Transducer Not Reading at High Speed

Hi guys,

I would like my Humminbird 788 ci transducer set up to reads well at high speeds. It reads great at slow speeds.

Per the install instructions the transducer is more than 15″ from my prop. There does not seem to be anything that would be interfering or making extra wake when moving at high speeds. I started with the transducer parallel with the hull as stated in the install instructions. I have moved it so it sits above than the hull and below the hull with no change.

When moving at high speeds the transducer reads depths like 600 – 900 ft when traveling over 15 – 20 fow and I get a snow storm of red and green pixels on the display.

Any ideas, suggestions or tips are greatly appreciated.

Thanks,

get a Lowrance….

actually though, on my “other brand” graph, i was having issues reading at high speeds, so i tilted the transducer “down” one click. that way there is more of the transducer in contact with undisturbed water.

typically loss of readings at high speeds is caused by the transducer getting disturbed water to it. so you just need to adjust it down a click.

worked for me and others i know anyways…

We need some pics. Show us your current installation from 2 perspectives; try to get the pics at the level of the transducer:

From the side

From behind

A third pic showing the hull ahead of the transducer would be helpful too.

That you’re collecting information at low speeds means that all of your components are working fine. Now we just need to deliver undisturbed water to the transducer.

pic 1 is the side shot

pic 2 is the straight on shot

pic 3 shows where the transducer was before I moved it.

The previous spot was under 12 inche3s from the motor and did not read well either.

a couple shot that show the underside of the boat near the transducer.

in pic 2 the transducer is in the top center.

It looks a little too high and it also needs to be tipped down a click or two. It looks like it would be almost completely out of the water on plane and it needs to be level with the bottom of your boat.

If I tip it down one click then it is level with the hull. When I had it like this I got all the clutter.

Should it be below the hull?

Russ, in all honesty that thing is about 1″ too high.

If you draw an imaginary line splitting the ducer in half (top and bottom) that should be parallel with the bottom of your hull.

in other words…Place a strait edge along the hull extending beyond the transom to create the parallel line that would then split the ducer (top and bottom).

And probly one click down too from the pic.

When looking from under the boat back you should see the lower half of the ducer. It might also help to move it a tad closer to center too. Since you will be most likely drilling new holes. -Mark

Way too high in two respects. Get that thing 1) further into the water slipstream (bottom of the boat should about intersect the midline of the tansducer, if not even a touch lower) and 2) further toward the engine. It’s going to have some major disturbed water issues at its current location, way up and out…..

Yep, yep, and yep.

It need to move down towards the bottom of the transom, and it needs to get closer to the motor and away from that angle. When you re-mount it, keep it away from the lines of rivets that are running parallel to the long axis of the boat. You may also consider mounting it on a transducer mounting board (< $15) so that re-positioning it doesn’t require yet another set of screw holes in the transom.

Thanks for the tips guys. I’ll move it tomorrow. I’m heading out tomorrow after work so I’ll let you know the results.

Thanks for the help guys

Russ, my humminbird transducer is approx. 4-8 inches from the motor(SI ducer,wanted it midline as possible) and I get best readings there for high speed-closer than recommended. did not expect this location to work for high speed, but it does. My lowrance, which is further out (12-15 inches) has the same issues from time to time at high speed, esp. in waves. I agree with the guys info they gave you.

Guys, I lowered the transducer so it was below the transom and it read a lot better at high speeds. No I get a monster rooster tail. What is the solution to get rid of that and still keep the transducer low enough to read at high speeds?

The Red Green way, which works just fine, is a bunch of wraps of black electrical tape to cover the hole that water is shooting up through.

Quote:

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The Red Green way, which works just fine, is a bunch of wraps of black electrical tape to cover the hole that water is shooting up through.

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That’s the route I took last night. I found it kind of ironic the answer to a problem on a very expensive piece of technical equipment is simple electrical tape. If it works, so be it.