Aluminum johnboat & transducer placement help

I sure could use some thoughts here on getting my rear mounted Humminbird 170 to work better.

I have a 15ft Alweld semi-v johnboat with ribs on the bottom ( no rivets, all welded), 25hp tiller Yamaha. Its a good little fishing rig, fuel efficient, and all I really need, as I hunt & fish year round with it. First off I know boats like this can be difficult to get good transducer readings with all the turbulance. But at this point I can only get reasonable readings when at the absolute lowest forward rpm or neutral. That's not working well at all. Any thoughts on transducer mounting changes? Hopefully the attached pics will help. I have to say I did adjust the transducer forward tilt a bit to try next time out. And you will note I have two small alum trim/planing tabs on either side of boat, those came built in. On the 2nd pic, I was trying to show how the transducer bottom is fairly parallel with the bottom of the boat and on the inside of that rightside trimtab. And I have the transducer almost centered between two ribs.

I have a HB565 mounted up on the front casting deck with its puck on the trolling motor. Works well, no real issues. But the $500-600 combo DI/SI/gps units are very interesting these days, I have no idea if those would work on my type of transom?
I do the usual bream/crappie fishing, and about to start spider rigging.

Thanks ahead of time for any thoughts or suggestions on all.



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bass tracker transducer mounting question This may help some. These are on Tracker boats though.

I would think that you should be able to get a good reading on your unit. What you are describing as your problem is pretty typical with Aluminum boats. They are so light that they don't set very deep & tend to get air under the boat especially in choppy water.

I personally would recommend a transducer mounting plate. I provided a link. I would get the 4"X12" model. I use 1. You can move the transducer to different spots without drilling a bunch of holes in your boat. Just make sure that when you mount the transducer you use screws that will NOT go all the way thru the plate into your boat.

I think part of your problem is where your transducer is mounted. Since you have a semi v bow boat the further you go out the more turbulent the water is gonna be. Personally I would move my transducer inboard between the next 2 ribs and level it back out.

Cabela's Transducer Mounting Plates, Sonar Accessories, Boating Electronics, Boating : Cabelas.com

I have my transducer thru hull on a small aluminum. Just took a small ( approx. 3 inch) piece of 4 inch PVC pipe and glued it to the floor with silicone, put TD inside flat on floor and filled it with water. Works as well or better than mounted on transom.

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Originally Posted by cache22

I have my transducer thru hull on a small aluminum. Just took a small ( approx. 3 inch) piece of 4 inch PVC pipe and glued it to the floor with silicone, put TD inside flat on floor and filled it with water. Works as well or better than mounted on transom.

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I knew you could do it on a glass boat but didn't think it worked on an aluminum boat. Guy at the boat dealer told me it wouldn't work on my Lowe.

Good to know. I'll do some check'n into it.

vexilar is the only company I know of that makes a transducer that will shoot through an aluminum hull,they are expensive but if you cant get it to work anywhere else may be an option. it's called the alumaducer ( dont know about that spelling) do a search or you may could go to vexilar's website, checked on one for my df was $150

This is a single beam transducer that came with an inexpensive HB phiranamax. Works great! shows structure, bottom, fish and works at speed on my slow little 12 footer.

Quote:

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Originally Posted by cache22

I have my transducer thru hull on a small aluminum. Just took a small ( approx. 3 inch) piece of 4 inch PVC pipe and glued it to the floor with silicone, put TD inside flat on floor and filled it with water. Works as well or better than mounted on transom.

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wow I'm going to try that, that's the way we do them on my plastic kayaks, but didn't even consider that for aluminum. I'll report back later when I trailer to the lake again. Can't be any worse that I'm getting now.

Quote:

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Originally Posted by cache22

I have my transducer thru hull on a small aluminum. Just took a small ( approx. 3 inch) piece of 4 inch PVC pipe and glued it to the floor with silicone, put TD inside flat on floor and filled it with water. Works as well or better than mounted on transom.

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Could you post up some pics for the nervous novice new guy? Is the transducer a puck style?

http://i280.photobucket.com/albums/k...allation_1.jpg

This is shown for a boat hull with a steep angle but it is the same installation for a flatter jon boat type hull. The problem with shooting a sonar signal through the hull of an aluminum boat is that here is so much signal loss on some boats. Due to the differences in the aluminum alloy used as well as differences in aluminum thickness, it would be hard to design a transducer for all aluminum boats that would work well. You can try this installation method as it is non-permanent (if you use silicone to seal the PVC to the hull).

RadaSonics designed and builds the AlumaDucer (AlumaDucer ) but you still have to be able to locate this transducer in an area that has no air bubbles flowing under it or the transducer will not work. I’ve heard mixed results from those who have tried it.

Here is mount on 12' tin boat. Works fine for me, but boat is not heavy weight aluminum. I can move the transducer to a stick mount to point sideways under docks and for structure. (Poor Boys side scan:rolleyes:Thumbs Up)Attachment 54942