Transducer location

C

C-Wolfe

Member
I will be replacing my original MFD (2006(?) Garmin GPSMAP 545S /transducer ?) with a echomap ultra 106SV and GT54UHD-TM transducer. The current unit was loosing deep quite often, I have not try very hard to figure out a pattern but I would say that it was at most planing speed and deep over 100 ft. (I was also losing deep over 600ft at any speed but that is probably related to transducer power limitation). The transducer is mounted on starboard side of centerline, I do have a scupper on port side of center line and the boat has twin engines (BF50) I don't see having much other option as to where to install the new transducer then current location but will appreciate any info anyone can provide. Hopefully the problem was due to age or wear and the upgrade will solve it but I would like to make sure there is no better location before I start drilling hole in the transom. :teeth

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A couple of comments: You want to be sure that there is as little prop wash disturbance to the transducer column. Air introduction into the water column will cause loss of bottom.

Second, you want to be able to adjust the transducer depth. The best way to do this is to put a block of High Density Polyethalyline to the transom (Starboard). You want to fix the block of HDPE to the fiberglass of the transom. There are pre-made blocks such as "Stern Saver". I make my own. I rough up the back (side to the fiberglass) with 36 grit sand paper, and make dovetail cuts into the back so that the G Flex epoxy has some tooth to stick too. I pass a flame over the back to make it better adhesion.

You can make as many holes in the HDPE block with no further intrusion into the transom. That way you can make adjustments as necessary
 
Would it be possible that I'm getting turbulence from the keel(or is it considered a strike?) and should try to move further away from it, but that will l put me closer to the outboard. As I understand it, because I don't have counter rotating engine I should be closer to the port engine since it will be on the down stroke side of the prop. unfortunately I have the scupper at that location (and a lot of turbulence). So my third best option is to keep it where it is.

I will follow Bob's advice and install a pieces of HDPE so I can move it around until I'm happy with it.
 
YES, your transducer should be on the downward rotation side of the prop. I would place it outboard to the Stbd prop. Even if you have trim tabs it can work there. (Mine has for 15 years.)

I just added a second transducer and it is about where your "scupper" is. I had one of those. Took it out, didn't like the idea of a hole in the bottom of my boat. YMMV. Bottom lock at speed, for me, has always been dependent on water surface conditions. If there is an air mixed flow under the boat, the transducer signal is sketchy. Slowing down will usually bring the pattern back. I don't fish so never really worried about that signal if I was in over 600 feet of water.

Harvey
SleepyC :moon

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forrest":2rxf6e5j said:
It looks like your transducer is a bit high. That could be the reason you are losing the bottom underway.
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Yes, that could be. When I purchased the boat the transducer was tilted quite a bit and not very reliable, I brought it back to level with little improvement. I thought I should go back a few degree but then Santa got me a whole new unit for christmas so, problem solve.
 
hardee":27i2tu6b said:
YES, your transducer should be on the downward rotation side of the prop. I would place it outboard to the Stbd prop. Even if you have trim tabs it can work there. (Mine has for 15 years.)

I just added a second transducer and it is about where your "scupper" is. I had one of those. Took it out, didn't like the idea of a hole in the bottom of my boat. YMMV. Bottom lock at speed, for me, has always been dependent on water surface conditions. If there is an air mixed flow under the boat, the transducer signal is sketchy. Slowing down will usually bring the pattern back. I don't fish so never really worried about that signal if I was in over 600 feet of water.

Harvey
SleepyC :moon

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I just assume they was not enough clearance between starboard engine and trim tab but never really check, I'll do that tomorrow, thanks. Anyone else using this location with good result?
As for getting a good reading at deeper location, for cruising it not that important but I do set shrimp pots at those deep so it nice to know accurate deep under the boat.
 
Before you drill, have you considered a Stern Saver? I have used them for the past few installs and highly recommend them to save from drilling into your transom. Just keep as far away from ANY source of cavitation that you can.

As mentioned by others, your current transducer setting appears too high. On plane, you are most likely creating an air gap which results in lost bottom tracking. I prefer to set my transducer slightly stern down and about 1/8" to 3/8" below the hull. You may have to experiment with how much you put below the hull. Once you get tracking, take a look at the fish arches. They will help you determine if you need to go more stern down or bow down to get a full arch.

Since you are on Garmin, you can record your unit INSITU with Active Captain. If you are still have problems, feel free to take some pics of your install and then post what you are seeing while you operate via the recorded footage.
 
SounderSolutions":dc6bigkr said:
Before you drill, have you considered a Stern Saver? I have used them for the past few installs and highly recommend them to save from drilling into your transom. ....
Click to expand...

I use one on my boat.
 
We've been using a cutting board (polyethylene) 12 x 18 x 1 cutting board I got on Amazon to make a number of small attachment points inside the bilge area, at $25, a bit less expensive than starboard, especially if you need a small amount. Now we're thinking of using some of it to make a "stern saver" transducer mount. Is there a reason to use gflex epoxy other than some other epoxy product for this purpose? Thanks!
 
The G Flex seems to hold better on the HDPE board. We do a series of "Dove Tail Cuts"--this allows the epoxy to get under a lip of the HDPE board, I also flame harden the surface of the HDPE board.
 
I just added a Garmin transducer to the Starboard side. I used a 6" x6" x 1" piece of Starboard and Marine 4200 sealant and let it cure for a week. I scratched up the back of the Starboard for extra grip. I will be putting my boat in the Marina in two days so I can check if it's working okay.
 
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