FF Temp Reading High

[buzz]

I have Humminbird 386ci with the XTH-9-20-P transducer mounted on an Ocean Kayak Torque in the transducer shaped scupper.

The fishfinder works well except the temperature readings are high. I was getting reports between 69 and 70 down at Mattawoman on Saturday.

Anybody know why this would be happening?

The scupper port has an egg shaped outline as does the transducer. But I found mounting the fat end of the transducer facing the skinny end of the scupper port made for a more flush fit. Could the problem be that I mounted the transducer backwards?

[Runnin]

I don't know. I would have expected a scupper trnaducer to be accurate. Mine also read hot, but I have an in hull mount, and I think the temperature goes off when the sun hits the boat.

I do think temps on river are hitting near 70 degree mark.

[Cowpokey]

Mine was reading 71 at Tridelphia yesterday. Don't know how much different the surface temps are between tidal and non-tidal.

[assists21]

I have Humminbird 386ci with the XTH-9-20-P transducer mounted on an Ocean Kayak Torque in the transducer shaped scupper.

The fishfinder works well except the temperature readings are high. I was getting reports between 69 and 70 down at Mattawoman on Saturday.

Anybody know why this would be happening?

The scupper port has an egg shaped outline as does the transducer. But I found mounting the fat end of the transducer facing the skinny end of the scupper port made for a more flush fit. Could the problem be that I mounted the transducer backwards?

Buzz

I have the same setup. Mine was reading 66-67 on the Severn this am. Seemed accurate to me. Mine transducer though is aligned with the shape of the scupper. Not sure about mounting it backwards.


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[buzz]

Thanks.
I suppose that thin top layer of the water could have been that warm. Maybe next time I will bring a small thermometer I can dunk in the water for comparison.

[J.A. Veil]

There is a lot of daily fluctuation in surface water temperature this time of year. Take a look at the CBIBS data buoy site at http://buoybay.noaa.gov/observations/data-snapshot. Choose a location from the right side of the screen, then choose water temperature. You can get instantaneous readings or see graphs of the temperature over a 1-day, 7-day, or 30-day cycle. I don't know how far below the surface the buoy's temperature sensor is located. As Buzz notes, the very top surface water layer that a scupper transducer contacts will have an even more extreme fluctuation.

It is believable that the surface layer water temp could have exceeded 70 deg on yesterday's sunny afternoon.

[Turtle135]

My Humminbird 346C DI has a "temperature offset feature" buried in the advanced menu. Mine was reading about 1.5 degrees low from actual so I went into that menu feature and made the correction. The setting remains even after you power down.

[buzz]

My Humminbird 346C DI has a "temperature offset feature" buried in the advanced menu. Mine was reading about 1.5 degrees low from actual so I went into that menu feature and made the correction. The setting remains even after you power down.

Thanks Dave.
Took a little digging, but I found it.

Now I just have to remember to bring the thermocouple thermometer this weekend so I can calibrate.