I am hoping some of my OSO brothers can help me on this one..

I have a 1987 Formula F223LS with a Stock 454 and Alpha..(don't laugh..)

My boat orginally had some old time depthsounder unit that was DOA. So, late last season, I purchased a Garmin 160 Blue fishfinder/depth/speedo/temp unit. It has a transom mounted transducer, which is larger than any previous one I have ever seen or used before. The thing hangs at least 4" off the transom and has a rather large surface area exposed to the water. I mounted it in the SAME location as the previous unit and did so according to the instructions. The transducer is a AIRMAR P66 unit (www.airmar.com).

Everything seems fine at slow speeds (<15 mph), but sometimes when I am getting the boat up on plane, or "briefly" leave the water surface over a wave, the transducer 'kicks up' off its bracket. This feature is for the protection of the transducer, but it is also aggravating me to no end. The other problem is that when it is securely fastened at high speed (>30 mph), I sometimes lose all depth soundings on the display (i.e. display reads "1049 ft" or "---". The head unit will eventually reset itself at speed or after I have slowed down.

I called AIRMAR and they told me to adjust the height of the transducer (deeper into the water than the 1/8" they specified) with the bracket (due to it possibly aerating), the problem was still there. They then sent me a new plastic bracket to eliminate the popping, and it still does not help. The unit still keeps popping up and it does not read consistantly. I told AIRMAR that I am not going to drill more holes all over my transom to test different locations as they wanted me to try. I am fairly confident that the transducer is seeing uninterrupted, non-aerated waterflow.

My comments/questions are as follows:

1. There seems to be a LOT of surface area on the bottom of this transducer, which at higher speeds/loads, seems to override the pivot snap latch built into the unit. Is this common with all Garmin units?

2. I am wondering if this unit is really for performance applications. Can I get a different transducer more suited to this application? (without drilling more holes in my transom)

3. If not the correct type, what unit should I look for that will be comparable to the features of the Garmin, and with a more suitable transducer? (i.e. Raymarine, Navman, Standard, etc.)

Thanks for any help/advice you can give!

Regards,

-Larry

I would say that it is not for performance applications. My HDR600 that Gaffrig sells made by huminbird cuts out at speeds above 55. That model is suppose to be the high performance model. As for the surface area I think that the plastic bracketrs are going to continue to "pop" because of all the pressure that transducer is seeing at higher speeds.

ljsmith1

I did the same thing. But I bought the Garmin 240 Blue. Probably the same transducer as the 160 Blue. Friggen thing is huge...well it was huge. Mine popped off after jumping a freighter wake on the St. Lawrence river near Alexandria Bay last year. Made the re-entry, heard a loud "thump". Turned around to look behind us, and saw a big black thing flying through the air. Had no idea what it was so I stopped the boat and jumped in the water and found the transducer wire dangling. Stopped in at Boat US and picked up another one. Still haven't put it on as there's no doubt it will just pop off again. I was thinking of fabricating a rigid bracket out of flat stock aluminum and securing the transducer to that, then mount the rigid bracket to the transom. But I'm afraid of damaging the transom. If anyone comes up with a workable solution I'd sure like to hear it.

I wonder what guys with bass boats use. He!!, some of those boats are pretty fast. Do they use transom mounted transducers??