Problems with Depth Reading

I am having problems with my depth reading. What should I check?

This article will help guide through many common causes of incorrect depth or no depth displayed on your Humminbird, and correct the issue. 

Checking for depth while your boat is parked in your driveway or yard, or testing the transducer in a swimming pool, bucket or barrel of water is not an accurate test for sonar.

All tests should be conducted in a lake, pond, river or sea. Testing your transducer while out of the water can damage the transducer, the unit or both.

Today, with all of the technology available to us, we have some very valuable tools for identifying depth and sonar related issues. The handiest of those tools is a camera or cell phone. The other tools, if you have one of our combo products, is the Humminbird unit itself, and an SD Memory card.

If you have a Humminbird combo product that has a card reader and you have a memory card, you have two options available:

  1. Snapshot View - With an optional purchase SD memory card installed, you can activate the Screen Snapshot feature from the Accessories Menu Tab.  Once you initiate that snapshot, you can then export the image from the SD card and email the image to Humminbird Customer Service.  They always say a picture speaks a thousand words and in this case, it certainly can help us more quickly identify issues.
  2. Recording View - Again with an optional purchase SD memory card, you can make sonar recordings from your unit.  Those images can be exported from the card and the necessary files can be emailed to us for examination.

If you do not have a Combo product with a card reader, a snapshot from your cell phone or digital camera can be emailed to us just as easily.  Just be sure to include a detailed description of the problem along with the images to help us assist you quicker.

Other troubleshooting tips include:

  • No Depth - Consult the Common Checks Guide and make sure that all categories are fully verified.  All testing related to the transducer and depth performance must be performed with the boat in the water.  Sonar does not read through air and testing your product while your boat is trailered WILL NOT give you correct information.
  • Maximum Depth - Check that you are not trying to read beyond your depth sounders maximum depth capabilities. This is shown in your Operations Manual.
  • Features and Menus - For those depth sounders with the following features and menus, try adjusting them as stated:
  • Depth Offset or Keel Offset - Some models of depth sounders have a Depth Offset or Keel Offset feature. Be sure this has not been set so that the depth readout would indicate a depth of zero feet deep or a negative depth readout due to the current depth of the water. Check your Operations Manual for this feature and its use.
  • Sonar - Some depth sounders also have a Sonar menu that allows for the sonar to be turned Off. Be sure that this is set to On.  This is typically in your Express Menu.
  • Sonar Mode - Some depth sounders have a Sonar Mode feature under the System Options menu. Be sure that it is set to "down" if you are using the dual beam or multiple beam transducers or set to "side" if you are using the wide side transducer. Check your Operations Manual for this feature and its use.
  • Max Depth - If your depth sounder has the Max Depth menu, be sure that it is set to Auto.
  • Transducer Feature - Some depth sounders also have a Transducer Feature in the Options menus. Be sure that this is set correctly for the transducer that you are using. Check your Operations Manual for this feature and its use.
  • Lower Range - If your depth sounder has the Lower Range menu, be sure that this is set on Auto.

Check the Operations Manual and transducer cable for the proper transducer. Normally, the transducer type is marked on the cable within the first 6 inches from the connector end. The correct transducers to be used with your depth sounder are listed in your Operations Manual.

Common Checks Guide

  • Check for proper transducer installation, according to the Operations Manual. If the depth sounder reads correctly at slow speeds but not at high speeds, the problem is usually with the installation. Make sure the transducer has not "kicked up". If it has, simply reset the transducer by snapping it back in its bracket.
  • Check for any damage to the transducer or cable.  If you find damage, you can try to mend the cable.  If mending the cable does not solve the problem, you will need to purchase a new transducer.  Physical damage of cables is not covered by our warranty.   
  • If the transducer was installed to "shoot through" the boat hull, the installation may have degraded allowing air bubbles to be trapped between the transducer and boat hull. It may be possible to check for this by adding enough water inside the boat hull to partially cover the transducer. The water will displace any trapped air and may allow the transducer to work properly. If this happens, the only long-term solution is to try and remount another transducer in your boat's hull.
  • If you have a side imaging unit and your side imaging sonar does not function properly, check that the transducer is positioned on your trolling motor or transom properly. Remember that this special transducer reads out the sides and out of the bottom of the transducer. Do not mount this transducer next to other transducers, speed/temp gauges or motor. Doing so will block the signal on that side of the transducer. This should also be remembered when the side imaging transducer is mounted on a trolling motor as depending on the direction that the trolling motor is pointed in, the transducer may be 'viewing' the boat's hull. All transducers must be pointing straight down and have an unobstructed 'view' of the bottom to be able to give an accurate depth reading.
  • Some models have a water type selection.  If you are in fresh water, try changing the setting to Salt Water or Salt Water Deep.  If you are in less than 15 feet of water, you will also want to increase the Surface Clutter setting.
  • Check for Marine growth or other obstructions that may be on the bottom of the transducer.  There are specific paints available for transducers and they need to be water based. If you search under "antifouling paint + transducer" on Google you should come up with sites that allow you to buy these items directly.  Clean the bottom of the transducer with soap or detergent and water or lightly sand with sanding paper. This will help "wet" the transducer. When putting a transducer in the water, it may form air bubbles across the face or "eye". This can be simply rubbed away with your hand. Older model transducers have to be allowed to wet before they will work properly.
  • If you are using a transducer switch, unplug the transducers and plug them, one at a time, directly to the depth sounder to check for a problem with the switch. If the depth sounder functions properly, return the switch for service.
  • Check the transducer connector, depth sounder connectors, fuse, fuse holder and battery terminal connections for corrosion. If corrosion is present, clean it off by using an abrasive (sandpaper, battery terminal cleaner, etc.) or with a mixture of baking soda and water. Corrosion may cause a weak signal or loss of voltage to the depth sounder.  

Important! All testing related to the transducer and depth performance must be performed with the boat in the water.  Sonar does not read through air and testing your product while your boat is trailered WILL NOT give you correct information.  

Erratic Depth or Incorrect (Bottom) Readings

Before trying the following suggestions, if possible, turn your unit on without using any options or selections to see if the problem may be in the way the depth sounder was set up to operate. Turn all features on Auto and/or set all options to "Restore Defaults" using the Setup Menu tab.  

If possible, check your unit on a friend's boat that has the same type of unit and model number. This will indicate whether the problem is with the unit or with the accessories, cables and/or installation. If the unit still has the same problem on your friend's boat, return it along with a letter explaining the problem in detail. If the unit works correctly on your friend's boat, proceed with the appropriate suggestions below:  

  • Remember that the depth sounder measures the depth of water that is below the transducer. The motion of your boat riding up and down on waves can be detected by the depth sounder. Ensure that any variations in depth readings that you are experiencing are not due to the water conditions.
  • If the digital depth is different than what the graphical bottom reading is showing  it could be caused by a few things.  If you are in an area of a ledge or drop off and are using a wide area coverage transducer, it could be because of the following:
    • Your digital depth comes from the narrow beam of your dual beam product.  The graphical bottom reading showing up on your fishfinder is coming from the wider angle beam of your dual beam product.  If you are at a drop off or ledge that wide angle of the transducer could be hitting the shallowest part of the drop off and because it has detected a bottom it is displaying this shallower area as your graphical bottom reading.  
    • Be sure you are not trying to run two (or more) depth sounders at the same time. Using two depth sounders that run on the same frequencies can cause one or both to show incorrect depth readings. Check your Operations Manual for operating frequencies.
  • If you are seeing a double bottom on your sonar view, this is usually caused by an extremely hard bottom. Lowering the sensitivity will reduce this, but may not make it go away completely.

After trying all of the above if you continue to have problems and your unit has a card reader, the best way we can assist you is if you provide us with a sonar recording on sonar snapshot.  You can send us these recordings to the below email address.    

If you are still having problems after trying the preceding suggestions, please contact our Help Center.

Incorrect High Speed readings over 10 mph

This is typically the result of improper installation.  Getting a good high speed reading is highly dependent upon the installation of the transducer.  You may not get it correct the first time and you may have to re-install the transducer.  Our instructions for installation are general in nature because there are too many boat hull types to be specific.   

If you have a side imaging transducer only, it is possible that you will need to install a secondary transducer for your digital depth reading.  We suggest that you view this article that discusses high speed readings.  

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