Wide Beam Transducer vs. Keel

[Damon]

Has anyone installed a wide beam/side scan transducer? My concern is the keel causing interference while transmitting. Seriously considering installing the following Furuno transducer with their DFF-3D Mulit-beam fishfinder:




This transducer is a 120-degree beam unit. If I install this forward of the motor, do you think the transmission will clear the keel? I figure the fairing block will bring the face of the transducer a few inches below the hull.

[tuner]

Hi Damon,

I inquired with Simrad about using a similar Airmar transducer and they said the keel would be a problem and they suggested a split system with two transducers set on opposite sides of the keel.

https://www.simrad-yachting.com/simrad/type/sonar-and-transducers/structurescan-3d-ss-thruhull-dual/

Build a mock-up so you can check the beam angle from the transducer.

[Ship]

here is the auto cad spread at 120 degrees

[Damon]

here is the auto cad spread at 120 degrees

I think 1” - 8 13/16” would be to far the centerline to install the transducer. With the auto CAD spread, can you do two of them with the transducer 6” and 12” off centerline?

[Damon]

Hi Damon,

I inquired with Simrad about using a similar Airmar transducer and they said the keel would be a problem and they suggested a split system with two transducers set on opposite sides of the keel.

https://www.simrad-yachting.com/simrad/type/sonar-and-transducers/structurescan-3d-ss-thruhull-dual/

Build a mock-up so you can check the beam angle from the transducer.

Unfortunately, I don’t have a trailer to pull the boat out of the water. Did you install those side scan transducers?

[tuner]

Due to the cost, I did not install them.

Give me a distance from the transom and the keel and I will check the 120* clearance to the keel.

[Ship]

Yes I can. I will draw it up and post latter today. I have to be at my desk top. Do you want them at 120* or 60 *? If I don't hear back from you quickly, I'll draw both and post the 120*.

[Ship]

Also remember that you can mount your transducer parallel to the hull giving it about a 12* tilt away from the keel.

[Ship]

I drew an approximate keel so you'd see the cut off of the beam. I took a picture so you'd see the color difference between the 6" spread and the 12" spread. The keel is magenta.

[Ship]

Here's the 60* spread.

[Damon]

Thanks guys! I think the transducer transmission is going to clear the keel. Jim “IBfishing” measured 48” forward of the raw water inlet (this would put the transducer about 6” aft of the bulkhead in front of the engine), and the keel measured 4-3/4” there. Plus, the transducer surface will be about 2” off the hull surface with the high speed fairing block.