# transom mount transducer problem



## seaarc (Mar 25, 2009)

I mounted a transducer on my 1448 jon boat transom and it's creating a rooster tail behind the boat and will not read at full speed. The boat runs about 22 mph. Has anyone else had this experience? Do I have it mounted too low or too high or is this just because of the flat bottom the boat has? Thanks guys

Dave


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## Captain Ahab (Mar 25, 2009)

How do you have it mounted? On a bracket or just stuck to the bottom of the boat. If you are mounting it flush on the bottom - you need to move it forward to a spot with less cavitation


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## seaarc (Mar 25, 2009)

It is mounted on a bracket. Maybe you can see it in this picture.


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## Captain Ahab (Mar 25, 2009)

I see it - I think this is one of those things you can live with. My 16' MirroCraft also has teh transducer on a bracket - and has the same problem when at top sepped. 

You can try moving the bracket around and it might help. Good luck and let us know what you do


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## seaarc (Mar 25, 2009)

I think I may have it mounted a little bit low. Maybe if I raise it to where it is above the bottom edge of the transom it will eliminate the rooster tail but not sure if it will read at speed????

Dave


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## Captain Ahab (Mar 25, 2009)

seaarc said:


> I think I may have it mounted a little bit low. Maybe if I raise it to where it is above the bottom edge of the transom it will eliminate the rooster tail but not sure if it will read at speed????
> 
> Dave




You then run the risk of it not reading at all. I suggest trying to move it towards the center of the keel


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## Quackrstackr (Mar 25, 2009)

Captain Ahab said:


> You then run the risk of it not reading at all. I suggest trying to move it towards the center of the keel



I agree with the Captain.

It should be mounted about half way between your lower unit and the side of the boat, between the strakes. It also needs to be slightly below the bottom of your boat but only about 1/2" to 1".

Othwerwise, disrupted water around your transducer is going to cause it to not read at speed.


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## darb79 (Mar 25, 2009)

I had the same problem, the best thing to do is to try diferent mounting locations if you are really concerned about it. But with different locations means more holes under the water line. I still dont read at top speed, but I dont have as big a rooster tail.


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## lswoody (Mar 27, 2009)

As stated, you want it mounted low,(actually below the bottom) and in between the strakes. Try tilting the back part of the transducer down a little bit. It does not have to sit perfectly straight with the bottom of the boat. Your problem is a common one with tin boats. Good fishin, Woody


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## redbug (Mar 28, 2009)

lswoody said:


> As stated, you want it mounted low,(actually below the bottom) and in between the strakes. Try tilting the back part of the transducer down a little bit. It does not have to sit perfectly straight with the bottom of the boat. Your problem is a common one with tin boats. Good fishin, Woody



If it isn't mounted level you will not get a true reading, the signal shoots out on the angle and you wont get a clear idea of the depth you are in

Wayne


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## Quackrstackr (Mar 28, 2009)

redbug said:


> If it isn't mounted level you will not get a true reading, the signal shoots out on the angle and you wont get a clear idea of the depth you are in
> 
> Wayne



That is relative to how deep the water is. So long as it is only a very slight angle, you won't notice much difference under 15 feet. There is no difference between setting the transducer at a slight angle and the resulting angle to the bottom caused by walking from the stern to the bow, riding over waves or differing attitude of the boat while on plane when relatively shallow.


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## seaarc (Mar 31, 2009)

Thanks for the help guys. I moved it closer to the motor and up just a little. This got rid of the rooster tail but it still wont read at top speed.


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## Hanr3 (Apr 5, 2009)

Mikne doesn't read at top speed either.

Glad to hear its not just me.


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## seaarc (Apr 5, 2009)

Hanr3 said:


> Mikne doesn't read at top speed either.
> 
> Glad to hear its not just me.



Do you think maybe it's just the nature of a flat bottom boat?


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## Quackrstackr (Apr 5, 2009)

Could be part of it. My buddy's War Eagle won't read at speed either. The hull may just force too much air/turbulence in the chines.

Mine reads at 50mph. :mrgreen:


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## YamahaC40Guy (Apr 10, 2009)

Your fish finder looks like mine and if so, here is what I heard from the "experts" at Bass Pro. (mine is a Hummingbird PiranaMax 215) Apparently, these low-end units simply are not built to give you a reading at speed in the first place. I found that odd, but guess I see how that's possible. Mine works well (but with a rooster tail too) from 0-12mph roughly, then static appears... Top speed, the screen is almost black and even the depth it indicates is impossibly deep for where I'm running it.


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## seaarc (Apr 10, 2009)

YamahaC40Guy said:


> Your fish finder looks like mine and if so, here is what I heard from the "experts" at Bass Pro. (mine is a Hummingbird PiranaMax 215) Apparently, these low-end units simply are not built to give you a reading at speed in the first place. I found that odd, but guess I see how that's possible. Mine works well (but with a rooster tail too) from 0-12mph roughly, then static appears... Top speed, the screen is almost black and even the depth it indicates is impossibly deep for where I'm running it.



Thanks for the info. It could be a low end unit issue I had not thought about that.

Dave


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