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<div dir="ltr" data-setdir="false">Brian,</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">I have a pressure compensation calculator on the website. Enter max depth, length of your tube, and it will tell you the air gap at that depth (seawater). <span><a href="http://www.psubs.org/design/calcs/ocpt.html" rel="nofollow" target="_blank" class="enhancr_card_5878056191">PSUBS.ORG</a></span><div><br></div><div id="ydp7d9de059enhancr_card_5878056191" class="ydp7d9de059yahoo-link-enhancr-card ydp7d9de059yahoo-link-enhancr-not-allow-cover ydp7d9de059ymail-preserve-class ydp7d9de059ymail-preserve-style" style="max-width:400px;font-family:Helvetica Neue, Segoe UI, Helvetica, Arial, sans-serif" data-url="http://www.psubs.org/design/calcs/ocpt.html" data-type="YENHANCER" data-size="MEDIUM" contenteditable="false"><a href="http://www.psubs.org/design/calcs/ocpt.html" style="text-decoration:none !important;color:#000 !important" class="ydp7d9de059yahoo-enhancr-cardlink" rel="nofollow" target="_blank"><table border="0" class="ydp7d9de059card-wrapper ydp7d9de059yahoo-ignore-table" cellpadding="0" cellspacing="0" style="max-width:400px"><tbody><tr><td width="400"><table border="0" class="ydp7d9de059card ydp7d9de059yahoo-ignore-table" cellpadding="0" cellspacing="0" width="100%" style="max-width:400px;border-width:1px;border-style:solid;border-color:rgb(224, 228, 233);border-radius:2px"><tbody><tr><td><table border="0" class="ydp7d9de059card-info ydp7d9de059yahoo-ignore-table" cellpadding="0" cellspacing="0" style="background:#fff;position:relative;z-index:2;width:100%;max-width:400px;border-radius:0 0 2px 2px;border-top:1px solid rgb(224, 228, 233)"><tbody><tr><td style="background-color:#ffffff;padding:16px 0 16px 12px;vertical-align:top;border-radius:0 0 0 2px"></td><td style="vertical-align:middle;padding:12px 24px 16px 12px;width:99%;font-family:Helvetica Neue, Segoe UI, Helvetica, Arial, sans-serif;border-radius:0 0 2px 0"><h2 class="ydp7d9de059card-title" style="font-size: 14px; line-height: 19px; margin: 0px 0px 6px; font-family: Helvetica Neue, Segoe UI, Helvetica, Arial, sans-serif; color: rgb(38, 40, 42); max-width: 314px;">PSUBS.ORG</h2><p class="ydp7d9de059card-description" style="font-size: 12px; line-height: 16px; margin: 0px; color: rgb(151, 155, 167);"></p></td></tr></tbody></table></td></tr></tbody></table></td></tr></tbody></table></a></div><div><br></div><div><br></div></div><div><br></div>
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On Wednesday, March 25, 2020, 11:17:07 AM EDT, Brian Cox via Personal_Submersibles <personal_submersibles@psubs.org> wrote:
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<div><div id="ydped19d2e5yiv2200305111"><div><div style="font-family:Arial, sans-serif;font-size:10pt;"><font size="2" style="font-family:Arial, sans-serif;">Alan,</font><div><font size="2"><font face="Arial, sans-serif"> Yes I did think about that condition , the drawback with having a large reservoir is that there is that much more air to compress. I was going to have a plug in the bottom of the 3" pvc so I could drain it out if I did get some water in there or if there was water and oil. What I need to do is to just calculate the total volume of air and see how much water would fill the reservoir at maximum depth. As long as the reservoir does not completely fill then there's no way water can get to the motor. Theoretically you could squeeze the air down to nothing in the reservoir. </font></font></div><div><font size="2"><font face="Arial, sans-serif"><br clear="none"></font></font></div><div><font size="2"><font face="Arial, sans-serif">Hank, oh the stories I could tell you about transferring honey ( listen David !) pouring 55 gallons of cold honey into a 5 gallon pail, not being one who wants to waist time, I couldn't just sit there doing nothing for a half an hour so I naturally found a small project to do . Then getting involved with what ever I was doing - you can guess the rest , honey is very quiet when it's draining all over your shop floor 55 gallons into every nook and cranny you can imagine ! unfortunately this happened more than once ! </font></font></div><div><font size="2"><font face="Arial, sans-serif"><br clear="none"></font></font></div><div><font size="2"><font face="Arial, sans-serif"><br clear="none"></font></font></div><div><font size="2"><font face="Arial, sans-serif">Brian</font></font></div><div><font size="2"><font face="Arial, sans-serif"><br clear="none"></font></font></div><div><font size="2"><font face="Arial, sans-serif"><br clear="none"></font></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: Alan 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] motor oil compensator</span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Date: Wed, 25 Mar 2020 21:42:08 +1300</span><br clear="none"><br clear="none"><div style="font-family:Arial, sans-serif;font-size:10pt;"></div><div style="font-family:Arial, sans-serif;font-size:10pt;">Brian,</div><div style="font-family:Arial, sans-serif;font-size:10pt;">not sure of your depth but if you are going to 300ft, the air will be compressed to</div><div style="font-family:Arial, sans-serif;font-size:10pt;">1/12th the volume, so the oil overflow reservoir is going to be problematic because</div><div style="font-family:Arial, sans-serif;font-size:10pt;">It's large volume could mean the seawater would come a long way up the tube on</div><div style="font-family:Arial, sans-serif;font-size:10pt;">the seaward side. Also using it as an overflow would create the problem of "how do </div><div style="font-family:Arial, sans-serif;font-size:10pt;">I get the oil back in the motor" & " how do I monitor it".</div><div style="font-family:Arial, sans-serif;font-size:10pt;">I have had rubber perish in WD40 so I would watch that if you are considering using</div><div style="font-family:Arial, sans-serif;font-size:10pt;">a rubber compensator.</div><div style="font-family:Arial, sans-serif;font-size:10pt;">Have a look at the PDF I referenced as that has several options.</div><div style="font-family:Arial, sans-serif;font-size:10pt;">Alan</div><div style="font-family:Arial, sans-serif;font-size:10pt;"><br clear="none"></div><div style="font-family:Arial, sans-serif;font-size:10pt;"><br clear="none"></div><div class="ydped19d2e5yiv2200305111yqt9701155013" id="ydped19d2e5yiv2200305111yqt07470"><div style="font-family:Arial, sans-serif;font-size:10pt;"><br clear="none">On 25/03/2020, at 5:40 PM, Brian Cox via Personal_Submersibles <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote style="font-family:Arial, sans-serif;font-size:10pt;"><div><div style="font-family:Arial, sans-serif;font-size:10pt;"><font size="2" style="font-family:Arial, sans-serif;">Alan, </font><div><font size="2"><font face="Arial, sans-serif"> So do you see any issues with the way I have my compensator set up? I've been trying to see a scenario where it wouldn't work, but I don't see one. One reason I like it is because there in no over or under pressure in the system.</font></font></div><div><font size="2"><font face="Arial, sans-serif"><br clear="none"></font></font></div><div><font size="2"><font face="Arial, sans-serif">Brian</font></font></div><div><font size="2"><font face="Arial, sans-serif"><br clear="none"></font></font></div><div><font size="2"><font face="Arial, sans-serif"> </font><br clear="none"></font><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">--- <a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a> wrote:</span><br clear="none"><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">From: Alan via Personal_Submersibles <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>></span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">To: Personal Submersibles General Discussion <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>></span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Subject: Re: [PSUBS-MAILIST] motor oil compensator</span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Date: Wed, 25 Mar 2020 17:28:21 +1300</span><br clear="none"><br clear="none"><div style="font-family:Arial, sans-serif;font-size:10pt;"></div><div style="font-family:Arial, sans-serif;font-size:10pt;">Brian,</div><div style="font-family:Arial, sans-serif;font-size:10pt;">I wouldn't read a lot in to that experiment as far as heating goes, as when</div><div style="font-family:Arial, sans-serif;font-size:10pt;">the motor is under load it will be drawing a lot more amps & develop a</div><div style="font-family:Arial, sans-serif;font-size:10pt;">lot more heat.</div><div style="font-family:Arial, sans-serif;font-size:10pt;">But people run the Minnkotas with air compensation & get away with it.</div><div style="font-family:Arial, sans-serif;font-size:10pt;">Alan</div><div style="font-family:Arial, sans-serif;font-size:10pt;"><br clear="none"></div><div style="font-family:Arial, sans-serif;font-size:10pt;"><br clear="none">On 25/03/2020, at 2:09 PM, Brian Cox via Personal_Submersibles <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote style="font-family:Arial, sans-serif;font-size:10pt;"><div><div style="font-family:Arial, sans-serif;font-size:10pt;"><font size="2"><font face="Arial, sans-serif"> Alan, </font></font><div><font size="2"><font face="Arial, sans-serif"> In my case my motor pod contains about 8 gallons of WD40 . I ran the motors the other day , all day long for about 10 hours straight . The temp outside was around 60 F so it sort of simulated our water temperature here. I was surprised to discover that the expansion of the oil was not as much as I thought it would be , it was about 1/2 gallon. It reached a point where it stopped expanding, so I guess it reached a point of equilibrium with respect to the temperature. One problem I have is in the summer the oil actually expands more than when the motor is running just sitting there heating up from the ambient temperature. I think in the summer I'm going to disconnect the hose and put it into a bucket when sitting. </font></font></div><div><font size="2"><font face="Arial, sans-serif"><br clear="none"></font></font></div><div><font size="2"><font face="Arial, sans-serif">Brian</font></font></div><div><font size="2"><font face="Arial, sans-serif"><br clear="none"></font></font></div><div><font size="2"><font face="Arial, sans-serif"> </font></font><br clear="none"><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">--- <a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a> wrote:</span><br clear="none"><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">From: Alan via Personal_Submersibles <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>></span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">To: Personal Submersibles General Discussion <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>></span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Subject: Re: [PSUBS-MAILIST] motor oil compensator</span><br clear="none"><span style="font-family:Arial, sans-serif;font-size:10pt;">Date: Wed, 25 Mar 2020 13:25:53 +1300</span><br clear="none"><br clear="none"><div style="font-family:Arial, sans-serif;font-size:10pt;"></div><div style="font-family:Arial, sans-serif;font-size:10pt;">Brian,</div><div style="font-family:Arial, sans-serif;font-size:10pt;">there is this military de-classified 1972 document on pressure compensating.</div><div style="font-family:Arial, sans-serif;font-size:10pt;"><a shape="rect" href="https://apps.dtic.mil/dtic/tr/fulltext/u2/894795.pdf" rel="nofollow" target="_blank">https://apps.dtic.mil/dtic/tr/fulltext/u2/894795.pdf</a></div><div style="font-family:Arial, sans-serif;font-size:10pt;">I printed it out & had it bound.</div><div style="font-family:Arial, sans-serif;font-size:10pt;">I found that the rotation of the motor was throwing the oil out of the motor</div><div style="font-family:Arial, sans-serif;font-size:10pt;">housing & up in to the compensating tube. If you dived there would be added</div><div style="font-family:Arial, sans-serif;font-size:10pt;">pressure to keep the oil in the motor housing, but this wouldn't happen transiting</div><div style="font-family:Arial, sans-serif;font-size:10pt;">on the surface. As the oil also keeps the Motor cool, there may be a danger of</div><div style="font-family:Arial, sans-serif;font-size:10pt;">the motor overheating in this instance.</div><div style="font-family:Arial, sans-serif;font-size:10pt;">As you will find in the linked manual, a minimum of 5psi over pressure is the norm.</div><div style="font-family:Arial, sans-serif;font-size:10pt;">I am going to use the same system as Cliff, with the relieving regulator dialled</div><div style="font-family:Arial, sans-serif;font-size:10pt;">up to 5psi to give an overpressure. However my system has oil in it so I get it's </div><div style="font-family:Arial, sans-serif;font-size:10pt;">cooling advantages & eliminate large air volume changes.</div><div style="font-family:Arial, sans-serif;font-size:10pt;">Alan</div><div style="font-family:Arial, sans-serif;font-size:10pt;"><br clear="none">On 25/03/2020, at 11:19 AM, Brian Cox via Personal_Submersibles <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote style="font-family:Arial, sans-serif;font-size:10pt;"><div><div style="font-family:Arial, sans-serif;font-size:10pt;"><font size="2">Seawater gets compressed up the hose, so never goes above the highest point of the hose. When oil heats up it spills into trap and cannot escape to the sea. </font><div><font size="2"><br clear="none"></font></div><div><font size="2">Brian</font></div><div><font size="2"><br clear="none"></font><br clear="none"><span style="font-size:10pt;">--- <a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a> wrote:</span><br clear="none"><br clear="none"><span style="font-size:10pt;">From: Øystein Skarholm via Personal_Submersibles <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>></span><br clear="none"><span style="font-size:10pt;">To: Personal Submersibles General Discussion <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>></span><br clear="none"><span style="font-size:10pt;">Subject: Re: [PSUBS-MAILIST] motor oil compensator</span><br clear="none"><span style="font-size:10pt;">Date: Tue, 24 Mar 2020 22:21:15 +0100</span><br clear="none"><br clear="none"><div dir="ltr" style="font-size:10pt;">You should avoid contact between the seawater and the oil. The oil will contaminate quickly and it will no longer be dielectric. <div>Just the hose from the motor to the tee is enough to compensate. You do not have to have a large volume of oil. Fill the hose with oil and cap it off, done. or make a neat yet more sophisticated solution. </div><div>Make the end lid of the motor as a flange assembly and instead of a lid, use a rubber diaphragm. This will then act as a compensator. You can even install a light spring pushing down on the diaphragm if you want a slight internal overpressure. </div><div><div><image.png><br clear="none"></div></div></div><br clear="none"><div style="font-size:10pt;"><div dir="ltr">tir. 24. mar. 2020 kl. 21:28 skrev Brian Cox via Personal_Submersibles <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>>:<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">Here is a drawing for my oil compensator</font><div><font size="2"><br clear="none"></font></div><div><font size="2"><br clear="none"></font></div></div>_______________________________________________<br clear="none">
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</blockquote></div><br clear="none"><div style="font-size:10pt;"><br clear="none"></div><span style="font-size:10pt;">-- </span><br clear="none"><div dir="ltr" style="font-size:10pt;"><div dir="ltr"><div>Vennlig hilsen<br clear="none">Øystein Skarholm</div><div>91369599</div></div></div><span style="font-size:10pt;">
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