installing transducer question

hey, im going to install a small FF to my tin boat. this FF i already have it on the glass boat, and to install it there, i drilled 2 small holes and covered them with silicone sealer, it doesnt leaks or anything.

however, i wouldnt like to drill holes on the tin boat below the water line. so, i left the center wood board, the one for the motor, almost to the bottom of the boat, thinking about installing the transducer there.

the question is, does the transducer head needs to be below the boat?? on the bassboat it is like that, a little below the hull, but i dont know if installing it flush to the hull would impact negatively. i ask because the waters we fish are very shallow, and installing it higher would protect it a lot. i know the TM overhangs more, but sometimes we need to lift it and paddle, specially when approaching the bank, on most places the water is very shallow for several feet near the bank....

The Humminbird I just got, when following the directions correctly the bottom of the transducer will be about 1/4" below the bottom of the hull/transom. I don't know if it's like that with all brands but it is like that with this HB.

You should try and mount the transducer in a similar location and manner as the glass boat. Use 5200 to seal all the holes, and should not be any leaks.

The face of the xducer should be parallel with the bottom of the hull, outside the wash from the motor.

thanx. in order not to drill more holes below the water line i had made the motor board longer, but i guess that wont work unless the transom TM is OFF, so ill have to move the transducer to one side. today i tested it (in the center position right by the motor) and i got a weird reading, maybe its because of the transducer location (hopefully)...

shu2kill said:

thanx. in order not to drill more holes below the water line i had made the motor board longer, but i guess that wont work unless the transom TM is OFF, so ill have to move the transducer to one side. today i tested it (in the center position right by the motor) and i got a weird reading, maybe its because of the transducer location (hopefully)...

Click to expand...

That's the reason to keep it away from the motor wash (right by the motor)
What about using epoxy to adhere a small aluminum plate, into which you drill and tap mouthing holes?
It would only need to be a 1/4" piece, a few inches in dimension. Remove all paint, scuff the bare aluminum on both surfaces and use marine epoxy to attach the mount plate. Doing it that way, I wouldn't hesitate to drill two small holes for the plate. This would give added security, and the epoxy would seal it.
Use counter sunk stainless screws on the plate side and gasket the nuts on the interior.
That way, it's strong and the sealed holes wouldn't leak. It wouldn't be likely to weaken the structure either.
But if you can't bring yourself to drill, the epoxy should be adequate. Getting the plate clamped in place would be the greatest challenge.
When finished, the separate plate would allow you to remove the transducer, at will.

Drill two holes and be done with it. Use 3m 5200 or something of that nature that is meant for below the water. Don't know why people freak out over holes below the water line. Do it correctly and you'll be fine.

DrNip offers a crude but effective way of saying the same thing I've been driving at.

After rereading your OP, another idea springs to mind.

What if you mount the xducer to a piece if wood, metal, PVC, etc...lower it over the transom and arrange to clamp it in place in the desired position?

I'd still prefer a small mounting plate, but that's me.

well, i had planned on fixing the position of the transducer today after fishing in the morning. but when i went, i noticed the FF is working perfectly. i think yesterday's false readings were because i was running out of battery (i had to paddle my way back to the ramp), because today, everything worked very good. i only get a weird reading (a depth of 150 feet when im only 10 feet deep) when running the TM backwards. however, while running forward, and of curse while not running, i get a good reading. s im going to leave it like that for now...