Another FishFinder Question.....

While I was in the bathroom tonight, I got to thinking. This is where I do most of my thinking, but this time I was in the shower.:p... I was thinking that I finally have my boat ready for the Fall and Winter fishing season with only 1 small flaw. At speeds under 10 mph, my fishfinder will register the depth accurately...or close enough. But at speeds over 10 mph I get depth reading of 957 ft, or some crazy number. I was told that maybe the transducer was coming out of the water or that maybe it needs to be adjusted just a little. My transducer sits about 1/2" below the bottom of my boat so I figure that cant be it. So the last time I took it out I tried some adjusting and still got the same crazy readings. I can live with it but I dont like it...Then tonight it hit me...This fishfinder is on my console and wired up to my cranking battery. It is possible that I am getting interference from my outboard motor just like a trolling motor can cause interference to a fishfinder??..Maybe the lower speeds are nor creating enough "noise" to bother it but the higher speeds are???...What do yall think??

I don't think that is the the problem. I have a 997 and have the issues. I think it's because I can't get the transducer in the water deep enough to get out of the turbulent water. I have tried everything and nothing has resolved. Just have to live with it I guess. Buddy has his on a fiberglass and has no problems. However, he has the ideal location to mount transducer, in front of motor inside a cutout. Like it was designed for this purpose. I am open for any suggestions from anyone else.

Aside from the plate yours is mounted on, looks just like where mine is mounted. Maybe we'll find an answer!!

One thing I would suggest on the installation above is to move the transducer in the middle of the ribs. You may be getting some turbulence off of the rib.

Yep, that's my thought too. That rib is throwing off turbulence. At speed, the water is folding over onto the transducer. At a miniumum, center it between the ribs. Now, having said that, mine is centered on the ribs and I'm getting crazy readings at speed too, but if I don't hammer the throttle and build to speed, I can keep a reading up to about 20 to 25 mph. Turbulence off a tin boat is a given, so to some degree, it's always going to be a problem. Worse than turbulence, air flowing under the ducer will cause it to loose signal even quicker. If you've got a riveted hull, those rivets are probably the source of the problem. See if you can pick a line between the ribs and between the rivet seam. Might help some, but it's still not going to be perfect - chances are.

Wannabe...

2 items yes 1 is the rib , I had to trim 1" off my trailer bunk so I could get centered tween ribs. 2, Too bad TnT & jeep are not neighbors as they could share this bracket I have/use from my old Low. days of switching unit & ducer between 2 boats. This bracket allows me to get ducer lower than I could mount just using Plastic mount board.
Transducer Brackets for Outboard Motors
This bracket takes all the guess work- without drilling one hole-out of mounting a ducer. Because I found I had to mount ducer lower than I could on plastic board I just use the bracket all the time. Works for me.

I like the idea of that bracket. I know this would solve my problem. The only thing that scares/worries me is the lake I mainly fish in is loaded with stumps. But thats the chance I just may have to take to get it working right. Here are some pics of it. As you can see, it is mounted below the bottom of the boat, it is pretty much between the ribs, and there are rivets on the bottom side of the boat that I suspect is the source of the problem.

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TnT look at Ur last pict see rivets but also see another RIB about 3 or 4 feet at most, dead ahead of Ur Ducer, bet that's your bad guy. As U speed up & boats lifts up a little this rib is throwing at wake a your ducer. Sorry don't have a nicer answer.

Jaxsprat, How does that bracket work at high speeds? Or do you have to take it out? Saw that a month or so ago and wondered if it would work. Thanks all for the info on the rib Wannabe and Joby. My question is it better to be too close to the motor or off of the rib more?

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After looking at this picture for a while, I think I have 3 problems that can cause turbulence and erractic readings...#1-Rivets...#2-the rib or skag located directly in front of the transducer...#3- The top of the transducer is below the bottom of the boat that is probably extra turbulence.... I really dont want to go any deeper in the water so I think this is what I am going to do: First of all, I am going to move the transducer up to where the bottom of the transducer is even with the bottom of the boat. This will eliminate extra turbulence caused by the transducer itself. I dont think this will solve the problem, but it aint gonna hurt anything. The 2nd thing I am gonna do is nothing!!!...I guess I am just gonna have to live with it. I'll just have to mark some waypoints on my GPS while going at lower speeds and just follow those waypoints in the future when I am going from one spot to another. Maybe a little time consuming, but at least it will be a tool to know I am running in the depth of water I feel comfortable at....The other option will be to just follow yall around:p....Thx for all the input everyone!!