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post #33 of Old 07-24-2012
Learning the HARD way...
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Re: Fishfinder vs depth sensor

Originally Posted by wolfenzee View Post
I would rather have a depth gauge with a relatively small display and great big numbers...instead I have a fish finder that is so big it has to be mounted just inside the companionway hatch, the actual depth numbers are really small and I hit my head on it while cooking have moved it twice and is in he least bad place.
For those who might want to suggest I just buy a depth gauge...the whole set up isn't cheap, then add hauling the boat and time on the hard....I would end up spending $500+ to buy and install a "cheap" $100 depth sounder. I can't find just a depth sounder the uses my old Si Tex transducer
My current through-hull transducer will remain in place - at least until this fall.

I bought the Garmin echo because I can mount it at the binnacle, where the Signet Marine depth sounder is currently mounted, and because I believe it is powerful enough to allow me to convert the tranducer to shoot through the hull (I will soon see).

Per Garmin, here is how;
Can a transom mount transducer be mounted like an in-hull transducer?

Due to having a boat that is incompatible with a transom mount transducer, it may be desirable to install a transom mount transducer inside of the hull, sometimes called a shoot-thru-the-hull installation. If the boat is made of solid fiberglass, it is possible to install a transom mount transducer inside of the hull. When using a 500W transducer, the fiberglass hull can be no thicker than 5/8 inch. When using a 1kW (1000W) transducer, the fiberglass hull can be no thicker than 1 inch.

The following factors should be considered when installing the transducer in the hull:

The hull must be composed of solid fiberglass without air bubbles, laminates, fillers, or dead air space
The location must be in an area of clean (non-turbulent) water at all speeds
The location must not be over any strakes or behind any obstruction on the hull that would create turbulence

Many modern hulls have a dedicated pocket for an in-hull transducer installation. Please check with the hull manufacturer to see if your boat includes this pocket.

To test a location for in-hull installation:

Fabricate a test cylinder from a section of PVC pipe or can large enough to contain the transducer
If no PVC pipe or can is available, a plastic bag filled with water can also be used
Temporarily seal the test cylinder to the hull with caulking or RTV sealer, and fill the test device with water or light mineral oil
Place the transducer in the liquid, pointed directly toward the bottom, and weighted down to ensure the most accurate test results
Using the attached Garmin fish finder/sounder, verify that the transducer is reading depths. Be sure to test at different depths and speeds, to ensure that the transducer is working properly
If the sonar performance is significantly degraded, select and test another location

To permanently install the transducer:

Lightly sand the surface of the hull and the face of the transducer with 400-grit wet or dry sandpaper
Build a dam using strip caulk about 1/4 inch tall
Pour about 1/8 inch of two-part, slow-cure epoxy into the dam
Place the transducer into the epoxy, turning the transducer to work out any air bubbles
Weight the transducer in place, and allow it to cure for 24 hours

Last edited by eherlihy; 07-24-2012 at 07:11 AM.
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