifolds that are high enough to keep all tubing going uphill at reasonable angles of list. My initial impression is that the simpler of the two methods is to modify the plumbing. </div><div><br clear="none"></div><div><br clear="none"></div><div>Best,</div><div><br clear="none">Alec</div><div><br clear="none"></div><div><br clear="none"></div><div><br clear="none"></div><div><br clear="none"></div></div><div class="yiv8386865782gmail_extra"><br clear="none"><div class="yiv8386865782gmail_quote">On Thu, Apr 13, 2017 at 10:10 PM, james cottrell via Personal_Submersibles <span dir="ltr"><<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span> wrote:<br clear="none"><blockquote class="yiv8386865782gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div class="yiv8386865782yqt8106051098" id="yiv8386865782yqt55091"><div><div style="color:#000;background-color:#fff;font-family:verdana, helvetica, sans-serif;font-size:13px;"><div><span></span></div><div class="yiv8386865782m_-2889796519550700373qtdSeparateBR" id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10055">Did anyone hear how Alec's test went today?<br clear="none"><br clear="none"></div><div class="yiv8386865782m_-2889796519550700373yahoo_quoted" id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10076" style="display:block;"> <div id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10075" style="font-family:verdana, helvetica, sans-serif;font-size:13px;"> <div id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10074" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div dir="ltr" id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10073"> <font id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10072" face="Arial" size="2"> </font><hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Alan via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs. org</a>><br clear="none"> <b><span style="font-weight:bold;">To:</span></b> Personal Submersibles General Discussion <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs. org</a>> <br clear="none"> <b><span style="font-weight:bold;">Sent:</span></b> Thursday, April 13, 2017 9:34 PM<br clear="none"> <b><span style="font-weight:bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Oil Compensator<br clear="none"> </div> <div class="yiv8386865782m_-2889796519550700373y_msg_container" id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10078"><br clear="none"><div id="yiv8386865782m_-2889796519550700373yiv7198155306"><div id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10077"><div>Jon,</div><div id="yiv8386865782m_-2889796519550700373yiv7198155306AppleMailSignature">an easy solution is to take the thruster, or that section of the thruster</div><div id="yiv8386865782m_-2889796519550700373yiv7198155306AppleMailSignature">in to a plumbing merchant or hydraulic repair shop & ask for something </div><div id="yiv8386865782m_-2889796519550700373yiv7198155306AppleMailSignature">compatible with a barbed hose fitting. Sometimes a metric option will</div><div id="yiv8386865782m_-2889796519550700373yiv7198155306AppleMailSignature">fit in an imperial thread, & so they may know of not so obvious solutions.</div><div id="yiv8386865782m_-2889796519550700373yiv7198155306AppleMailSignature">Alan<br clear="none"><br clear="none">Sent from my iPad</div><div class="yiv8386865782m_-2889796519550700373yiv7198155306yqt0765085698" id="yiv8386865782m_-2889796519550700373yiv7198155306yqt69176"><div id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10079"><br clear="none">On 14/04/2017, at 12:53 PM, Jon Wallace via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs. org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10082" type="cite"><div id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10081"><div id="yiv8386865782m_-2889796519550700373yui_3_16_0_ym19_1_1492135216136_10080" style="color:rgb(0,0,0);font-family:times new roman, new york, times, serif;font-size:16px;background-color:rgb(255,255,255);"><div dir="ltr" id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3496"><span>Hi Hank,</span></div><div dir="ltr" id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3496"><span><br clear="none"></span></div><div dir="ltr" id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3496"><span id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3592">No, I don't have the shaft, I purchased just the lower head. A 36 inch shaft is $28 but like you said, I really only need a few inches of it so don't really want to purchase it that way.</span></div><div dir="ltr" id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3496"><span><br clear="none"></span></div><div dir="ltr" id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3496"><span>Jon</span></div> <div class="yiv8386865782m_-2889796519550700373yiv7198155306qtdSeparateBR" id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3459"><br clear="none"><br clear="none"></div><div class="yiv8386865782m_-2889796519550700373yiv7198155306yahoo_quoted" id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3451" style="display:block;"> <div id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3450" style="font-family:times new roman, new york, times, serif;font-size:16px;"> <div id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3449" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div dir="ltr" id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3458"><font id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3457" face="Arial" size="2"> On Thursday, April 13, 2017 8:27 PM, hank pronk via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs. org</a>> wrote:<br clear="none"></font></div> <br clear="none"><br clear="none"> <div class="yiv8386865782m_-2889796519550700373yiv7198155306y_msg_container" id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3448"><div id="yiv8386865782m_-2889796519550700373yiv7198155306"><div id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3447"><div id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3446" style="color:rgb(0,0,0);font-family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:13px;background-color:rgb(255,255,255);"><div id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3455"><span id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3456">Jon, </span></div><div id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3454"><span id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3453">Do you have the shaft that used to screw into the motor? if so, you can cut it down to a couple inches long and put a waterline compression fitting on that. Then reduce from the compression pipe thread. Or you can thread the inside of that stub shaft with a pipe tap and reduce from that, providing it is the heave fibreglass shaft.</span></div><div id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3452"><span>Hank</span></div> <div class="yiv8386865782m_-2889796519550700373yiv7198155306qtdSeparateBR" id="yiv8386865782m_-2889796519550700373yiv7198155306yui_3_16_0_ym19_1_1492131028055_3445"><br clear="none"><br clear="none"></div></div></div></div></div> </div> </div> </div></div></div></blockquote></div><blockquote type="cite"><div><span>______________________________ _________________</span><br clear="none"><span>Personal_Submersibles mailing list</span><br clear="none"><span><a rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" target="_blank" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs. org</a></span><br clear="none"><span><a rel="nofollow" shape="rect" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/ listinfo.cgi/personal_ submersibles</a></span><br clear="none"></div></blockquote></div></div><div class="yiv8386865782m_-2889796519550700373yqt0765085698" id="yiv8386865782m_-2889796519550700373yqt26092">______________________________ _________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" target="_blank" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs. org</a><br clear="none"><a rel="nofollow" shape="rect" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/ listinfo.cgi/personal_ submersibles</a><br clear="none"></div><br clear="none"><br clear="none"></div> </div> </div> </div></div></div></div><br clear="none">______________________________ _________________<br clear="none">
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