<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div dir="ltr" id="yui_3_16_0_1_1418622893245_4948"><span>Hank,</span></div><div dir="ltr" id="yui_3_16_0_1_1418622893245_4947"><span id="yui_3_16_0_1_1418622893245_4946">what about rotating thrusters that can go through 270 degrees?</span></div><div dir="ltr" id="yui_3_16_0_1_1418622893245_3609"><span id="yui_3_16_0_1_1418622893245_3610">You could put a motor drive on them & run them off joy sticks from anywhere in the sub.</span></div><div dir="ltr" id="yui_3_16_0_1_1418622893245_3607"><span id="yui_3_16_0_1_1418622893245_3608">It might be faster & less stressful on the electronics to have the motor just spin around.</span></div><div dir="ltr" id="yui_3_16_0_1_1418622893245_3607"><span>Alan</span></div><br> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;" id="yui_3_16_0_1_1418622893245_2709"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;" id="yui_3_16_0_1_1418622893245_2708"> <div dir="ltr" id="yui_3_16_0_1_1418622893245_2710"> <hr size="1" id="yui_3_16_0_1_1418622893245_3613"> <font size="2" face="Arial" id="yui_3_16_0_1_1418622893245_3606"> <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><span style="font-weight: bold;">Sent:</span></b> Monday, December 15, 2014 3:04 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] props<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_1_1418622893245_2707"><br><br clear="none">Alan,<br clear="none">This is for maneuvering thrusters on Gamma<br clear="none">Hank --------------------------------------------<br clear="none">On Sun, 12/14/14, Alan James via Personal_Submersibles <<a shape="rect" ymailto="mailto:personal_submersibles@psubs.org" href="mailto:personal_submersibles@psubs.org" id="yui_3_16_0_1_1418622893245_2712">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"> Subject: Re: [PSUBS-MAILIST] props<br clear="none"> To: "Personal Submersibles General Discussion" <<a shape="rect" ymailto="mailto:personal_submersibles@psubs.org" href="mailto:personal_submersibles@psubs.org" id="yui_3_16_0_1_1418622893245_3605">personal_submersibles@psubs.org</a>><br clear="none"> Received: Sunday, December 14, 2014, 8:34 PM<br clear="none"> <br clear="none"> I<br clear="none"> thought Gamma had an internal motor.Or<br clear="none"> is this for something else?You could<br clear="none"> run a propeller fore & aft of the motor, &<br clear="none"> the brushless<br clear="none"> motors I'm looking at have provision for<br clear="none"> that.But you<br clear="none"> would need two shaft seals & have that additional<br clear="none"> friction.It would<br clear="none"> make it more complicated bolting the motor can<br clear="none"> together.If you had<br clear="none"> the propeller that was back the front, trailing, then the<br clear="none"> flowcreated by<br clear="none"> the forward propeller might help compensate for the<br clear="none"> inefficienciesof the<br clear="none"> propeller for reversing.A lot of<br clear="none"> the thruster manufacturers ( of which there aren't many<br clear="none"> ) publicizethe<br clear="none"> forward & reverse thrust. That might be interesting<br clear="none"> reading.Alan<br clear="none"> <br clear="none"> From: hank pronk via<br clear="none"> Personal_Submersibles<br clear="none"> <<a shape="rect" ymailto="mailto:personal_submersibles@psubs.org" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none"> To: Personal<br clear="none"> Submersibles General Discussion<br clear="none"> <<a shape="rect" ymailto="mailto:personal_submersibles@psubs.org" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> <br clear="none"> <br clear="none"> Sent: Monday,<br clear="none"> December 15, 2014 2:09 PM<br clear="none"> Subject: Re:<br clear="none"> [PSUBS-MAILIST] props<br clear="none"> <br clear="none"> <br clear="none"> Alan,<br clear="none"> Another<br clear="none"> idea, make a thruster with a prop at each end of the motor,<br clear="none"> what do you think?<br clear="none"> Hank--------------------------------------------<br clear="none"> On Sun, 12/14/14, hank pronk via<br clear="none"> Personal_Submersibles <<a shape="rect" ymailto="mailto:personal_submersibles@psubs.org" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none"> wrote:<br clear="none"> <br clear="none"> Subject: Re:<br clear="none"> [PSUBS-MAILIST] props<br clear="none"> To: "Personal<br clear="none"> Submersibles General Discussion" <<a shape="rect" ymailto="mailto:personal_submersibles@psubs.org" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none"> Received: Sunday, December 14, 2014, 8:04<br clear="none"> PM<br clear="none"> <br clear="none"> <br clear="none"> <br clear="none"> Alan,<br clear="none"> Maybe it is better to make a prop<br clear="none"> that works in<br clear="none"> both directions. I can<br clear="none"> afford to loose efficiency, that is<br clear="none"> better<br clear="none"> than mounting two thrusters in my case.<br clear="none"> <br clear="none"> Hank--------------------------------------------<br clear="none"> On Sun, 12/14/14, Alan James via<br clear="none"> Personal_Submersibles <<a shape="rect" ymailto="mailto:personal_submersibles@psubs.org" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none"> wrote:<br clear="none"> <br clear="none"> <br clear="none"> Subject: Re:<br clear="none"> [PSUBS-MAILIST] props<br clear="none"> To: "Personal<br clear="none"> <br clear="none"> Submersibles General Discussion" <<a shape="rect" ymailto="mailto:personal_submersibles@psubs.org" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none"> Received: Sunday, December 14, 2014, 7:04<br clear="none"> PM<br clear="none"> <br clear="none"> <br clear="none"> Hi<br clear="none"> <br clear="none"> Hank,I guess<br clear="none"> you would be getting the same<br clear="none"> thrust in both directions,<br clear="none"> <br clear="none"> butyou would<br clear="none"> be doubling the pitch of the<br clear="none"> propeller by<br clear="none"> doubling up, &<br clear="none"> there maybe a lot<br clear="none"> of<br clear="none"> turbulance between the propellers.There<br clear="none"> <br clear="none"> are<br clear="none"> propeller calculators that take a<br clear="none"> number of input variables<br clear="none"> <br clear="none"> like hp, revs,<br clear="none"> boat size,intended<br clear="none"> speed, diameter of the<br clear="none"> <br clear="none"> propeller & pitch. You leave one<br clear="none"> <br clear="none"> input<br clear="none"> out & it calculatesthat for<br clear="none"> you. You<br clear="none"> could call the two<br clear="none"> propellers one (add the two<br clear="none"> pitches<br clear="none"> together) & see what diameter<br clear="none"> it<br clear="none"> calculates for you at a given pitch &<br clear="none"> <br clear="none"> play around<br clear="none"> till you get the most<br clear="none"> efficientdiameter /<br clear="none"> pitch<br clear="none"> combination; then<br clear="none"> use the diameter but<br clear="none"> halve the<br clear="none"> pitch.I<br clear="none"> <br clear="none"> don't think I made a lot of sense, but if<br clear="none"> you go down<br clear="none"> that path I<br clear="none"> will explain a bit<br clear="none"> better.However<br clear="none"> given that submarines<br clear="none"> <br clear="none"> operate better with bigger diameter,<br clear="none"> <br clear="none"> lower<br clear="none"> pitch propellersit<br clear="none"> <br clear="none"> probably isn't a<br clear="none"> good idea going to two<br clear="none"> smaller higher<br clear="none"> <br clear="none"> pitched<br clear="none"> propellers.Alan<br clear="none"> <br clear="none"> <br clear="none"> From: hank pronk via<br clear="none"> <br clear="none"> Personal_Submersibles<br clear="none"> <br clear="none"> <<a shape="rect" ymailto="mailto:personal_submersibles@psubs.org" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none"> <br clear="none"> To:<br clear="none"> <br clear="none"> <a shape="rect" ymailto="mailto:personal_submersibles@psubs.org" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a><br clear="none"> <br clear="none"> Sent: Monday, December<br clear="none"> <br clear="none"> 15, 2014 10:38 AM<br clear="none"> Subject:<br clear="none"> [PSUBS-MAILIST]<br clear="none"> props<br clear="none"> <br clear="none"> <br clear="none"> Hi All,<br clear="none"> If I build a<br clear="none"> thruster<br clear="none"> with an extra long<br clear="none"> shaft, then put<br clear="none"> two props on back to<br clear="none"> back, one prop<br clear="none"> reversed. <br clear="none"> Will the thruster perform equally<br clear="none"> in both<br clear="none"> directions?<br clear="none"> Hank<br clear="none"> <br clear="none"> <br clear="none"> _______________________________________________<br clear="none"> Personal_Submersibles mailing list<br clear="none"> <a shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"> <a shape="rect" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"> <br clear="none"> <br clear="none"> <br clear="none"> <br clear="none"> -----Inline<br clear="none"> Attachment Follows-----<br clear="none"> <br clear="none"> <br clear="none"> <br clear="none"> <br clear="none"> <br 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