Transducer/Interference

[TNBronzeback]

So as i posted a few minutes ago, i just got my motor back and took it for a spin yesterday around the launch at HWY 109 in lebanon. at idle speed and about half throttle the sonar was great, crystal clear/no problems, but once i got some speed up, it got choppy and not the constant picture. Im sure some of you guys might have had this problem before as well. I have attached a few pics of where its mounted. (i used the same holes as the previous owner in an attempt to not put more holes in the boat, yet knowing once i get a gas motor i may need to) In regards to installation, its per Humminbirds instructions as far as how its lined up with the hull of the boat in an "up and down" situation, but im not sure if its now too close to the motor, or maybe the ribs at the bottom are throwing it off or what (Its more or less between 2 ribs now so im not sure). Anybody have any advice as to what i can do to make the unit clear again at full speed?
Also, i plan on getting one of those poly-type transducer mounting plates for when i need to move the transducer so i dont keep putting more future holes in the boat, after thats installed that is. Anybody have any recommendations on these?
Thanks.

[agelesssone]

Did you launch at Hunter's Point off of 231?

Does anyone know if that ramp is open yet since they rebuilt the ramp?

[SAMBOLIE]

I think you are getting turbulence from the either the prop or boat. I have had the same problem before. Fine at idle or low speed. At moderate speed or above it would show the depth where it was when it locked up regardless of water depth. When I backed off it returned to normal. Adjusting the sensor would work a while then it would revert back after a while.
I should have taken it to a knowledgeable repairman but never bothered as I only used it for recon or when using the TM.

[Buccaneer]

The ducer appears to be sufficiently "in the water" and as you have noted the readings are good at idle and low speeds. You are not getting "interference" from the motor. It looks to me like there is a line of rivet heads directly forward of the Ducer. In my opinion those rivets are giving off turbulence and/or cavitation bubbles that are causing the transducer to lose signal with the return ping. At low speed its not a problem.

[TNBronzeback]

Did you launch at Hunter's Point off of 231?

Does anyone know if that ramp is open yet since they rebuilt the ramp?

I launched at Laguardo Recreation Area. First time launching there, nice ramp.

i marked a TON of bait fish and some larger arcs in the area as well in about 20 ft of water, just wave after wave of bait, i would get little taps now and again, but nothing hooked, it really wasnt a fishing trip, just a motor checking trip, but i told my fiance, that the boat doesnt touch water without some form of fishing occuring even for just a cast or 2!

[TNBronzeback]

Yeah i know they can be kinda finicky, i will take a closer look under the boat in regards to rivets and see if i can move the ducer a little to either side to eliminate that. It's no good to me if i have to idle around the lake to get a good reading! LOL.
Thanks for the info guys!

[goreds.king]

The transducer mounting plate is a good idea. I put one on my 14ft jon boat. The owner before me drilled holes for a hummingbird transducer and I had a Lowrance. Instead of drilling more holes I used his existing holes to mount some plastic cutting board (purchased from Walmart). This allowed me to drill as many holes as I wanted without drilling into the boat.

[TNBronzeback]

The transducer mounting plate is a good idea. I put one on my 14ft jon boat. The owner before me drilled holes for a hummingbird transducer and I had a Lowrance. Instead of drilling more holes I used his existing holes to mount some plastic cutting board (purchased from Walmart). This allowed me to drill as many holes as I wanted without drilling into the boat.

Yeah i was hoping i could get lucky and be able to use the holes already there, but that wasnt the case.
I will certainly get me a transducer mounting plate before moving it.
Thanks!
Looks like the same boat i have, love the live well in to for extra storage!

[Transplanted Sportsman]

I agree with Bucaneer, it may be cavitation from the rivets or it may be the chart speed on your unit if you have a HB, I know for me I have a HB and all I used since spring was the trolling motor but the last two outings I took my small outboard and as soon as I would get above 6 mph my unit would no longer read, I got to look at the manual and it talked about the chart speed, i raised the chart speed on the unit and it took care of the problem, try it out before you remount it

[TNBronzeback]

I agree with Bucaneer, it may be cavitation from the rivets or it may be the chart speed on your unit if you have a HB, I know for me I have a HB and all I used since spring was the trolling motor but the last two outings I took my small outboard and as soon as I would get above 6 mph my unit would no longer read, I got to look at the manual and it talked about the chart speed, i raised the chart speed on the unit and it took care of the problem, try it out before you remount it

I thought about that as well but wasnt sure how chart speed on the unit was/would be affected by the speed of the boat. I will look into that though for sure, im taking it back out thursday morning and will try it then. a little piece me dies anytime ive gotta drill a new hole below the water line!

[Buccaneer]

http://www.bbcboards.net/humminbird-image-interpretation/172354-boat-speed-chart-speed-effects-side-imaging-down-imaging-2d-sonar.html

This guy is a wealth of info on the Humminbird units. You can Google his name and get loads of Youtube videos.

[TNtransplant08]

I don't mean to hijack this thread. But since you're on a similar subject, I thought I'd post on here, rather than start a new thread.

I'm leaning towards getting the Lowrance Elite 5 HDI this holiday and I'm exploring how I'll mount it onto boat. I know many people mount their transducer on their bow mount trolling motor when they have a sonar up front. Could I do that with a transom mount trolling motor or will there be too much disturbance with the signal?

[TNBronzeback]

I don't mean to hijack this thread. But since you're on a similar subject, I thought I'd post on here, rather than start a new thread.

I'm leaning towards getting the Lowrance Elite 5 HDI this holiday and I'm exploring how I'll mount it onto boat. I know many people mount their transducer on their bow mount trolling motor when they have a sonar up front. Could I do that with a transom mount trolling motor or will there be too much disturbance with the signal?

I dont see what the difference would be really. its still going to be mounted in front of the prop. its the same motor head whether its a bow mount or transom mount motor and the transducer gets mounted in the same spot regarding of the motor style. i would say you will be fine. that unit is down imaging unit so you wont have to worry about any side interference with the lower unit of the gas motor. i dont think you would have any problems out of it.

[TNtransplant08]

That's what I was thinking, but I wanted to make sure. I am leaning going towards that route, without having to drill holes in the boat. Thanks for the reply.