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-   -   New Transducer Problems/MC Hull's? (http://www.mastercraft.com/teamtalk/showthread.php?t=55286)

tockit 06-19-2013 09:50 AM

New Transducer Problems/MC Hull's?
 
This past winter, I installed a Faria Dual Temp Depth Sounder with a Thru-Hull Airmar P79 Transducer in the bilge of my 1989 Tristar.
I mounted it about a foot aft of the ski boom area, around 10 inches off centerline and I'm getting erratic and inaccurate depth readings.
I was wondering if anyone on here had dealt with this before?
The transducer installation manual mentions that my unit won't work well in boats with "cored hulls".
Is the hull in that part of the bilge on my Mastercraft "cored"?
I've tried to research it, without any luck, and I'm not sure.

CantRepeat 06-19-2013 10:09 AM

I think the only issue with these is when the transducer is mounted either too far forward or two far back.

Too far forward and you might get churned up water hitting it which could lead to poor readings. Too far back and you get cavitation off of the prop which would lead to air bubbles doing the same thing.

I've always been told that some where near the raw water pick up(IE not in front of it) and before the strut is a good place. You're looking to get the least amount of disturbed water across the point of the transducer.

tockit 06-19-2013 11:04 AM

Quote:

Originally Posted by CantRepeat (Post 948313)
I think the only issue with these is when the transducer is mounted either too far forward or two far back.

Too far forward and you might get churned up water hitting it which could lead to poor readings. Too far back and you get cavitation off of the prop which would lead to air bubbles doing the same thing.

I've always been told that some where near the raw water pick up(IE not in front of it) and before the strut is a good place. You're looking to get the least amount of disturbed water across the point of the transducer.

It doesn't even read correctly sitting still. My baseline is way off. In about 10 feet of water it was reading between 3 and 6 feet, sporadically.
If the hull isn't cored, I may have screwed up my deadrise mounting angle?

Traxx822 06-19-2013 11:07 AM

Yes the angle is the most important part. Make sure it is flat and straight. It should bounce the signal straight through your hull. But if it is not dead flat it will read wrong.

j.mccreight@hotmail.com 06-19-2013 10:37 PM

Quote:

Originally Posted by tockit (Post 948304)
This past winter, I installed a Faria Dual Temp Depth Sounder with a Thru-Hull Airmar P79 Transducer in the bilge of my 1989 Tristar.
I mounted it about a foot aft of the ski boom area, around 10 inches off centerline and I'm getting erratic and inaccurate depth readings.
I was wondering if anyone on here had dealt with this before?
The transducer installation manual mentions that my unit won't work well in boats with "cored hulls".
Is the hull in that part of the bilge on my Mastercraft "cored"?
I've tried to research it, without any luck, and I'm not sure.

Hmmm. maybe you have a bad transducer, because where you described is almost exactly where I installed mine. Mine on occasion gives a inaccurate reading at high speeds when the water is pretty murky. I used a livorsi depth sounder, which I think is like a hummingbird unit.

tockit 06-20-2013 08:35 AM

Quote:

Originally Posted by j.mccreight@hotmail.com (Post 948638)
Hmmm. maybe you have a bad transducer, because where you described is almost exactly where I installed mine. Mine on occasion gives a inaccurate reading at high speeds when the water is pretty murky. I used a livorsi depth sounder, which I think is like a hummingbird unit.

I almost positive I screwed up my deadrise angle when I installed the transducer mount after looking back over the installation instructions.

Did you locate your transducer with the boat in the water or on the trailer?

The instructions recommend putting the boat in the water and I'm sure that's a good idea, but I'm gonna be using my depth sounder primarily for locating shallow water, so I'll probably just locate it with the boat on the trailer.
I'm not overly concerned if it's off a few feet in 100' of water.

What did you guy's use to glue the transducer base to the hull?

tockit 06-24-2013 02:50 PM

I tried troubleshooting my transducer again at the lake this past Saturday.
I found a spot of water 10 foot deep and anchored, while trying to get a consistent reading.
If I take the transducer and put it directly against the hull, I get a good reading; but if I put it in the mount it's about 6' off. After re-reading the instructions, I realized that I hadn't put the antifreeze/mineral oil inside my mount base.
What is the purpose of the antifreeze and would not having it in there cause my problems?
Thanks!

catamount 06-24-2013 05:10 PM

Antifreeze in the base? I'm not sure what your instructions involve, but I know that with the humminbird you can't really get good "dry" results because even the slightest bit of air between the face of the transducer and the hull will throw it off.

To test position, they recommend putting the transducer on a ziploc full of water, sitting on the hull = no air beneath.

See this, that I just copied & pasted:

How to Install Shoot-Thru (Epoxy In Hull) Transducer:

First: It is recommended to test the location prior to installation. Hull construction can have effects on getting good readings and it's best to find the best location. Air Pockets, Areas that Glass Matts Overlap, Delamination of Hull can effect the sonar performance. The best wasy is to disable automatic bilge pump temporarily and add a couple inches of water to the hull. Next build a small sand bag using a Ziploc bag. Place transducer in hull and using sand bag hold it down to find the best location for installation. Normally the closer to the rear of the boat and center of the boat the higher speed the sonar will stay locked on. Make sure the location is away from strakes underneath as these will cause aerated or turbulated water underneath and disrupt the clean water flow accross the bottom of the hull which can effect sonar readings.

Second: Mark the location of the best readings and drain the water and allow hull to dry. Hull must be dry for epoxy to adhere and set-up.

Third: I like to sand or smooth out area of hull the transducer is mounted so it's flat and smooth surface.

Fourth: Using Plumber's Putty or Play Do build a small dam around the Area the transducer will installed about an 1" wider than transducer to keep epoxy from flowing during installation.

Fifth: Use Slow Cure Epoxy - I recommend the epoxy that comes with the transducer direct from Humminbird. Slow Cure Epoxy stays cooler than fast cure. DO NOT use silicone or any other material than epoxy. Silicone can absorb sonar waves and creates alot of issues. Mix thoroughly until consist color. Avoid whipping while mixing to reduce creating air bubbles in the epoxy. The less air bubbles the better the final results and improved sonar readings.

Sixth: I like to apply a thin layer of epoxy on the transducer, I also like to apply a thin layer pressed into the bottom of the dam to squeeze out any potential air bubbles between epoxy and hull. Fill the rest of the dam with remaining epoxy.

Seventh: Installation of transducer. As you push transducer into the epoxy start 90‚° from foward and push and slowly turn the quarter turn. This will helps squeeze out air bubbles under the transducer.

Eighth: Using Sandbag from step one place on top of transducer to hold it in place. And allow the epoxy to cure for a minimum of 24 hours.

Ninth: Remove Sandbag and Plumbers Putty. Your Transducer is now installed and ready to use.

Tenth: Test Transducer in the Water to make sure you have good sonar readings. If not you may have air the epoxy and may need to repeat procedure to get good sonar readings.

tockit 06-24-2013 09:55 PM

Quote:

Originally Posted by catamount (Post 950382)
Antifreeze in the base? I'm not sure what your instructions involve, but I know that with the humminbird you can't really get good "dry" results because even the slightest bit of air between the face of the transducer and the hull will throw it off.

Catamount,
Thanks for the info!
The Airmar Transducer installation instructions tell you to fill the transducer base with 2.4 oz of Propylene Glycol which, from what I've read is RV Antifreeze.
I've read on other websites of people using mineral oil, baby oil, water, etc.
Water freezes and can crack the base or evaporate, and apparently mineral oil can eat away the bonding agent over time, is why they recommend antifreeze.
I was just curious why you needed a fluid medium under the transducer and you've answered my question.
Thanks again!


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