Transducer Adjustment Question

[No Bail]

My depth finder has a difficult time reading at higher speeds. I lose the reading at about 30 mph. This is not a big deal as I only travel that fast in channels or where I know the water. If I'm catching too much air, my thought was to adjust the transducer up or down 1/16th inch.

It is mounted on the right side, just inside of trim tabs.

Any idea which way to go, slightly up or down to catch more clean water? Other ideas?

[Draggin' Bait]

Sounds like bubbles passing under the transducer. I'd first try tipping the aft end slightly down. On most models I've seen you can do that without drilling new screw holes. If there is anything in front of the transducer (e.g. rivet heads on an aluminum boat) then you may have to move the transducer entirely or just put up with it.

[No Bail]

Thanks for the info. I'll have to take a look and perhaps move it an inch or so.

[No Bail]

I finally got around to snapping a couple of photos of the transducer placement. What do you think? I don't have alot of room to move it. Suggestions?

[fish_on]

I wonder if the trim tabs are causing cavitation in that area.

[NorthRiverRick]

It's a tight sqeeze...

The problem is mostlikely air bubbles at speed. As mentioned previously try a slight tilt forward and drop it down a little deeper below the transom.

You may never get a great reading at full speed under all conditions but you might do a little better.

Good Luck

Rick

[FastActionRodTip]

only one way to find out at this point and since it's already done just run it around and see...no sense in moving it before testing again

[StickFish]

Looking at you chine and stern - is the outside edge of the chine (edge on the side of the transducer), it looks from the pic that it isn't welded the entire length of the chine - it looks like 6" - 8" there is a slot with no weld. If that is true wouldn't the new leading edge of the weld cause a little turbulance? What about further up the hull any slag that could be causing problems. No expert (reserving the right to be dumb as a post) but as speed increases the area of turbulance will lengthen in size.

[Catching Nemo]

I don't think the tab is the problem. Mine is mounted very close to a trim tab without any interference up to 39 MPH. I only start to lose bottom lock in hard turns.

The problem is forward of the ducer and maybe the strake is causing the problem. Regardles, you will need to lower the puck to catch cleaner water. I would lower the ducer, as far as you can, and see how it performs. If it doesn't lose lock, then start raising it until just before you have the performance issue. The left to right angle, on the ducer, should be straight up and down, not tilted, and parallel with an imaginary flat river bottom. From the photo is looks like it is off 5-10 degrees.

If it still loses lock, in the extreme down position, then the issue may also be with your d/f settings. Try lowering the gain and see if that helps. The head unit could be getting confused with too many strong and/or false returns.

[Gundog]

Ichthyoid,
I had this problem with my Seahawk the fix for me was to drop the transducer down and tilt it forward. I still get some interference at high speeds and ocasionally I loose bottom but it works much better than before. Before I would loose everthing when I speed up just above idle.
Mike

[No Bail]

Thanks for all the feedback. I'll drop it down and see what happens.

The transducer is level, probably the cameraman had a beer!

I'd go with lowering it too. From the picture it looks a bit higher than I mount them.

[Mikeymoto]

I agree, too high, too close to the strake. Is it a "High speed transducer?"
MM

[KChookem]

I might lower the transducer a bit, and then use something like JB Weld to fill-in and smooth the strake's welds and gap.