SI transducer height

[wi_yooper]

It was suggested on the humminbird forum that I ask here as well. Hight speed is with a thru hull so no need for the transducer to be in the water while on plane.

I am mounting an SI transducer on a 2006 Ranger 519 using a transomeshield jackplate mount onto a Bob's 6" plate. I cannot seem to find any specifics on the mounting height for the transducer relative to the hull step. On the 6" plate I need to drill all the mounting holes so I don't have a reference to start from. Do I need to be below the level of the hull step or can I be slightly above it to give the transducer a little better protection? If above the hull step, how high is too high?

Thanks much,
Joe

[bobcoy]

Too bad! I thought the Ranger forum would help, but maybe just call Ranger direct. Bob

[jc2bg]

That is a question neither Ranger nor anyone on this forum can accurately answer, because there are too many variables. One indeterminate variable, unless one is looking at the boat while in the water, is how low the boat rides in the back. Not every boat is loaded the same or has the same geometry, especially when they are older. The second variable is more related to Humminbird and what angle they consider optimal for side imaging [which I do not know]. What I do know is that when my dealer rigs late-model or new Rangers with side imaging, he typically mounts the transducer attached to the step, which keeps it ~6-8 inches below the water line at rest or slow idle. I can’t imagine that positioning the transducer really high in the water column, like 2-3 inches under the surface, would be a good idea, simply because of the angles involved. And unnecessary anyway. But if Humminbird doesn’t have a preference for depth setting, who would? And if any setting consistently under the water is fine, then the question really becomes, what position is less likely to be obstructed, etc.

[BRNut]

Agree with John again.......

For me, clean water about 4-7MPH but above the hull. I mounted one down to about 1 inch above the pad, last boat is onto the bottom of the jackplate hole shot plate.

Readings are pretty clean at about 5 MPH, cavitation at the transducer is not your friend.

Once in a while I am asked about clean water while on plane? Not sure you will get any reasonable readings that fast, even if you have clean non cavitating water over the transducer. Good images mean slower motion.

Best,

BRNut

[wi_yooper]

Thanks guys. Right now where I have it mocked up it would be almost identical to having it on the hole shot plate.