My friend Jimmy Williams spent the day at Grapevine lake today with his new side imaging sonar.

There was a lot of discussion on here recently about the rock crusher and whether it in fact exists. Lots of interesting theories but no real answers.

Well now we know.














Great job Jimmy.

I'm in the mineing buisness and the third pic looks like a scalper screen of some sort.. As the rest its hard to be for certain, but it appears to have tracks like a dozer.. But it may be part of a portable crusher.. Don't know but thats my 2 cents....

Thanks Ernest and Guy,one of these days I will figure out how to post picks and save yall the trouble,I ran across it by accident and was suprised how far away from the marker bouy it was,last time out I spent an hour looking for it and never found it,txlipper I am not sure what it is but it would be vintage 50's as the lake filled up unexpectedly in 1957(I've been told),what a nice day to be at the lake,I cant give a fishing report since I spent most of my time playing with the hummingbird,I did see a few shad pop once in awile and it looked like the birds were working futher to the west.

Those shadows are great. They really help to show the true shape of things.

Thanks for the pics.

Greg

How does a sonar see shadows?

Come on Joe, think, sonar can't see shadows. But it can create them.

I'm told and have read that the "shadow" is the sonar shadow, not a light shadow. Of course it's dark down there. The black is the absence of the sonar wave (because the signal was returned by the object being scanned)

Wow, those are too cool, might have to invest in one myself

Even though I don't own one of those new SI sonar's, I would like to understand how it works. It's to bad I live so far away from those club meetings where I could get to see Ernest's sonar short courses. I guess I will have to wait for the next CD.

Very cool thanks for the post.

In the 3rd pic whats the big white thing in the black part. Lake monster!??

Mike,
It's most likely a school of bait that the boat went directly over...or it might be the Grapevine Lady of the Lake.

Joe,
The shadows created by sonar are not actual shadows at all the way we see and understand shadows. The sonar signal hits an object, and creates the illusion of a shadow on the opposite side of the object because the sonar signal can't 'see' that area. Just like the sun...the sun's rays hit an object from one side and are blocked from 'shining' on the other...and creates a shadow. So what appears as shadows on a sonar signature is actually the absence of the sonar signal because it's been blocked by something. Simple, huh.....

Joe, you can drive as far as CC. Meet me sometime and check it out and fish a bit. You're always welcome.

As seems to be the situation with a lot of lakes, Grapevine filled up faster than it was supposed to due to heavy storms. The equipment could not be pulled out because of muddy conditions. Over the years, some attempts have been made to remove the crusher as it was deemed a hazzard. During one of the attemps, it was pulled over on it's side and that's the way it is now. I can't remember where I came across this information, either the Grapevine Corps Office or a news article.

There is an unconfirmed rumor that a row of large dump trucks also got stuck and are "parked" in the vicinity.

The Mayor of Grapevine said there was some equipement left behind because the lake filled up so fast. I heard him talking about it when he was speaking on the history of Grapevine.