??Fishfinder going cray??

[AzAngler]

I need some advise on what to do here. Have a Hummingbird 717, mounted it on an aluminum 16' V-Hull. Directions say to mount at least 15" away from the motor. Mounted the transducer 16" from the motor, level and on the transom. Took the boat out on a small river and seemed to work good, lots of stuff I don't understand showing up on the screen. So I decide to move it to the bottom of the boat and then took it to a deep canyon lake. After I start out all kinds of fish show up, I mean LOTS! Almost as if the unit was being over loaded with info, at times it was reading depths of 200-1000'. After a while I gave up trying to figure it out, If I stop and drift it seemed to work. Not real sure what is going on or if I have all the settings messed up but it was real frustrating. I would like to find a "Boating electronics for dummy's" site or a place that has info on how to set up this stuff. The main reason I bought this system is for the depth, structure, and fish. So far it has left me confused Anything will help

P.S. After all that, we did catch some awesome fish!

 

[fishmen111]

Re: ??Fishfinder going cray??

I am going to guess that you had it on "fish id" mode. Some of what you were actually seeing were air bubbles being reflected back as fish. Some were a thermoclature and a few were probably fish. Turn off fish id (if on) or reduce the sensitivity. Your transducer is probably not positioned correctly. Same for your depth variations. Transducer bottom should be level on the horizontal, 1/8-1/4" below transom tilted back about 5 degrees. If your boat is flat bottom or has rivets, it may very hard to get high speed readings period.

 

[jtexas]

Re: ??Fishfinder going cray??

when you said "move it to the bottom of the boat", what does that mean, exactly?

 

[AzAngler]

Re: ??Fishfinder going cray??

Cool, I will try some of this stuff. Here are some pics and I definitely think I have it mounted wrong now. Before I think I had it right, but now it is at least 2"-2 1/2" below the bottom. Let me know what ya think. In Pic 2 you can see some grey RTV that is covering the old holes from the first mount, just left of the plug

 

[fishmen111]

Re: ??Fishfinder going cray??

Can't check the photos Az as my firewall is blocking them but if you were that far below the transom, the transducer was way too low. Try to picture yourself looking at the back of the boat while cruising wide open. You want the bottom of the transducer to just "skate" on the surface of the water without digging in (usually indicated by a small rooster tail).

 

[Silvertip]

Re: ??Fishfinder going cray??

Look at the transducer from the side and imagine a horizontal line right through the middle of it. Now mount the transducer on the back of the boat at a height so the horizontal passes flush with the bottom of the boat. DO NOT mount it so it is in-line with any protrusions ont he bottom of the boat. You definitely have it wrong right now. Any debris that you run over will rip the transducer right off the boat.

 

[jtexas]

Re: ??Fishfinder going cray??

not to mention which, your transom needs to be supported by bunks.

 

[fishmen111]

Re: ??Fishfinder going cray??

Whoa Az...can't say as I've seen that before. You have the mounting bracket on the bottom of the boat. It needs to be mounted on the transom (vertical, near the plug in your photo) with just the bottom edge of the transducer below the bottom of the boat.

 

[AzAngler]

Re: ??Fishfinder going cray??

How does this look? Mounted it back close to where I had it before, or should it look like the Picture I made, middle of the transducer in line with the bottom of the boat? I did make sure I placed it in an open area of the hull free from rivets and ribs.

 

[ziemann]

Re: ??Fishfinder going cray??

I would bring it up as the drawing shows. My Humminbird 981c has 2 transducers with a toggle switch- one transducer for slow speed and one for high speed. Both of my transducers are almost flush with the bottom of the boat- maybe 1/4" to 1/2" below the bottom... I use one of those plastic transducer mounting blocks to keep the drilling into my transom to a minimum....

 

[jtexas]

Re: ??Fishfinder going cray??

way better - give it a try - mine's just a bit higher.

those holes you made in the bottom - whatever you filled 'em with - if it wasn't Marine-Tex, I highly recommend replacing it.

 

[Silvertip]

Re: ??Fishfinder going cray??

In the picture just above your drawing, there is a tube-like deal just to the left of the transducer. That may produce turbulence around the transducer which causes it to go nuts. The transducer really cannot be anywhere near any such protrusions. Height is ok.

 

[AzAngler]

Re: ??Fishfinder going cray??

What is "Marine-Tex" jtexas and where would I buy it? Keep in mind that this is an old aluminum craft that I acquired, if you look in the background of my pictures you can see a tow truck, that is what I do and also how I acquired this boat. Needless to say the boat is kind of a beat around boat, lots of dirt roads leading to small mountain lakes and reservoirs, so mostly I just spread some silicone on leaks as I find em. Would be cool if I could find some good stuff.
And what if I was to move the transducer over the drain plug? I have 2 plugs, one on either side so I'm sure I won't miss one. I am going back to the same lake as last time so I would like to have it work as it should. Going after some 24" Rainbows and if I could read the bottom, get a good depth reading I think I can increase my odds on hook-ups.

Thanks for all your input, this place is AWESOME!

 

[fishmen111]

Re: ??Fishfinder going cray??

Az, you can get Marine-Tex at any hardware or boat store. It is awesome stuff for sealing anything below the water line. I also highly recommend it. Don't get in too much of a hurry with your current transducer placement. Try it first and let us know how it works. Still may need some adjustment. Best of luck on the rainbows!!! Beautiful fish.

 

[Silvertip]

Re: ??Fishfinder going cray??

You cannot mount it OVER the drain plug as it will be too high and at slower speeds the turbulence around the plug will cause a problem. .

 

[AzAngler]

Re: ??Fishfinder going cray??

Actually I was going to eliminate the plug altogether and place the mount over the hole after being sealed, would be far enough away from the pipe on the left. Thoughts? Just how big of deal is it with turbulence? Can only hit about 15mph with a light load and one person, usually only doing about 1-3mph trolling. After looking at my pictures, I am a little concerned with that pipe. Really thinking of moving the transducer now.