<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>It should be relatively easy to add reverse, but </div><div>I presume they are either on or off, so you would need the addition of</div><div>a speed controller anyway. It would be interesting to pull one apart.</div><div>There might not be much in the way of a thrust bearing, as the pump impeller </div><div>wouldn't have an axial load on the shaft like a propeller.</div><div>What brand was it again?</div><div>Alan</div><div><br></div><div><br><br>Sent from my iPad</div><div><br>On 13/12/2015, at 2:35 am, hank pronk via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px"><div id="yui_3_16_0_1_1449926923942_2618"><span>Alan,</span></div><div id="yui_3_16_0_1_1449926923942_2618" dir="ltr"><span id="yui_3_16_0_1_1449926923942_2830">I am still in favour of pump motors except I do not know how to reverse them. As far as I can tell they are not </span>reversible. The efficiency in oil comes from the extremely smooth interior of the motor. If you could reverse them, they would be perfect, they are cheap at about 200 dollars for a small 120v and they would be pretty easily modified to take a prop. Oh ya, and they already have thrust bearings. The oil inside was real stinky, kinda like antifreeze.</div><div id="yui_3_16_0_1_1449926923942_2618" dir="ltr">Hank</div> <br><div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12px;"> <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 Saturday, December 12, 2015 3:24 AM, Alan James via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br></font></div> <br><br> <div class="y_msg_container"><div id="yiv4037016340"><div><div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"><div id="yiv4037016340yui_3_16_0_1_1449865396752_6619" dir="ltr">Hank, </div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6619" dir="ltr">what ever happened to your idea of using a submersible pump as a thruster?</div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6619" dir="ltr">Have just been doing a bit of reading on oil compensation of submersible pumps.</div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613">In this article....</div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr"><a rel="nofollow" target="_blank" href="http://www.pumped101.com/oilvsair.pdf" id="yiv4037016340yui_3_16_0_1_1449865396752_6621">http://www.pumped101.com/oilvsair.pdf</a><br></div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr">it states that with oil compensation there is only a loss of about 1&1/2% efficiency </div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr">over an air compensated motor.....</div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr"> "What
does reduce an oil filled motor’s efficiency is the energy loss due to oil
circulation within the stator housing. </div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr">As a rule of thumb, this circulation
requirement reduces efficiency by about 1.5% when compared to an air filled
motor. "<br></div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr"> Of interest was that they base this on the use of an oil "Shellflex 210" which has a viscosity of 20.3 cst at 40C.</div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr">I was recently trying to track down a silicone oil of 3cst thinking that I would need a really low viscosity to get reasonable efficiency.</div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr">A chemist I spoke to said at that low a viscosity it would be flammable.</div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr">Alan</div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr"><br></div><div id="yiv4037016340yui_3_16_0_1_1449865396752_6613" dir="ltr"><br></div></div></div></div><br>_______________________________________________<br>Personal_Submersibles mailing list<br><a ymailto="mailto:Personal_Submersibles@psubs.org" href="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></div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>Personal_Submersibles mailing list</span><br><span><a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a></span><br><span><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br></div></blockquote></body></html>