Author Topic: Why don't pvc crappie condos show up distinctly on my SI or DI?  (Read 459 times)

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Offline mako9man2

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I'm confused as to why crappie condos made from pvc materials don't show up distinctly on either my DI or SI.  I can see fuzzy blobs and can measure their height (8' in this case) but can't see their outlines the way trees/branches show up distinctly.  The ones I am looking for are 8' tall and made like those in this picture(if I can get it to post).  They are anchored to the bottom and have flotation in the 4" center shaft that allows them to float standing up.  PVC is pretty hard but maybe not as dense as wood?

ila_rendered


Offline rnvinc

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Re: Why don't pvc crappie condos show up distinctly on my SI or DI?
« Reply #1 on: July 21, 2017, 07:57:35 PM »
Sonar distinguishes targets that are a different density than water  ...

Just so happens that PVC has a very similar density as water  ...

Rickie

« Last Edit: July 22, 2017, 07:10:28 PM by rnvinc »

Offline mako9man2

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Re: Why don't pvc crappie condos show up distinctly on my SI or DI?
« Reply #2 on: July 22, 2017, 12:04:04 AM »
Thanks Rickie.  I suspected it was something like that.

Offline TnTaz

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Re: Why don't pvc crappie condos show up distinctly on my SI or DI?
« Reply #3 on: July 22, 2017, 07:59:12 AM »
What type of screws are you using to attach the bucket pieces to the 4 in PVC pipe? What are you filling the center of the 4 in PVC with? I just found a good use for a bunch of old buckets.

Are you saying that the display shows only blobs on your screen? And no definition?

Offline mako9man2

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Re: Why don't pvc crappie condos show up distinctly on my SI or DI?
« Reply #4 on: July 22, 2017, 08:10:29 PM »
What type of screws are you using to attach the bucket pieces to the 4 in PVC pipe? What are you filling the center of the 4 in PVC with? I just found a good use for a bunch of old buckets.

Are you saying that the display shows only blobs on your screen? And no definition?

The gentleman who makes these just uses drywall screws.  If I were doing it I'd probably opt for stainless steel fence screws.  Buoyancy is some Styrofoam crammed into the top of the tube but pool noodles would work very well.  Either way you need to close the top to hold the flotation inside.

When I see one of these on my Helix screen it looks like a fuzzy cedar.  Very indistinct except for the height which is usually around 8'.  A typical tree with limbs shows up exactly like a tree.  You would think these would show up clearly but as Rickie pointed out PVC has nearly the same density as water hence the cloaking factor.  Probably not a bad thing if you want to keep this a secret.   

Offline rnvinc

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Re: Why don't pvc crappie condos show up distinctly on my SI or DI?
« Reply #5 on: July 23, 2017, 07:11:14 AM »
I have seen images of PVC structure where the PVC was capped and trapped air inside  ...

Air does indeed have a different density than water and shows up fairly well on Sonar  ...

Rickie

Offline TnTaz

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Re: Why don't pvc crappie condos show up distinctly on my SI or DI?
« Reply #6 on: July 24, 2017, 04:53:52 PM »
Thanks for the tip on the construction. With this heat we are having I think I have found a Saturday project.


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