898 trouble reading depth at +30MPH

I recently upgraded from a 917C to a 898 SI. Unit has been working great, but last week I was able to run and gun a lot more than I had been. At speeds of +25 or +30MPH my unit reads 1′ of depth in 20 FOW and the bottom signal on split screen is almost non existent. also the side digital reading is the same When I slow down to < 20 MPH, the signal is back. GPS works great at higher speed which was issue on the old 917C when I could overdrive the map at higher speeds. Is this a transducer issue?

They SI transducers never seem to read very well at high speed since they are designed for slow speed and high detail. Mine loses itself at about 20mph

I put in the Y cable and glassed a puck in the back of my boat. No issues unless I’m catching air at 50mph

Can still read bottom when I am at 33mph with mine. Could it be the location of the transducer?

Most Bird’s don’t read when you get going to faster speeds. There is another transducer you can get that will eliminate that at high speeds.

The ONLY reason it is not working is due to cavitation.

Mine works fine at 30mph, but it takes some tweaking to find the sweet spot.

Picture of your install will help.

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The ONLY reason it is not working is due to cavitation.

Mine works fine at 30mph, but it takes some tweaking to find the sweet spot.

Picture of your install will help.

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I have a high speed transducer and S.I. transducer for my 798 S.I. works flawless

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The ONLY reason it is not working is due to cavitation.

Mine works fine at 30mph, but it takes some tweaking to find the sweet spot.

Picture of your install will help.

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OR

I have a high speed transducer and S.I. transducer for my 798 S.I. works flawless

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That works too.
Just need the $90 switch. Don’t even need to change your settings when you hit the switch as the 2d will work without selecting the other transducer.
I also run the quadbeam, but haven’t fine tuned that for high speed since i almost never use it…Thought it would add value, but not really.

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The ONLY reason it is not working is due to cavitation.

Mine works fine at 30mph, but it takes some tweaking to find the sweet spot.

Picture of your install will help.

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X2! Spot on, they do work!

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The ONLY reason it is not working is due to cavitation.

Mine works fine at 30mph, but it takes some tweaking to find the sweet spot.

Picture of your install will help.

---

OR

I have a high speed transducer and S.I. transducer for my 798 S.I. works flawless

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That works too.
Just need the $90 switch. Don’t even need to change your settings when you hit the switch as the 2d will work without selecting the other transducer.
I also run the quadbeam, but haven’t fine tuned that for high speed since i almost never use it…Thought it would add value, but not really.

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You don`t need the switch just use a Y cable.

OH

thanks to all. I talked with Humminbird Customer Service/Technical. They confirm the best way to read sonar at higher speeds is to add the Y cable and a high speed transducer. cost about $100 total. I asked why Humminbird did not include both the SI transducer and the higher speed transducer since most people would want to read bottom when running across a stretch of water and not just rely on a GPS Lakemaster map? They told me they know, but it’s not included out of the box. They should have at least made mention that they highly recommend to add the high speed transducer or somehow include it in the SI transducer. It’s a shortfall. but they do have a fix. I just did not want to learn the hard way and run a ground

Many setups work great at speed with the SI transducer. Takes some tweaking but can be done my 182 TS Crestliner will read bottom just fine at 49 GPS with the SI transducer. I think most go the Y cable route to protect that $200 transducer from getting struck and broken. With the 2D transducer the SI transducer can be mounted above the bottom of the boat out of harms way.