Transducers, Losing depth marking while moving

My dealer installed a Helix 8 Mega Si Di unit in my new boat. I have the unit set on the 'mega settings', but when I go over about 10 - 15 mph, I lose contact with the bottom and lose any depth readings.

Is there a khtz transducer setting that will allow me to keep contact with the bottom while moving just on plane?

Other HB units (Helix 7) I've had I could do this.


Thanks in advance,

I think you are getting turbulence interference.....if it is through the hull transducer you may not be able to do anything there. Mine is on a bar on the back of the boat. I had that same issue and I moved it. down a bit and it was much better. Hope that helps.

Arnie

I'm not an expert but transducer placement is key.Is it mounted on a board so you are able to move it up or down,you may have to adjust the position a couple of times to find the right spot. Because it looks level sitting on the trailer dosnt mean its sitting level in the water while up on plane.My dealer installed unit never worked well at all. Found a good youtube video that uses a torpedo level and a bunch of coins to determin level while in the water so you can use thatmethod while on the trailer and level the transducer while on land. hope this helps Dan

Yeah, just a slight adjustment could be the difference

I think you are getting turbulence interference.....if it is through the hull transducer you may not be able to do anything there. Mine is on a bar on the back of the boat. I had that same issue and I moved it. down a bit and it was much better. Hope that helps.

Arnie

I agree with Arnie about turbulence interference.

I have the same issue on my Helix 5, but it works fine at troll speed, so I just live with it rather than drill more holes in the transom.

SDC

I think you are getting turbulence interference.....if it is through the hull transducer you may not be able to do anything there. Mine is on a bar on the back of the boat. I had that same issue and I moved it. down a bit and it was much better. Hope that helps.

Arnie

I agree with Arnie about turbulence interference.

I have the same issue on my Helix 5, but it works fine at troll speed, so I just live with it rather than drill more holes in the transom.

SDC

had the same issues with humminbird as well it all went away when i switched to Garmin lol

The placement and angle are critical and require tweaking if necessary


Doesn't mattter what unit I have found

The moral of the story is make it adjustable and play with the up and down and or side to side till you get it right. When the boat goes to plain and it is in the turbulence of the boat or the motor it will blank out at higher speeds. Think about how it sends a signal off solid objects but that air in the water blocks or deflects the signal.

If anyone is going to use a shoot through the hull....try the location first by using a removable adhesive like silicone before you use a permanent seal like marine goo.

Arnie

My transducer is not a 'through the hull' type, it's on the transom.
Since I'm boating on Georgian Bay, I'll look into moving the transducer a bit lower to ensure it remains in the water at all times to get a depth reading.
I've had the boat only 3 weeks, and I don't need any more dents in the prop....lol.

Your intuition to move it down unfortunately is not correct.

Moving it down causes more turbulence and your losing sonar due to bubbles running under the skimmer head. When objects move fast through water they create cavitation and that’s your issue with having it to low.

Your transducer bottom needs to just skim the top of the water to keep it working.

When I first install the same transducer your using I installed half the skimmer below the level of the hull. I would owe contact at about 10 mph. I kept raising it until it was just barely skimming the water and now I can get about 30 mph before it cuts off.

All transducers work this way. It not the manufacturer but each skimmer needs to be tweaked based on its shape.

I have installed quite a few. Do what others said and mount a hard plastic plate to your transom. Then mount your transducer to that so you can move the mount again and again until you get it right.

Also do not mount it close to your motor. Mount it off to one side by a couple of feet.

I have a similar issue with losing depth readings but this only seems to happen when I am fishing 75 feet or more -- the unit (a Humminbird 385ci) works just fine in lesser depths. It's not a turbulence issue as this happens while ice fishing or out in my canoe. I have attempted to adjust settings but the problem remains. Thoughts?

That will work for you.....I also agree with Disco as mine is just skimming when on plane. I am on Bay too out of Waubaushene...lots of rock there and the water is lower than it was in the Fall so be careful.

Arnie

Arnie, the reason I'm so nervous about losing the depth readings is the current low water situation on Georgian Bay.
I just nicked the boat prop on a rock after launching it for the first time. I hadn't even tied up the boat at the dock yet.
Then I really nailed it on a rock at a location I've traveled over many times before.

It just so important to have depth reading and your 'shallow depth alarms' set on the graph.
I'm going to do the plastic plate idea and have the ability to move the transducer around a bit without drilling more holes in the boat each time. I have to get those depth readings or I'll be buying props by the dozen.

Thanks for the good advice guys!

Michael

Have you tried adjusting the angle on the transducer?

I have had that issue with some units in the past and it is a matter of getting the angle right.

I had the problem on a Eagle sonar and adjustments didn't work. Had to repalce the tranducer as it had gone faulty.

Ralph

I had my first humming bird installed by the dealer and I could never get over 22mph before losing bottom. I than put my garmin on my self following the instructions and guess what I had to put it on the other side as the spin of the proper was a certain spin and i put it the proper distance from the prop. Now I can go 35mph and still have bottom. So make sure it on the proper side and distance from the prop.