Transducer kicking up spray

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CRB357

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I’m a transducer gps/fishfinder rookie. Never had a boat with one before. The previous owner had the transducer mounted right in front of a “strake”, I guess that is what that is called. It kicked up a lot of spray all over the motor etc. It no longer worked so we got a new Garmin unit. Followed instructions and mounted new transducer in what I believe is a good spot. It’s supposed to sit slightly below the boat, like 3/8”. First time out and it’s kicking up spray just like the other one. I want to raise it up to level with boat or slightly above. However I already have 5-6 holes back there and don’t want to put any more than necessary. So I want the next location to be right. Any advice? IMG_4329.jpegIMG_4328.jpeg
 
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By the way the readings work great where it currently mounted. Depth works at 35mph plus. So I think I can raise it some before readings at speed suffer. Only problem is I don’t have anymore upward adjustment left bc I’m at the limit of the bracket. Have to move bracket up more requiring more screw holes. So I really want to get this correct this time. I’m thinking just about 1/2-3/4” higher and that would still give me some adjustment to go lower if needed.
 
Each transducer design is different, so lots of experimenting is needed. I see you have a large weld bead at the transom edge to that will cause a disturbance. Just based on your pics, you might need to be deeper but closer to the transom then angled slightly with the rear slightly lower than the front. Each design offers a different challenge, especially on aluminum boats where ribs, rivets, and welds all cause interference. As mentioned get a mounting plate so no more holes thru your transom. In sever situations, I have had to use bondo ( auto body filler) to create a smooth surface on the bottom of the hull to allow the transducer to read. Honestly, if the spray is not comming into your boat and causing a problem....so what!
 
Please report back. I have a similar problem, but haven't tried to fix it. My transducer will only work at high speeds if the water is calm. I assume it's due to the flat bottom and turbulence of the water. It's worked that way with multiple transducers, so I don't think it's a problem with a brand. I would like to fix the spray.
 
I’m a transducer gps/fishfinder rookie. Never had a boat with one before. The previous owner had the transducer mounted right in front of a “strake”, I guess that is what that is called. It kicked up a lot of spray all over the motor etc. It no longer worked so we got a new Garmin unit. Followed instructions and mounted new transducer in what I believe is a good spot. It’s supposed to sit slightly below the boat, like 3/8”. First time out and it’s kicking up spray just like the other one. I want to raise it up to level with boat or slightly above. However I already have 5-6 holes back there and don’t want to put any more than necessary. So I want the next location to be right. Any advice? View attachment 117923View attachment 117924
Looks like you can flip the bracket over and gain some room👍🏼 good luck
 
It‘s probably a good idea to add a HDPE plastic plate to the transom. (Cutting board) This will allow you to move the transducer around without turning the transom into Swiss cheese.

Try searching, “HDPE TRANSDUCER MOUNT” and you will find plenty of info and products.
Or.. swing away transducer mounted on a vinyl railing post for beaching/breakaway...lots of adjustment options..
 

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Mounted many transducers in my 60 yrs of boating, found that most all of them work best when slightly angled back.
In other words the rear of the transducer needs to be slightly lower than the front. If the opposite way they tend to collect air bubbles on the face and give false readings.
Front edge of transducer needs to be as close as possible to the transom to get smoothest water flow from the hull.
When you get poor readings it is normally due to air bubbles on the face.
 
My first thought is the same as LDUBS. My Humminbird also came with a plug to fill the gap between the mount and the transducer.

I had the same issue with a different portable transducer mount this past season. The gap between mount and transducer directed water flow up and even over the transom at speeds above about 10 MPH. Once I interrupted that flow, the spray stopped.

Very interested to hear how your improvised solution works. If it's solved with that tape, you'll probably want to affix something more lasting into that gap. If it was me, I'd find a way to shape a small block of PVC into that gap.
 
Just got back from hunting. While the spray isn’t tall anymore, it’s still kicking up on the motor. I think raising it 1/2 to 3/4 will help a lot. Should try again for Thanksgiving weekend.
 
In the second original pic that transducer looks low to me too. Bottom of my transducer is 1/8" below the hull bottom line. But, mine is a Humminbird and that is what they say. If Garmin says 3/8" then they must have a reason.
 
In the second original pic that transducer looks low to me too. Bottom of my transducer is 1/8" below the hull bottom line. But, mine is a Humminbird and that is what they say. If Garmin says 3/8" then they must have a reason.
Garmin said 1/8 for fiberglass and 3/8 for aluminum hulls.
 
Garmin said 1/8 for fiberglass and 3/8 for aluminum hulls.
Typically true, gotta get in clean water from the welds, rivets and the other slight deformities found on aluminum hulls. Sometimes a filler is needed to smooth that transition from hull bottom to the transducer so bubbles don't form. Glass boats have far fewer deformities so the trasnducer can run closer to the hull bottom
 
Garmin said 1/8 for fiberglass and 3/8 for aluminum hulls.
Typically true, gotta get in clean water from the welds, rivets and the other slight deformities found on aluminum hulls. Sometimes a filler is needed to smooth that transition from hull bottom to the transducer so bubbles don't form. Glass boats have far fewer deformities so the trasnducer can run closer to the hull bottom

That sure makes sense to me.
 
Typically true, gotta get in clean water from the welds, rivets and the other slight deformities found on aluminum hulls. Sometimes a filler is needed to smooth that transition from hull bottom to the transducer so bubbles don't form. Glass boats have far fewer deformities so the trasnducer can run closer to the hull bottom
X2. I know mine would work better if it wasn’t for my hull. Never thought of using something to smooth it out for the transducer.
 
X2. I know mine would work better if it wasn’t for my hull. Never thought of using something to smooth it out for the transducer.
My Islander gad issues getting a good read, when you looked close, there were some rivets in line and no place to move the transducer out of the way. Mixed up some bondo and created a smooth path about 10" forward and built a little " bridge" to close the gap between transom and transducer. A minor tweak to the angle and it read great !!
Bubbles cause problems, need clean ,clear water over the face. Because each transducer mfgr has a different shape/ design, tou gotta experiment.
 

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