Installing a transom transducer

[acdc96]

I just bought a humminbird fish finder model 561DI for my aluminum boat. I need to install the transducer but don't know where on the transom to install it? I know how to mount it and all that but the last one I installed on the transom didn't work at high speed (idk if it should work at high speed on such a light boat) but the last one I had was ripped off somehow last year while trailering the boat. Last time I had it on the port side of the transom. The manual was no help at all. So where should I mount it ?

 

[airshot]

When mounting on an alum boat the bottom of the transducer needs to be approx. a 1/4-3/8" below the hull and NOT inline with a line of rivets nor put it in line with a rib in the bottom. The transducer has to have as much undisturbed water coming off the bottom as possible. The transducer needs to be angled slightly backwards so the water coming off the bottom hits the face of the transducer and is not deflected to the top or sides. Air bubbles getting onto the face is what causes them to not read. The newer rounded transducer are much easier than the older flat style. Use a straight edge coming off the bottom of the boat to set the height and angle of your transducer, sighting by eye is not good enough. I have had a number of alum boats over the years and a little experimenting with height and angle is sometimes needed to find that sweet spot. My Eagle unit reads well at 34 mph on my current alum boat.