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<div><br></div><div dir="ltr" data-setdir="false">Brian ,</div><div dir="ltr" data-setdir="false">Well done! each time you go out now it will get better. You seem real heavy though in the back. Man that dives fast, almost as fast as Alec.</div><div dir="ltr" data-setdir="false">Hank</div>
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On Wednesday, August 26, 2020, 11:40:42 AM MDT, Brian Cox via Personal_Submersibles <personal_submersibles@psubs.org> wrote:
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<div><div id="yiv8999362452"><div><div style="font-family:Arial, sans-serif;font-size:10pt;"><font size="2" style=""><font face="Arial, sans-serif">I'm venting with a 2" ball valve , so I can just crack it if I want to minimize the vent rate. In this case I wanted to get through a slight list quickly. I'm just going to keep putting more buoyancy in front until that nose stays up. </font></font><div><font size="2" style=""><font face="Arial, sans-serif"><br clear="none"></font></font></div><div><font size="2" style=""><font face="Arial, sans-serif">Brian</font></font></div><div><font size="2" style=""><font face="Arial, sans-serif"><br clear="none"></font></font></div><div><font size="2" style=""><font face="Arial, sans-serif"> </font></font><br clear="none"><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">--- personal_submersibles@psubs.org wrote:</span><br clear="none"><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">From: Cliff Redus via Personal_Submersibles <personal_submersibles@psubs.org></span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">To: Brian Cox via Personal_Submersibles <personal_submersibles@psubs.org></span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Subject: Re: [PSUBS-MAILIST] Sub Launch at Harbor</span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Date: Wed, 26 Aug 2020 17:26:07 +0000 (UTC)</span><br clear="none"><br clear="none"><div style="font-family:new times, serif;font-size:16px;"><div></div>
<div dir="ltr">If you are ballasted correctly for submerged operations so that the boat stabilizes to a horizontal attitude when the MBT is completely flooded, then reducing the orifice size on the forward MBT vent opening will reduce this pitching moment when submerging. On my boat, I made up a series of pipe plugs that would screw into my forward and aft MBT vent openings. I then did a series of MBT flood test to see which orifice sizes nulled out this pitching moment. It worked great. The other way to solve the problem is what Alec did my installing Hugh Fulton's MBT vent valves which have a very large opening. In this case the boat submerges so fast there is no time for this pitching moment to act on the boat.</div><div dir="ltr"><br clear="none"></div><div dir="ltr">Best</div><div dir="ltr"><br clear="none"></div><div dir="ltr"><br clear="none"></div><div><br clear="none"></div>
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On Wednesday, August 26, 2020, 12:13:35 PM CDT, Brian Cox via Personal_Submersibles <personal_submersibles@psubs.org> wrote:
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<div><div><div><div style="font-family:Arial, sans-serif;font-size:10pt;"><font size="2"><font face="Arial, sans-serif">Cliff, I think that would only delay the inevitable , I think I would still be at the same angle.</font></font><div><font face="Arial, sans-serif" size="2"><br clear="none"></font></div><div><font face="Arial, sans-serif" size="2">Brian</font></div><div><font face="Arial, sans-serif" size="2"><br clear="none"></font></div><div><font face="Arial, sans-serif" size="2"><br clear="none"></font><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">--- personal_submersibles@psubs.org wrote:</span><br clear="none"><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">From: Cliff Redus via Personal_Submersibles <personal_submersibles@psubs.org></span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">To: Brian Cox via Personal_Submersibles <personal_submersibles@psubs.org></span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Subject: Re: [PSUBS-MAILIST] Sub Launch at Harbor</span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Date: Wed, 26 Aug 2020 16:44:48 +0000 (UTC)</span><br clear="none"><br clear="none"><div style="font-family:new times, serif;font-size:16px;"><div></div>
<div dir="ltr">Congratulations on the successful surface maneuvering test and dive. You might want to experiment with different orifice inserts in the forward MBT vent opening to see if you can reduce the pitching moment when flooding by reducing the flowrate of air out of this tank. I use this technique on the R300 for the same purpose.</div><div dir="ltr"><br clear="none"></div><div dir="ltr">Cliff</div><div dir="ltr"><br clear="none"></div><div dir="ltr"><br clear="none"></div><div><br clear="none"></div>
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On Wednesday, August 26, 2020, 11:27:53 AM CDT, Brian Cox via Personal_Submersibles <personal_submersibles@psubs.org> wrote:
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<div><div><div><div style="font-family:Arial, sans-serif;font-size:10pt;"><font size="2" style="font-family:Arial, sans-serif;">Yeah, that's my super secret emergency dive </font><font face="Arial, sans-serif" size="2">procedure !</font><div><font face="Arial, sans-serif" size="2"><br clear="none"></font></div><div><font face="Arial, sans-serif" size="2">Brian</font></div><div><font face="Arial, sans-serif" size="2"><br clear="none"></font></div><div><font face="Arial, sans-serif" size="2"><br clear="none"></font><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">--- personal_submersibles@psubs.org wrote:</span><br clear="none"><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">From: Alec Smyth via Personal_Submersibles <personal_submersibles@psubs.org></span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">To: Personal Submersibles General Discussion <personal_submersibles@psubs.org></span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Subject: Re: [PSUBS-MAILIST] Sub Launch at Harbor</span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Date: Wed, 26 Aug 2020 12:03:20 -0400</span><br clear="none"><br clear="none"><div dir="ltr" style="font-family:Arial, sans-serif;font-size:10pt;">Hey, that wasn't a launch, it was a dive!! Congrats! When the bow went down like that, did it rest on the bottom? That was a pretty radical angle, and the speed of it makes me think you had a massive free surface displacement in the MBT. Normally that induces lateral instability, but due to the length of your boat in this case it would be longitudinal instability.<div><br clear="none"></div><div>Thanks,</div><div>Alec</div></div><br clear="none"><div style="font-family:Arial, sans-serif;font-size:10pt;"><div><div dir="ltr">On Wed, Aug 26, 2020 at 10:44 AM Brian Cox 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"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;"><div style="font-family:Arial, sans-serif;font-size:10pt;"><font size="2">Hi All, </font><div><font size="2"> Have a couple of videos from down at the harbor:</font></div><div><font size="2"><br clear="none"></font></div><div><font size="2"><br clear="none"></font></div><div><font size="2"><a rel="nofollow" shape="rect" target="_blank" href="https://www.youtube.com/watch?v=iERfLiioGJA&t=628s">https://www.youtube.com/watch?v=iERfLiioGJA&t=628s</a><br clear="none"></font></div><div><br clear="none"></div><div><br clear="none"></div><div><br clear="none"></div><div><a rel="nofollow" shape="rect" target="_blank" href="https://www.youtube.com/watch?v=OGiAqeocq4s">https://www.youtube.com/watch?v=OGiAqeocq4s</a><br clear="none"></div><div><br clear="none"></div><div><br clear="none"></div><div>Cheers,</div><div><br clear="none"></div><div>Brian</div><div><br clear="none"></div><div><br clear="none"></div></div>
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