798 SI tranducer Rooster tail

Went out today to try my unit. Everything went pretty good and I recorded most of pembroke creek. Found about ten new brushpiles that I did not know were there. I also found that the rooster tail from the transducer is no joke. Thing was spraying my motor cowling down pretty good. Checked air intake when I got back to marina and it was dry inside still but man the water gets close. Checked transducer height and it was down below the hull a bit. No wonder it was throwing so much water. I am going to lift the transducer up to where the little line on the side of the transducer lines up with the bottom of the hull. Do You guys think that this will take care of most of the rooster tail? hard for me to tell because the transducer is so big. Also getting a line just on the left side of center line of SI view. This also shows up on DI. Left side also shadows out much quicker. You would think I am getting a partial blocking of the transducer but it is seeing clear where it is right now. Don't know.CF

I got the same spray on my motor from the SI transducer. Here's a picture I have of the transom. You can see the shield I made to stop the spray. You might try raising the transducer first. I have a deep v hull and have the line on the side of the transducer even with the hull bottom on the low side. So the high side is running much deeper. I have good readings at all speeds, so rather than messing with the transducer height, I made the shield.

If your transducer is mounted on the right side of the motor and you are seeing a constant line on the left side than what you are probably seeing is the motor or something else to the left of the transducer is blocking part of the left Si sonar beam. Raising the transducer will probably make this worse. A quick way to tell if it is something physically blocking the left Si sonar is to take the boat out of gear and let it drift. If the line is still there than there is something in the way. If it goes away than it may just be the turbulent water flowing off the left side of the boat hull that is causing it. Lowering the transducer or relocating it will help both of these causes.

Thanks guys.CF

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Originally Posted by Shellback

I got the same spray on my motor from the SI transducer. Here's a picture I have of the transom. You can see the shield I made to stop the spray. You might try raising the transducer first. I have a deep v hull and have the line on the side of the transducer even with the hull bottom on the low side. So the high side is running much deeper. I have good readings at all speeds, so rather than messing with the transducer height, I made the shield.

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Is That aluminum sheeting You used for Your shield? How thick is it? Does it flex when running? Thanks for the idea. My problem is My ducer is not mounted on starboard. It is transom direct. I had to do it that way because the starboard would offset it too much and put it in direct line with the back lower corner of my jack plate. I am having to thread a needle here and am going to have a spray problem. Thanks for anymore help You can give Shellback.CF

CF,
I just realized that you have a 798 unit. :Doh:
Did you install the plug in the 798’s transducer when you installed it? This is a black squarish shaped piece of material that goes into the area formed between the transducer and the pivot arm of the mounting hardware. If not, go ahead and install it and see if that ends the roostertail.

Sent you a PM with the info you wanted, but here are a couple close up pictures.

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Originally Posted by Humminbird_Greg

CF,
I just realized that you have a 798 unit. :Doh:
Did you install the plug in the 798’s transducer when you installed it? This is a black squarish shaped piece of material that goes into the area formed between the transducer and the pivot arm of the mounting hardware. If not, go ahead and install it and see if that ends the roostertail.

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Thanks HBG. I don't think I did install that piece. I'll rummage through my stuff tomorrow and find it. I don't remember seeing it in the instructions. Did I miss it in there? My rooster tail is praying out from both sides of the transducer. Will that piece help with that? Thanks.CF

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Originally Posted by Shellback

Sent you a PM with the info you wanted, but here are a couple close up pictures.

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Thank You for the pics and info Shellback. That shield does not look like it extends much further back over the back of the ducer. It keeps the spray off pretty good? Thanks.CF

I used the rubber plug Greg is talking about, and it didn't help with the side spray. My shield works very well for the motor side, but I can still see spray to the outside. It's not a problem though. I would have extended the right side, but I didn't want to mess with the tie down. If you are making one, I'd extend the right side also. If I didn't have the strap problem, I think I would have made a 12" wide shield and centered it over the transducer, and bent each side down some.