Sonar at cruising speed

[coolings]

Greetings. I have a Garmin GPS with a transducer. The tranducer is mounted on the transom. When I am at cruising speed, the depth on the GPS goes haywire. I noticed the factory depthfinder on my boat can keep up. Is this expected. Or should the Garmin be able to keep up with an accurate depth? The transducer was professionally installed. It is not to close to the prop. It is below the water line while on plane. The only problem with the install may be that is it slightly to low. The manual states the transducer should be 1/8" below the hull, mine is maybe 1/2". I can post pictures later if needed.

 

[tdappleman]

You should be able to expect accurate readings at cruising speed. Where do you have the transducer mounted - it may be picking up disturbance near the prop or the hull itself. I have my transducer mounted between my inboards and it reads the same as the original depth sounder at all speeds.

 

[coolings]

That is good to know. I would like to have both working as a reference. I will post pictures of my mount location later. The boat is at MM having some warranty work done. Start key turn valve is causing problems.

 

[Hampton]

The mounting is critical. The unit itself can cause turbulence/cavitation with bubbles that will break the bottom lock. This could be due to being canted fore or aft, or I believe due to being mounted too deep or shallow. Can you recess it to 1/8" the way it is mounted? If you had it done prof'ly, and it is not within tolerance, and it doesn't work, make them get it right.