<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div><span></span></div><div><div></div><div>Hi Brian,</div><div>the fish finders work like a car head light, so it would be hard to locate a </div><div>submarine that was outside it's cone of detection even if you moved it</div><div>around. If for instance you were 500 yards away & 100ft deep it would </div><div>probably be out of range & impossible to differentiate from anything else.</div><div>Alan</div><div><br>On 18/05/2019, at 3:34 PM, Brian Cox 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="font-family:Arial, sans-serif; font-size:10pt;"><font face="Arial, sans-serif" style=""><font size="4"> I've been thinking about some sort of pinger locator for my sub. I may get a commercially available one just as an extra safety measure, but in the mean time I was playing around with my depth finder on my sailboat . I was thinking if I had a rotating disk that would be a little higher than the sub the changing surface exposure to the sonar waves would appear on the depth finder as a recurring blip . I tried it with a radar reflector that I have, I tied it to a line and located it just below my transducer, I was able to move it around and observe the display on the screen. Since the radar reflector ( used on boats so big ships can see you) has all these sides to it, as I moved it around it would show up intermittently since the sound wave sometimes would not bounce back. I think a flat surface rotated so only the edge is showing and then a large surface was showing at a regular intervals could work as an indicator. I might be especially valuable if you were blending into the bottom so much as to not be detectable . That way someone with just an ordinary depth finder could detect you. </font></font><div><font face="Arial, sans-serif" style=""><font size="4"><br></font></font></div><div><font face="Arial, sans-serif" style=""><font size="4">Brian </font><font size="2"> </font></font></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></div></body></html>