<html><head></head><body><p dir="ltr">This might be an ideal application for a small hydraulic motor, with a pressure relief valve set to return fluid to tank at a relatively low pressure. Left to run throughout the dive, it would take up any slack until encountering the buoyancy force from the buoy, at which point the motor would maintain torque on the spool and excess fluid would just dump over the relief valve. You could further conserve power by only enabling the system when changing depth.</p>
<p dir="ltr">Sean<br>
</p>
<br><br><div class="gmail_quote">On October 8, 2016 5:04:28 AM MDT, hank pronk via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<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_1475923733180_2749">Hi James,</div><div id="yui_3_16_0_1_1475923733180_2749">Been thinking about your automatic spool for towing a surface buoy, can't remember if you mentioned an air motor. A simple air motor with a constant air feed could work. The motor and spool would have to be at the surface on or under the buoy. I am not sure how tight an air motor is, but if the motor could hold back low air pressure, it could work. The motor would be direct drive to the spool, in fact the air motor could be the spindle for the spool. If a constant low air pressure is fed to the motor, the line could be pulled out against that pressure. The pressure it build up( acting as a pump) would vent out the regulator. The sub could pull the line down and when the
sub surfaces, the air motor would wind in the line. I doubt a vane motor would work unless the vanes are spring loaded. A diaphragm based motor would be ideal.</div><div id="yui_3_16_0_1_1475923733180_2749">Hank </div></div><p style="margin-top: 2.5em; margin-bottom: 1em; border-bottom: 1px solid #000"></p><pre class="k9mail"><hr /><br />Personal_Submersibles mailing list<br />Personal_Submersibles@psubs.org<br /><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br /></pre></blockquote></div></body></html>