Shoot thru aluminum hull?

[fat_fish55]

hey was wondering if it works to lay transducer on the hull of an aluminum boat or if you need special stuff or if it is even possible at all
any idea would be appreciated
thanks

[rcneman]

ya know, i just purchased a Lowrance x125 and in the installation section it showed that you could mount it to the bottom of the hull. I would like to try it out and see what happens, but the only problem is that it says for the best signal and mounting you need to epoxy it to the bottom and "it will be almost impossible to remove if properly epoxied"...argh!

i would like to try the hull mount, but crap if it doesn't work too well, i'm kinda screwed outta $330!! doh!

cyas
rc

[Greg Walters]

Fat fish55,

Most sonar manufacturers will tell you that this will not work and this is what we (Humminbird) would normally tell you as well. The fact is; it can work but won’t in most cases. The speed of sound through aluminum is very different from the speed of sound through fiberglass. You get more signal loss when ‘shooting’ a sonar signal through aluminum versus fiberglass. Now it could be done if a unit and/or transducer were designed to do so but what you could run into is the differences in aluminum thickness and alloys. There is a company (RadarSonics) that has developed a transducer that they claim will work through aluminum boat hulls (I have not tested one myself but have no reason to not believe them). You may or may not want to look into using one of these.

What you can do for now is to test the transducer that you have to see if it will work well enough for your needs. The easiest way to do this would be to place the transducer face down in the boat’s hull in the area you want to mount it in. Pour enough water into the hull to cover the transducer and than cover it with something to keep it from tipping over and moving around while you test it on the water. The water will displace the air and couple the sonar signal to the boat hull (and the boat hull couples it to the water…).

An option for this would be to build a dam out of some material that will hold water in the area that the transducer is in.

Another option and one that could easily be made permanent if it worked is to silicone a piece of PVC pipe to the boat’s hull. This needs to be vertical so that one end is sealed to the boat hull and the other end is up. It needs to be long enough and of a big enough diameter that the transducer can fit inside and be covered with water. The silicone should only be used around the edge of the PVC to seal it to the hull so that it holds water and not under the area that the transducer will be sitting in. Once the PVC is sealed in place and the silicone has dried, place the transducer inside and fill the PVC tube with water.

In all cases; make sure that the inside of your boat’s hull is clean before starting.

Now test your installation: while out on the water, find an area as deep as you can (that your depth sounder will read to) that is also relatively flat. Turn your sonar unit on and note the signal strength of the bottom reading signal and also any weak sonar targets such as a thermocline or baitfish. Next, hang the transducer over the side of the boat so that it is pointing straight down. Again note the signal strength of the bottom reading signal and also any weak sonar targets and compare them to the readings you got when the transducer was mounted inside your boat’s hull. This will show you what you are losing signal strength wise and will also show whether your sonar/transducer combination will work well enough inside the boat’s aluminum hull or not.

Your testing isn’t completed yet until you check the readings at high-speed (if this is a concern to you). Run your boat at high-speed and note whether your unit is able to show a reading or not. If it doesn’t you may have to trying another mounting area in your boat’s hull. Please note that it is not always possible to find such a location on all boats and shooting a signal through the hull will make it even harder to do so.

Good luck!


Greg Walters at Humminbird
gwalters@johnsonoutdoors.com

[flaboy]

sorry guys but you can't shoot thru a metal hull. fiberglass yes!

[ShilohRed]

http://www.cabelas.com/information/B...83017844a.html

That is the only one I know that will work. The others if you will read your manual is for glass boats only.
Pete