Humminbird FF Question... weird

[Strike King]

I recently moved my transducer from my TM to the back of the boat bcuz im getting a 2nd unit for up front. so i was reminded of a interesting thing when i originally had the transducer on the back.

at slow speeds and idle the screen shows 0 to a normal about of fish

when i go full throttle the screen immediately fills with fish icons.

also when im floating or using my TM the fish icons seem accurate.

the unit i have is a Humminbird 777c and my motor is a Johnson 9.9

[Strike King]

pic 2

[acar555]

It looks to me that you are getting interference from somewhere.  What battery is the sonar hooked up to?  Or the transducer is mounted to high and you are getting air underneath it when moving.  This causes the screen to clutter up like that, and combinded with FishID turned on the unit "thinks" the clutter is fish, but really isn't.  Make sure the transducer slightly lower than the bottom of the hull.

[Strike King]

I have 3 batts and they are hooked up in parallel and my transducer is mounted as low as it will go

[Wayne P.]

Can you post a picture of the transducer mounting? You say it is mounted as low as it will go, but that depends on how/where it is mounted whether it is done correctly for your application.

[Hot Rod]

Looks to me like you aren't getting "smooth" free flowing water on the transucer when up to speed.  If its mounted to close to the motor or a hull strake you'll get false readings from the turbulence/bubles those cause as they pass through the water.

If it is already mounted so the transducer is riding below the hull, then you probably just need to adjust it more port or starboard on the hull to move it away from turbulence.

[Strike King]

i bet thats what it is....bubbles... i'll look to see if theres a better spot for the transducer.

[BobP]

Definitely bubbles from your prop and transom edge ventilating as it gets up on plane.  You want the Xducer away from the prop, 12-18" if you can get it.  However, if you're happy with FF performance when on plane and at low speeds while scoping out areas, I wouldn't worry about it.  After all, what do you need the FF for when getting up on plane?  Now, we gotta get your sonar set up to best detect fish and structure.  Step one - get rid of the fish symbols    Turn down/off the noise filter, set sensitivity to 75-90% max and learn how to interpret the detailed data shown in raw form on your screen.  

[Strike King]

Definitely bubbles from your prop and transom edge ventilating as it gets up on plane. You want the Xducer away from the prop, 12-18" if you can get it. However, if you're happy with FF performance when on plane and at low speeds while scoping out areas, I wouldn't worry about it. After all, what do you need the FF for when getting up on plane? Now, we gotta get your sonar set up to best detect fish and structure. Step one - get rid of the fish symbols Turn down/off the noise filter, set sensitivity to 75-90% max and learn how to interpret the detailed data shown in raw form on your screen.

alright cool i'll try that thanks!